215 results on '"Marco Cremona"'
Search Results
2. Pulsed‐Laser‐Driven CO2 Reduction Reaction for the Control of the Photoluminescence Quantum Yield of Organometallic Gold Nanocomposites
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Tahir, Guilherme C. Concas, Mariana Gisbert, Marco Cremona, Fernando Lazaro, Marcelo Eduardo H. Maia da Costa, Suellen D. T. De Barros, Ricardo Q. Aucélio, Tatiana Saint Pierre, José Marcus Godoy, Diogo Mendes, Gino Mariotto, Nicola Daldosso, Francesco Enrichi, Alexandre Cuin, Aldebarã F. Ferreira, Walter M. de Azevedo, Geronimo Perez, Celso SantAnna, Braulio Soares Archanjo, Yordy E. Licea Fonseca, Andre L. Rossi, Francis L. Deepak, Rajwali Khan, Quaid Zaman, Sven Reichenberger, Theo Fromme, Giancarlo Margheri, José R. Sabino, Gabriella Fibbi, Mario Del Rosso, Anastasia Chillà, Francesca Margheri, Anna Laurenzana, and Tommaso Del Rosso
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CO2 reduction reaction ,laser synthesis and processing of colloids in water ,organometallic colloidal nanocomposites ,photoluminescence quantum yield ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Over the last decade, the CO2 reduction reaction (CO2RR) has been increasingly exploited for the synthesis of high‐value raw materials in gaseous or liquid form, although no examples of CO2 fixation in nanoparticle systems have been demonstrated. Herein, CO2 fixation into solid nanomaterials by laser synthesis and processing of gold colloids in water, traditionally considered a green approach leading to ligand‐free nanoparticles without the formation of by‐products, is reported. If carbon monoxide‐rich gold nanoparticles are observable even after synthesis in deionized water, the presence of CO2 derivatives in alkaline water environment leads to C2 and C3 coupling with the production of carboxylic acids as a typical CO2RR fingerprint. While laser processing of preformed gold colloids is selective for C2 coupling, both C2 and C3 coupling to lactic acid are observed during pulsed laser ablation of a gold target. In the latter case, it is demonstrated that it is possible to synthesize photoluminescent organometallic nanocomposites in the blue spectral region with a quantum yield of about 20% under adequate experimental conditions. In this research, new pathways are offered to be explored in energetics, photonics, catalysis, and synthesis at the nanoscale.
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- 2024
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3. Highly Luminescent Europium(III) Complexes in Solution and PMMA-Doped Films for Bright Red Electroluminescent Devices
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Zubair Ahmed, Rafael dos Santos Carvalho, Aline Magalhães dos Santos, Francesca Gambassi, Elisa Bandini, Lorenza Marvelli, Lucia Maini, Andrea Barbieri, and Marco Cremona
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europium complexes ,crystal structure ,photoluminescence ,electroluminescence ,OLED ,Organic chemistry ,QD241-441 - Abstract
This paper reports the synthesis, structure, photophysical, and optoelectronic properties of five eight-coordinate Europium(III) ternary complexes, namely, [Eu(hth)3(L)2], bearing 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione (hth) as a sensitizer and L = H2O (1), dpso (diphenyl sulphoxide, 2), dpsoCH3 (4,4′-dimethyl diphenyl sulfoxide, 3), dpsoCl (bis(4-chlorophenyl)sulphoxide, 4), and tppo (triphenylphosphine oxide, 5) as co-ligands. The NMR and the crystal structure analysis confirmed the eight-coordinate structures of the complexes in solution and in a solid state. Upon UV-excitation on the absorption band of the β-diketonate ligand hth, all complexes showed the characteristic bright red luminescence of the Europium ion. The tppo derivative (5) displayed the highest quantum yield (up to 66%). As a result, an organic light-emitting device, OLED, was fabricated with a multi-layered structure—ITO/MoO3/mCP/SF3PO:[complex 5] (10%)/TPBi:[complex 5] (10%)/TmPyPB/LiF/Al—using complex 5 as the emitting component.
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- 2023
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4. Quenching of the Photoluminescence of Gold Nanoclusters Synthesized by Pulsed Laser Ablation in Water upon Interaction with Toxic Metal Species in Aqueous Solution
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Tahir, Fernando Lazaro Freire Jr, Ricardo Q. Aucelio, Marco Cremona, Juliana da S. Padilha, Giancarlo Margheri, Quaid Zaman, Guilherme C. Concas, Mariana Gisbert, Sajjad Ali, Carlos A. T. Toloza, Yordy E. Licea, Tatiana D. Saint’Pierre, Rafael S. Carvalho, Rajwali Khan, Gino Mariotto, Nicola Daldosso, Geronimo Perez, and Tommaso Del Rosso
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pulsed laser ablation in water ,gold nanocluster ,photoluminescence ,mercury II ions ,Biochemistry ,QD415-436 - Abstract
Sensors for the detection of heavy metal ions in water are in high demand due to the danger they pose to both the environment and human health. Among their possible detection approaches, modulation of the photoluminescence of gold nanoclusters (AuNCs) is gaining wide interest as an alternative to classical analytical methods based on complex and high-cost instrumentation. In the present work, luminescent oxidized AuNCs emitting in both ultraviolet (UV) and visible (blue) regions were synthesized by pulsed laser ablation of a gold target in NaOH aqueous solution, followed by different bleaching processes. High-resolution electron microscopy and energy-dispersive X-ray scattering confirmed the presence of oxygen and gold in the transparent photoluminescent clusters, with an average diameter of about 3 nm. The potentialities of the bleached AuNCs colloidal dispersions for the detection of heavy metal ions were studied by evaluating the variation in photoluminescence in the presence of Cd2+, Pb2+, Hg2+ and CH3Hg+ ions. Different responses were observed in the UV and visible (blue) spectral regions. The intensity of blue emission decreased (no more than 10%) and saturated at concentrations higher than 20 ppb for all the heavy metal ions tested. In contrast, the UV band emission was remarkably affected in the presence of Hg2+ ions, thus leading to signal variations for concentrations well beyond 20 ppb (the concentration at which saturation occurs for other ions). The limit of detection for Hg2+ is about 3 ppb (15 nmol/L), and the photoluminescence intensity diminishes linearly by about 75% up to 600 ppb. The results are interpreted based on the ligand-free interaction, i.e., the metallophilic bonding formation of Hg2+ and Au+ oxide present on the surface of the UV-emitting nanoclusters.
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- 2023
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5. Review of Bacterial Nanocellulose as Suitable Substrate for Conformable and Flexible Organic Light-Emitting Diodes
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Thales Alves Faraco, Marina de Lima Fontes, Rafaella Takehara Paschoalin, Amanda Maria Claro, Isabella Salgado Gonçalves, Mauricio Cavicchioli, Renan Lira de Farias, Marco Cremona, Sidney José Lima Ribeiro, Hernane da Silva Barud, and Cristiano Legnani
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OLED ,FOLED ,BNC ,bacterial nanocellulose ,Organic chemistry ,QD241-441 - Abstract
As the development of nanotechnology progresses, organic electronics have gained momentum in recent years, and the production and rapid development of electronic devices based on organic semiconductors, such as organic light-emitting diodes (OLEDs), organic photovoltaic cells (OPVs), and organic field effect transistors (OFETs), among others, have excelled. Their uses extend to the fabrication of intelligent screens for televisions and portable devices, due to their flexibility and versatility. Lately, great efforts have been reported in the literature to use them in the biomedical field, such as in photodynamic therapy. In tandem, there has been considerable interest in the design of advanced materials originating from natural sources. Bacterial nanocellulose (BNC) is a natural polymer synthesized by many microorganisms, notably by non-pathogenic strains of Komagataeibacter (K. xylinus, K. hansenii, and K. rhaeticus). BNC shows distinct physical and mechanical properties, including its insolubility, rapid biodegradability, tensile strength, elasticity, durability, and nontoxic and nonallergenic features, which make BNC ideal for many areas, including active and intelligent food packaging, sensors, water remediation, drug delivery, wound healing, and as conformable/flexible substrates for application in organic electronics. Here, we review BNC production methods, properties, and applications, focusing on electronic devices, especially OLEDs and flexible OLEDs (FOLEDs). Furthermore, we discuss the future progress of BNC-based flexible substrate nanocomposites.
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- 2023
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6. Recent advances with optical upconverters made from all-organic and hybrid materials
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Roland Hany, Marco Cremona, and Karen Strassel
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upconverter ,photodetector ,near-infrared ,organic light-emitting device ,nir imaging ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Biotechnology ,TP248.13-248.65 - Abstract
The growing interest in near-infrared (NIR) imaging is explained by the increasing number of applications in this spectral range, which includes process monitoring and medical imaging. NIR-to-visible optical upconverters made by integrating a NIR photosensitive unit with a visible emitting unit convert incident NIR light to visible light, allowing imaging of a NIR scene directly with the naked eye. Optical upconverters made entirely from organic and hybrid materials – which include colloidal quantum dots, and metal-halide perovskites – enable low-cost and pixel-free NIR imaging. These devices have emerged as a promising addition to current NIR imagers based on inorganic semiconductor photodiode arrays interconnected with read-out integrated circuitry. Here, we review the recent progress in the field of optical upconverters made from organic and hybrid materials, explain their functionality and characterization, and identify open challenges and opportunities.
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- 2019
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7. Synthesis of Organic Semiconductor Nanoparticles with Different Conformations Using the Nanoprecipitation Method
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Nathalia A. Yoshioka, Thales A. Faraco, Hernane S. Barud, Sidney J. L. Ribeiro, Marco Cremona, Benjamin Fragneaud, Indhira O. Maciel, Welber G. Quirino, and Cristiano Legnani
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organic semiconductor nanoparticles ,P3HT ,PC71BM ,nanoprecipitation method ,aqueous suspensions ,Organic chemistry ,QD241-441 - Abstract
In recent years, nanoparticulate materials have aroused interest in the field of organic electronics due to their high versatility which increases the efficiency of devices. In this work, four different stable conformations based on the organic semiconductors P3HT and PC71BM were synthesized using the nanoprecipitation method, including blend and core-shell nanoparticles. All nanoparticles were obtained free of surfactants and in aqueous suspensions following the line of ecologically correct routes. The structural and optoelectronic properties of the nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-visible absorption spectroscopy and UV-visible photoluminescence (PL). Even in aqueous media, the blend and core-shell nanoparticles exhibited a greater light absorption capacity, and these conformations proved to be effective in the process of dissociation of excitons that occurs at the P3HT donor/PC71BM acceptor interface. With all these characteristics and allied to the fact that the nanoparticles are surfactant-free aqueous suspensions, this work paves the way for the use of these colloids as a photoactive layer of organic photovoltaic devices that interface with biological systems.
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- 2022
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8. Novel Scintillating Nanoparticles for Potential Application in Photodynamic Cancer Therapy
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Bianca A. da Silva, Michael Nazarkovsky, Helmut Isaac Padilla-Chavarría, Edith Alejandra C. Mendivelso, Heber L. de Mello, Cauê de S. C. Nogueira, Rafael dos S. Carvalho, Marco Cremona, Volodymyr Zaitsev, Yutao Xing, Rodrigo da C. Bisaggio, Luiz A. Alves, and Jiang Kai
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nanoparticles ,rare earth oxides ,photodynamic therapy ,cancer ,nanosilica ,Pharmacy and materia medica ,RS1-441 - Abstract
The development of X-ray-absorbing scintillating nanoparticles is of high interest for solving the short penetration depth problem of visible and infrared light in photodynamic therapy (PDT). Thus, these nanoparticles are considered a promising treatment for several types of cancer. Herein, gadolinium oxide nanoparticles doped with europium ions (Gd2O3:Eu3+) were obtained by using polyvinyl alcohol as a capping agent. Hybrid silica nanoparticles decorated with europium-doped gadolinium oxide (SiO2-Gd2O3:Eu3+) were also prepared through the impregnation method. The synthesized nanoparticles were structurally characterized and tested to analyze their biocompatibility. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy confirmed the high crystallinity and purity of the Gd2O3:Eu3+ particles and the homogeneous distribution of nanostructured rare earth oxides throughout the fumed silica matrix for SiO2-Gd2O3:Eu3+. Both nanoparticles displayed stable negative ζ-potentials. The photoluminescence properties of the materials were obtained using a Xe lamp as an excitation source, and they exhibited characteristic Eu3+ bands, including at 610 nm, which is the most intense transition band of this ion. Cytotoxicity studies on mouse glioblastoma GL261 cells indicated that these materials appear to be nontoxic from 10 to 500 μg·mL−1 and show a small reduction in viability in non-tumor cell lines. All these findings demonstrate their possible use as alternative materials in PDT.
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- 2022
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9. Self-Supported Smart Bacterial Nanocellulose–Phosphotungstic Acid Nanocomposites for Photochromic Applications
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Moliria V. Santos, Hernane S. Barud, Monica A. S. Alencar, Marcelo Nalin, Sérgio H. Toma, Koiti Araki, Assis V. Benedetti, Indhira O. Maciel, Benjamin Fragneaud, Cristiano Legnani, Celso Molina, Marco Cremona, and Sidney J. L. Ribeiro
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bacterial nanocellulose ,photochromism ,polyoxometalates ,phosphotungstic acid ,electrochromism ,Technology - Abstract
Bacterial nanocellulose (BNC) is a natural biopolymer obtained by gram-negative bacteria by means of a green and inexhaustible biotechnological process using glucose as producing source. BCN hydrogels is formed by cellulose nanofibrils that maintain an open network structure, an ideal matrix to produce new class of organic-inorganic nanocomposites (OIN) for multifunctional applications. The polyoxometalates (POMs) are complex molecules with several metallic ions sharing oxide ions, forming a highly symmetrical metal oxide cluster. Phosphotungstic acid (PWA), H3PW12O40 photoreduction process activated under ultraviolet irradiation, promoting color change. In this work, photochromic organic-inorganic nanocomposites were prepared by soaking phosphotungstic acid (H3PW12O40) in wet BNC membranes mats at room temperature. Semi-transparent and free-standing BNC/PWA nanocomposite with paper-like aspect were obtained. BNC network was able to control, stabilize and disperse PWA particles in a narrow nanometric distribution, and FTIR spectra indicated that the primary Keggin structure was also preserved in the nanocomposites, independently on the PWA content. The nanoparticles present a narrow distribution of around 16 nm, independently on the PWA concentration. BNC/PWA nanocomposites showed reversible photochromic behavior characteristic of the equilibrium between different tungsten oxidation states. PWA reduction (W6+→ W5+) and organic matrix oxidation is proposed to occur through a radical process involving the interaction of one electron from the oxygen atom of the PWA and one hydrogen from BNC matrix. The photochromic effect vanishes almost completely after 5 h. This mechanism is real in the presence of oxygen, however, if the membranes are left in nitrogen or under vacuum the blue color remains longer than 45 days. Photo-electrochemical behavior was studied by spectroelectrochemistry measurements. It is worth noting that all processes were still reversible in the timescale of the experiment and color changes were observed in several cycles.
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- 2021
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10. The Influence of Calcination Temperature on Photocatalytic Activity of TiO2-Acetylacetone Charge Transfer Complex towards Degradation of NOx under Visible Light
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Lucas A. Almeida, Margarita Habran, Rafael dos Santos Carvalho, Marcelo E. H. Maia da Costa, Marco Cremona, Bruno C. Silva, Klaus Krambrock, Omar Ginoble Pandoli, Edisson Morgado Jr., and Bojan A. Marinkovic
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ligand to metal charge transfer ,nanocrystalline ,anatase ,oxygen-based bidentate ,sol-gel ,superoxide anion radical ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
The improvement of photocatalytic activity of TiO2-based nanomaterials is widely investigated due to the tentative of their industrialization as environmental photocatalysts and their inherently low solar spectrum sensitivity and rapid recombination of charge carriers. Coupling of oxygen-based bidentate diketone to nanocrystalline TiO2 represents a potential alternative for improving the holdbacks. Formation of TiO2-acetylacetone charge transfer complex (CTC) by sol-gel route results in a hybrid semiconductor material with photodegradation activity against toxic NOx gas. In this research, the influence of the chelating agent acetylacetone (ACAC) content on the CTC photocatalytic efficiency under visible light was evaluated. A high content of ACAC in the CTC is not a decisive factor for efficiency of photocatalytic reactions. In fact, the highest efficiency for NOx degradation (close to 100%, during 1 h of visible light exposure) was reported for the material calcined in air at 300 °C with the content of strongly bonded acetylacetone not higher than 3 wt.%. Higher calcination temperature (400 °C) left TiO2 almost completely depleted in ACAC, while at the highest applied temperature (550 °C) a portion of anatase was transformed into rutile and the sample is free of ACAC. The analyses pointed out that superoxide anion radical (O2−) plays an active role in photo-oxidation of NOx. Our findings indicate that this CTC has both high visible light spectral sensitivity and photocatalytic efficiency.
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- 2020
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11. Light-Emitting Porphyrin Derivative Obtained from a Subproduct of the Cashew Nut Shell Liquid: A Promising Material for OLED Applications
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Nayane Maria de Amorim Lima, Harold José Camargo Avila, Cleber Fabiano do Nascimento Marchiori, Samuel Gondim Sampaio, João Paulo Ferreira Mota, Viviane Gomes Pereira Ribeiro, Claudenilson da Silva Clemente, Giuseppe Mele, Marco Cremona, and Selma Elaine Mazzetto
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cashew nut shell liquid ,porphyrins ,photoluminescence ,electroluminescence ,OLEDs ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
In this work, the meso-tetra[4-(2-(3-n-pentadecylphenoxy)ethoxy]phenylporphyrin (H2P), obtained from the cashew nut shell liquid (CNSL), and its zinc (ZnP) and copper (CuP) metallic complexes, were applied as emitting layers in organic light emitting diodes (OLEDs). These compounds were characterized via optical and electrochemical analysis and the electroluminescent properties of the device have been studied. We performed a cyclic voltammetry analysis to determine the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energy levels for the porphyrins, in order to select the proper materials to assemble the device. H2P and ZnP presented fluorescence emission band in the red region, from 601 nm to 718 nm. Moreover, we verified that the introduction of bulky substituents hinders the π–π stacking, favoring the emission in the film. In addition, the strongest emitter, ZnP, presented a threshold voltage of 4 V and the maximum irradiance of 10 μW cm−2 with a current density (J) of 15 mA cm−2 at 10 V. The CuP complex showed to be a favorable material for the design of OLEDs in the infrared. These results suggest that the porphyrins derived from a renewable source, such as CNSL, is a promising material to be used in organic optoelectronic devices such as OLEDs.
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- 2019
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12. Functionalization of anatase nanoparticles with Glutaric acid and their photochemical and photocatalytic properties under visible light
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Jessica Gil-Londoño, Marco Cremona, Klaus Krambrock, Marcelo E.H. Maia da Costa, Lucas A. Almeida, and Bojan A. Marinkovic
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Process Chemistry and Technology ,Materials Chemistry ,Ceramics and Composites ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2023
13. Extrinsic Point Defects in TiO2–Acetylacetone Charge-Transfer Complex and Their Effects on Optical and Photochemical Properties
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Jessica Gil-Londoño, Klaus Krambrock, Raphaela de Oliveira, Marco Cremona, Marcelo E. H. Maia da Costa, and Bojan A. Marinkovic
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Inorganic Chemistry ,Physical and Theoretical Chemistry - Published
- 2023
14. Water Diffusion Effects at Gold–Graphene Interfaces Supporting Surface Plasmon Polaritons
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Quaid Zaman, null Tahir, Fernando Lazaro Freire, Ivan Shtepliuk, Andre N. Barbosa, Marcelo E. H. Maia da Costa, Cesar Augusto Diaz Mendoza, Jefferson F. D. F Araujo, Guilherme C. Concas, Marco Cremona, Zubair Ahmed, Omar Ginoble Pandoli, Ricardo Q. Aucelio, Victor Dmitriev, Karlo Q. da Costa, André Felipe S. Cruz, Gabriella Fibbi, Anna Laurenzana, Francesca Margheri, Anastasia Chillà, Francesca Scavone, Elena Frediani, Rajwali Khan, Nicola Daldosso, Elena Chistè, Gino Mariotto, Evelyn C. S. Santos, and Tommaso Del Rosso
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General Energy ,Physical and Theoretical Chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
15. Quenching of the Photoluminescence of Gold Nanoclusters Synthesized by Pulsed Laser Ablation in Water upon Interaction with Toxic Metal Species in Aqueous Solution
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null Tahir, Fernando Lazaro Freire Jr, Ricardo Q. Aucelio, Marco Cremona, Juliana da S. Padilha, Giancarlo Margheri, Quaid Zaman, Guilherme C. Concas, Mariana Gisbert, Sajjad Ali, Carlos A. T. Toloza, Yordy E. Licea, Tatiana D. Saint’Pierre, Rafael S. Carvalho, Rajwali Khan, Gino Mariotto, Nicola Daldosso, Geronimo Perez, and Tommaso Del Rosso
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pulsed laser ablation in water ,gold nanocluster ,photoluminescence ,mercury II ions ,Physical and Theoretical Chemistry ,Analytical Chemistry - Abstract
Sensors for the detection of heavy metal ions in water are in high demand due to the danger they pose to both the environment and human health. Among their possible detection approaches, modulation of the photoluminescence of gold nanoclusters (AuNCs) is gaining wide interest as an alternative to classical analytical methods based on complex and high-cost instrumentation. In the present work, luminescent oxidized AuNCs emitting in both ultraviolet (UV) and visible (blue) regions were synthesized by pulsed laser ablation of a gold target in NaOH aqueous solution, followed by different bleaching processes. High-resolution electron microscopy and energy-dispersive X-ray scattering confirmed the presence of oxygen and gold in the transparent photoluminescent clusters, with an average diameter of about 3 nm. The potentialities of the bleached AuNCs colloidal dispersions for the detection of heavy metal ions were studied by evaluating the variation in photoluminescence in the presence of Cd2+, Pb2+, Hg2+ and CH3Hg+ ions. Different responses were observed in the UV and visible (blue) spectral regions. The intensity of blue emission decreased (no more than 10%) and saturated at concentrations higher than 20 ppb for all the heavy metal ions tested. In contrast, the UV band emission was remarkably affected in the presence of Hg2+ ions, thus leading to signal variations for concentrations well beyond 20 ppb (the concentration at which saturation occurs for other ions). The limit of detection for Hg2+ is about 3 ppb (15 nmol/L), and the photoluminescence intensity diminishes linearly by about 75% up to 600 ppb. The results are interpreted based on the ligand-free interaction, i.e., the metallophilic bonding formation of Hg2+ and Au+ oxide present on the surface of the UV-emitting nanoclusters.
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- 2023
16. Enhanced Performance of All‐Solution Processed Multilayer OLEDs by Photoluminescence Lifetime Reduction of Cu(I) Complex Emitters Containing Chalcogenolate‐Diimine Ligands
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Alessandra Pereira, Marco Cremona, Giliandro Farias, Cristian A. M. Salla, Welber G. Quirino, Cristiano Legnani, Ivan H. Bechtold, and Bernardo de Souza
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Inorganic Chemistry ,Reduction (complexity) ,Photoluminescence ,Chemistry ,OLED ,Photochemistry ,Phosphorescence ,Diimine ,Solution processed - Published
- 2021
17. Biosubstrates Obtained from Gellan Gum for Organic Light-Emitting Diodes
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I. O. Maciel, Omar Pandoli, Marco Cremona, Cristiano Legnani, Tais de Cassia Ribeiro, Thales A. Faraco, Benjamin Fragneaud, Hernane da Silva Barud, Welber G. Quirino, Halice de O. X. Silva, Universidade Federal de Juiz de Fora (UFJF), Universidade de Araraquara (UNIARA), Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), and Universidade Estadual Paulista (Unesp)
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Organic electronics ,Materials science ,Nanotechnology ,Substrate (electronics) ,Biocompatible material ,Environmentally friendly ,Gellan gum ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,OLED ,chemistry ,biopolymer ,Materials Chemistry ,Electrochemistry ,organic light-emitting diode ,biosubstrate ,Electronics ,gellan gum - Abstract
Made available in DSpace on 2021-06-25T11:03:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Nowadays, flexible organic electronics are under intense investigation for environmentally friendly and biocompatible applications. One of the main components of electronic devices is the substrate, which gives support for building devices. There is great interest in the scientific community for the development of biocompatible and biodegradable substrates for the manufacture of these kinds of devices, aiming at technological and medical applications. In this work, we produced a flexible and transparent biosubstrate based on a gellan gum polymer by a solvent casting method to manufacture flexible organic light-emitting diodes (FOLEDs). The gellan substrate exhibited optical transparency of about 78% at 550 nm and 80% at 900 nm. In addition, the optimized indium tin oxide (ITO)/SiO2-coated gellan substrate exhibited a resistivity of 2.8 × 10-4 ω·cm and a sheet resistance of 11.2 ω/sq. These values are better or equal to those found in the literature for similar biosubstrates. Finally, the fabricated FOLEDs exhibited a maximum luminance of about 2327 cd/m2 and the current efficiency reached a maximum value of 2.9 cd/A. These characteristics reveal that this biosubstrate has interesting potential for applications in flexible green electronics, mainly due to its biocompatible properties and the results obtained by the developed FOLEDs. Grupo de Nanociência e Nanotecnologia (NANO) Departamento de Física Universidade Federal de Juiz de Fora (UFJF) Laboratório de Biopolímeros e Biomateriais (BIOPOLMAT) Departamento de Biotecnologia Universidade de Araraquara (UNIARA) Laboratório de Optoeletrônica Molecular (LOEM) Departamento de Física Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) Departamento de Química Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP)
- Published
- 2021
18. Sodium-Mediated Low-Temperature Synthesis of Monolayers of Molybdenum Disulfide for Nanoscale Optoelectronic Devices
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Victor Carozo, Braulio S. Archanjo, Arthur R. J. Barreto, Marco Cremona, Marcus V. O. Moutinho, Syed Hamza Safeer, M.E.H. Maia da Costa, F.L. Freire, and Omar Pandoli
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Molybdenum disulfide ,inorganic chemicals ,Fabrication ,Materials science ,genetic structures ,Sodium ,Molybdenum disulfide, 2D materials, low-temperature, APCVD, salt-mediated synthesis, CHEMICAL-VAPOR-DEPOSITION, TRANSITION-METAL, graphene ,chemistry.chemical_element ,chemistry.chemical_compound ,TRANSITION-METAL ,Monolayer ,General Materials Science ,Nanoscopic scale ,APCVD ,business.industry ,graphene ,technology, industry, and agriculture ,low-temperature ,salt-mediated synthesis ,2D materials ,eye diseases ,CHEMICAL-VAPOR-DEPOSITION ,chemistry ,Optoelectronics ,sense organs ,business - Abstract
Monolayers of molybdenum disulfide are of vital importance in the fabrication of optical and nanoelectronic devices. The development of thin and low-cost devices has increased the demand for synthe...
- Published
- 2021
19. Efficient Visible‐Light‐Excitable Eu 3+ Complexes for Red Organic Light‐Emitting Diodes
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Marco Cremona, Paula Brandão, Rafael dos Santos Carvalho, Biju Francis, Mariela M. Nolasco, Rute A. S. Ferreira, and Luís D. Carlos
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Inorganic Chemistry ,chemistry ,business.industry ,OLED ,Optoelectronics ,chemistry.chemical_element ,business ,Luminescence ,Europium ,Visible spectrum - Published
- 2020
20. Near-infrared absorbing cyanine dyes for all-organic optical upconversion devices
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Frank Nüesch, Marco Cremona, Rafael dos Santos Carvalho, Karen Strassel, Roland Hany, Rian E. Aderne, Sandra Jenatsch, Matthias Diethelm, and Cristiano Legnani
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Materials science ,business.industry ,Energy conversion efficiency ,Photodetector ,02 engineering and technology ,General Chemistry ,Photodetection ,Electroluminescence ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,7. Clean energy ,01 natural sciences ,Photon upconversion ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Materials Chemistry ,OLED ,Optoelectronics ,Quantum efficiency ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Visible spectrum - Abstract
The development of near-infrared (NIR) photodetection technologies is driven by emerging applications such as medical imaging or optical sensors for electronic displays and machine vision. An all-organic upconverter (OUD) is a device that converts incident NIR light directly into visible light and consists of a monolithic stack of a NIR organic photodetector (OPD) and a visible organic light-emitting diode (OLED). We present OUDs that consist of NIR heptamethine cyanine dyes/C60 fullerene OPDs and a fluorescent tris(8-hydroxyquinolinato)aluminium (Alq3) OLED. The device metrics of performance are a high external quantum efficiency (EQE) of 43% of the OPD part and an OUD luminance turn-on at low bias voltages of 2 V. The dynamic response of the photocurrent and luminance is linear over a NIR light range corresponding to 26 dB. These OUDs upconvert NIR light at 830 nm to green light with a photon-to-photon conversion efficiency of 0.61%, close to the expected maximum.
- Published
- 2019
21. Monolayer of silica nanospheres assembled onto ITO-coated glass substrates by spin-coating
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Rafael Miguel Sábio, A M de Aguiar, I. O. Maciel, Sidney José Lima Ribeiro, N A Yoshioka, Welber G. Quirino, Cristiano Legnani, Marco Cremona, T A Faraco, H da S Barud, Benjamin Fragneaud, Universidade Federal de Juiz de Fora (UFJF), Universidade de Araraquara (UNIARA), Universidade Estadual Paulista (Unesp), and Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
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SiO2 nanospheres ,Spin coating ,Materials science ,Mechanical Engineering ,Colloidal silica ,Bioengineering ,Optical transmittance ,02 engineering and technology ,General Chemistry ,Substrate (electronics) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Silica nanospheres monolayer ,Chemical engineering ,Average size ,Mechanics of Materials ,Electrical resistivity and conductivity ,Monolayer ,ITO substrates ,General Materials Science ,Electrical and Electronic Engineering ,0210 nano-technology - Abstract
Made available in DSpace on 2021-06-25T11:03:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-14 In this work, we synthesized colloidal silica nanospheres with an average size of 400 nm through the modified Stöber method and successfully fabricated an ordered close-packed silica nanosphere monolayer onto ITO-coated glass substrates using a three-step spin-coating method. ITO films showed resistivity comparable to that of commercial ITO and the silica nanosphere monolayer-coated ITO/glass substrate exhibited good optical transmittance in the visible (550 nm) and near-infrared (900 nm) regions of 62% and 82%, respectively. The results suggest that this monolayer can be used in optoelectronic devices to enhance efficiency in photovoltaic cells. Grupo de Nanociência e Nanotecnologia (NANO) Departamento de Física Universidade Federal de Juiz de Fora (UFJF) Laboratório de Biopolímeros e Biomateriais (BIOPOLMAT) Departamento de Biotecnologia Universidade de Araraquara (UNIARA) Departamento de Física Universidade Federal de Juiz de Fora (UFJF) Institudo de Química Universidade Estatual Paulista Julio de Mesquita Filho (UNESP) Laboratório de Optoeletrônica Molecular (LOEM) Departamento de Física Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) Faculdade de Ciências Farmacêuticas Universidade Estatual Paulista Julio de Mesquita Filho (UNESP) Institudo de Química Universidade Estatual Paulista Julio de Mesquita Filho (UNESP) Faculdade de Ciências Farmacêuticas Universidade Estatual Paulista Julio de Mesquita Filho (UNESP)
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- 2021
22. Self-Supported Smart Bacterial Nanocellulose–Phosphotungstic Acid Nanocomposites for Photochromic Applications
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Sidney José Lima Ribeiro, Cristiano Legnani, Hernane da Silva Barud, Sérgio Hiroshi Toma, Monica A. S. Alencar, Benjamin Fragneaud, Assis Vicente Benedetti, Koiti Araki, Moliria V. Santos, Marcelo Nalin, I. O. Maciel, Marco Cremona, Celso Molina, Universidade Estadual Paulista (Unesp), Universidade de Araraquara, Universidade de São Paulo (USP), Universidade Federal de Juiz de Fora (UFJF), Federal University of São, and Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)
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Technology ,Materials science ,Materials Science (miscellaneous) ,Oxide ,bacterial nanocellulose ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Nanocellulose ,Photochromism ,chemistry.chemical_compound ,Keggin structure ,phosphotungstic acid ,electrochromism ,polyoxometalates ,Phosphotungstic acid ,Nanocomposite ,021001 nanoscience & nanotechnology ,photochromism ,0104 chemical sciences ,Membrane ,chemistry ,Chemical engineering ,Electrochromism ,0210 nano-technology - Abstract
Made available in DSpace on 2021-06-25T11:03:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-13 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Instituto Nacional de Fotônica Bacterial nanocellulose (BNC) is a natural biopolymer obtained by gram-negative bacteria by means of a green and inexhaustible biotechnological process using glucose as producing source. BCN hydrogels is formed by cellulose nanofibrils that maintain an open network structure, an ideal matrix to produce new class of organic-inorganic nanocomposites (OIN) for multifunctional applications. The polyoxometalates (POMs) are complex molecules with several metallic ions sharing oxide ions, forming a highly symmetrical metal oxide cluster. Phosphotungstic acid (PWA), H3PW12O40 photoreduction process activated under ultraviolet irradiation, promoting color change. In this work, photochromic organic-inorganic nanocomposites were prepared by soaking phosphotungstic acid (H3PW12O40) in wet BNC membranes mats at room temperature. Semi-transparent and free-standing BNC/PWA nanocomposite with paper-like aspect were obtained. BNC network was able to control, stabilize and disperse PWA particles in a narrow nanometric distribution, and FTIR spectra indicated that the primary Keggin structure was also preserved in the nanocomposites, independently on the PWA content. The nanoparticles present a narrow distribution of around 16 nm, independently on the PWA concentration. BNC/PWA nanocomposites showed reversible photochromic behavior characteristic of the equilibrium between different tungsten oxidation states. PWA reduction (W6+→ W5+) and organic matrix oxidation is proposed to occur through a radical process involving the interaction of one electron from the oxygen atom of the PWA and one hydrogen from BNC matrix. The photochromic effect vanishes almost completely after 5 h. This mechanism is real in the presence of oxygen, however, if the membranes are left in nitrogen or under vacuum the blue color remains longer than 45 days. Photo-electrochemical behavior was studied by spectroelectrochemistry measurements. It is worth noting that all processes were still reversible in the timescale of the experiment and color changes were observed in several cycles. Institute of Chemistry São Paulo State University (UNESP) Laboratório de Biopolímeros e Biomateriais (BioPolMat) Universidade de Araraquara Instituto de Química – Universidade de São Paulo USP Departamento de Física Instituto de Ciências Exatas Universidade Federal de Juiz de Fora (UFJF) Deparment of Chemistry Federal University of São Departamento de Física Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) Institute of Chemistry São Paulo State University (UNESP) FAPESP: 2013/07793-6 FAPESP: 2013/24725-4 FAPESP: 2014/12424-2 FAPESP: 2016/11591-8 FAPESP: 2018/25512-8 FAPESP: 2020/04509-9 Instituto Nacional de Fotônica: 407822/2018-6
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- 2021
23. Recent advances with optical upconverters made from all-organic and hybrid materials
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Marco Cremona, Karen Strassel, and Roland Hany
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Materials science ,lcsh:Biotechnology ,quantum dots ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,near-infrared ,01 natural sciences ,mu-m ,lcsh:TP248.13-248.65 ,lcsh:TA401-492 ,Medical imaging ,General Materials Science ,photodetector ,NIR imaging ,up-conversion devices ,narrow-band ,organic light-emitting device ,light-emitting-diodes ,layer ,Near-infrared spectroscopy ,Optical, Magnetic and Electronic Device Materials ,40 Optical, magnetic and electronic device materials ,converter ,204 Optics / Optical applications ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,detectivity polymer photodetectors ,Narrow band ,Upconverter ,efficiency ,lcsh:Materials of engineering and construction. Mechanics of materials ,0210 nano-technology ,Hybrid material ,Organic light emitting device - Abstract
The growing interest in near-infrared (NIR) imaging is explained by the increasing number of applications in this spectral range, which includes process monitoring and medical imaging. NIR-to-visible optical upconverters made by integrating a NIR photosensitive unit with a visible emitting unit convert incident NIR light to visible light, allowing imaging of a NIR scene directly with the naked eye. Optical upconverters made entirely from organic and hybrid materials – which include colloidal quantum dots, and metal-halide perovskites – enable low-cost and pixel-free NIR imaging. These devices have emerged as a promising addition to current NIR imagers based on inorganic semiconductor photodiode arrays interconnected with read-out integrated circuitry. Here, we review the recent progress in the field of optical upconverters made from organic and hybrid materials, explain their functionality and characterization, and identify open challenges and opportunities., GRAPHICAL ABSTRACT 10.1080/14686996.2019.1610057-UF0001
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- 2019
24. Efficient terbium complex based on a novel pyrazolone derivative ligand used in solution-processed OLEDs
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Adailton J. Bortoluzzi, Marco Cremona, Ivan H. Bechtold, Cristian A. M. Salla, Caroline Arantes, Hugo Gallardo, Edivandro Girotto, and Alessandra Pereira
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Lanthanide ,Materials science ,Biophysics ,Pyrazolone ,chemistry.chemical_element ,Terbium ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,medicine ,OLED ,Ligand ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Combinatorial chemistry ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Solution processed ,chemistry ,Quantum efficiency ,0210 nano-technology ,Derivative (chemistry) ,medicine.drug - Abstract
Lanthanide organic complexes have high color purity with 100% theoretical internal quantum efficiency, making them good candidates for applications in organic light emitting devices. However, highly efficient and stable solution-processed devices based on terbium complexes have not been reported yet. Here, we present a solution-processed OLED using a novel terbium complex based on pyrazolone derivative ligand with pronounced efficiency. The device with co-host of 70% TcTa and 30% OXD-7 showed low turn-on voltage of 2.30 V, maximum current efficiency of 17.16 cd A−1 and external quantum efficiency of 7.15% at 1000 cd m−2. In addition, presenting a reduced roll-off efficiency compared to other reported terbium complex devices. This high efficiency for solution-processed Tb-based OLEDs clearly indicates the potential application of this Tb-complex in display applications.
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- 2019
25. Thermoelastic pulsed laser ablation of silver thin films with organic metal–SiO2 adhesion layer in water: application to the sustainable regeneration of glass microfluidic reactors for silver nanoparticles
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null Tahir, Omar Ginoble Pandoli, Quaid Zaman, Guilherme C Concas, Mariana Gisbert, Marco Cremona, Fernando Lazaro Freire, Isabel C S Carvalho, Pedro H C Bevilaqua, Druval Santos de Sá, Alexandre Pinto Canellas, Vinicius Mattoso, and Tommaso Del Rosso
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General Physics and Astronomy - Abstract
The synthesis of metal nanoparticles (NPs) using microfluidic reactors has become a major method for limiting reagent consumption and achieve a precise control of the morphological properties. Failure in realizing the reproducibility of the results is mostly associated with the accumulation of metallic nanostructures on the walls of the microfluidic devices, periodically removed by acid treatment. In this study, we show that ns-pulsed laser ablation (PLA) in water can be a safe, effective, and green method for the regeneration of clogged microfluidic reactors. The effect of the laser-pulse fluence on the removal of metallic nanostructures was studied for the first time on silver (Ag) thin films with a thickness of 50 nm deposited over SiO2 substrates, using 3-mercaptopropyl trimethoxysilane as a chemical adhesion layer. As point of novelty, the experimental results show that at low fluence (F −2), ablation is principally caused by delamination of the thin film associated with the thermoelastic force while thermal processes inducing phase conversion of the metal dominate at higher fluence. Low-fluence regimes are better suited for the single-pulse removal of the nanomaterial, whereas in high F regimes, we observed melting and recondensation of the metal on the SiO2 surface so that multiple pulse interactions were necessary for complete ablation of the thin film. For the delamination and the phase transformation processes, the threshold fluences were 3.7 × 10−2 and 7.0 × 10−2 J cm−2, respectively. The experimental setup in the thermoelastic PLA regime was applied to unclog glass microfluidic devices used for synthesizing citrate-stabilized AgNPs. Using this simple and easily achievable laser-scanning experimental configuration, we demonstrated that PLA in water is a reliable and efficient technique, with results comparable to acidic treatment in terms of efficiency and time necessary for the complete removal of the Ag nanomaterial.
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- 2022
26. Emission redshift in DCM2-doped Alq3 caused by nonlinear Stark shifts and Förster-mediated exciton diffusion
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Bruno A. C. Horta, Carlos A. Achete, Marco Cremona, Graziâni Candiotto, Rodrigo B. Capaz, Marcelo De Cicco, Ronaldo Giro, and Flávia P. Rosselli
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Physics ,Dopant ,Band gap ,Exciton ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redshift ,symbols.namesake ,Dipole ,Stark effect ,0103 physical sciences ,symbols ,Density functional theory ,Atomic physics ,010306 general physics ,0210 nano-technology ,HOMO/LUMO - Abstract
Organic light-emitting diode (OLED) devices in the archetype small-molecule fluorescent guest-host system tris(8-hydroxyquinolinato) aluminum ($\mathrm{Al}{\mathrm{q}}_{3}$) doped with 4-(dicyanomethylene)-2-methyl-6-julolidyl-9-enyl-4H-pyran (DCM2) displays a redshift in light-emission frequency which is extremely sensitive to the dopant concentration. This effect can be used to tune the emission frequency in this particular class of OLEDs. In this work, a model is proposed to describe this effect using a combination of density functional theory quantum-chemical calculations and stochastic simulations of exciton diffusion via a F\"orster mechanism. The results show that the permanent dipole moments of the $\mathrm{Al}{\mathrm{q}}_{3}$ molecules generate random electric fields that are large enough to cause a nonlinear Stark shift in the band gap of neighboring DCM2 molecules. As a consequence of these nonlinear shifts, a non-Gaussian probability distribution of highest occupied molecular orbital to lowest unoccupied molecular orbital (HOMO-LUMO) gaps for the DCM2 molecules in the $\mathrm{Al}{\mathrm{q}}_{3}$ matrix is observed, with long exponential tails to the low-energy side. Surprisingly, this probability distribution of DCM2 HOMO-LUMO gaps is virtually independent of DCM2 concentration into the $\mathrm{Al}{\mathrm{q}}_{3}$ matrix, at least up to a fraction of 10%. This study shows that this distribution of gaps, combined with out-of-equilibrium exciton diffusion among DCM2 molecules, is sufficient to explain the experimentally observed emission redshift.
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- 2020
27. Novel scanning magnetic microscopy method for the characterization of magnetic nanoparticles
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Marco Cremona, Oswaldo Baffa, Gino Mariotto, F.L. Freire, Tahir, Tommaso Del Rosso, Antonio C. Bruno, Quaid Zaman, Soudabeh Arsalani, Cleanio Luz-Lima, Jefferson F.D.F. Araujo, and Leonardo A. F. Mendoza
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IRON-OXIDES ,Materials science ,SURFACE ,Magnetometer ,Analytical chemistry ,CORROSION PRODUCTS ,02 engineering and technology ,FILMS ,01 natural sciences ,law.invention ,Magnetization ,RAMAN-SPECTROSCOPY ,law ,0103 physical sciences ,Microscopy ,Saturation (magnetic) ,MAGNETOMETER ,010302 applied physics ,ANISOTROPY ,Demagnetizing field ,equipment and supplies ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Remanence ,Magnetic nanoparticles ,0210 nano-technology ,human activities ,Superparamagnetism - Abstract
In this paper, a new method is presented for the magnetic characterization of nanoparticles that is especially suitable for samples with a low mass, on the order of tens of micrograms. We investigated the magnetic and morphological properties of the colloidal dispersions of iron oxide magnetic nanoparticles that were synthesized by two methods: chemical precipitation (co-precipitation) and pulsed laser ablation in liquid (PLA). We measured the stray field generated above the samples by scanning magnetic microscopy (SMM) and used a nonstandard model to obtain the magnetization of the nanoparticles. We assessed the performance of the method by comparing the magnetization curves with measurements obtained using commercial magnetometers. The errors in the saturation and remanent magnetization were found to be approximately ±0.18 Am2/kg and ±0.6 Am2/kg, respectively. As the samples exhibited a superparamagnetic state, we also used the magnetization curves to estimate the average size of the synthesized nanoparticles, which were found to be consistent with the results obtained using other techniques.
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- 2020
28. Bright neodymium complexes for efficient near infra-red organic light emitting diodes
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Zubair Ahmed, Harold C. Avila, Rafael S. Carvalho, Jiang Kai, J. A. L. C. Resende, Elisa Bandini, Andrea Barbieri, Marco Cremona
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- 2020
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29. Room temperature molecular electrophosphorescence detection in organic LEDs with (Gd, Eu)-β-diketonate complexes blend
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Marco Cremona, Hermi F. Brito, and R. Reyes
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Materials science ,Fabrication ,Gadolinium ,chemistry.chemical_element ,02 engineering and technology ,Electroluminescence ,010402 general chemistry ,01 natural sciences ,Ion ,Inorganic Chemistry ,OLED ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Spectroscopy ,LUMINESCÊNCIA ,Ligand ,Organic Chemistry ,Intermolecular force ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,chemistry ,Physical chemistry ,0210 nano-technology ,Europium - Abstract
In this work is reported the fabrication and characterization of the triple-layer electroluminescent organic devices using a mixture of the gadolinium and europium β-diketonate complexes [GdxEuy(TTA)3 (TPPO)2] as emitting layer. The OLED devices contained the 1-(3-methylphenyl)-1,2,3,4-tetrahydroquinoline-6-carboxyaldehyde-1,1′-diphenylhydrazone (MTCD) as hole-transporting layer and tris(8-hydroxyquinoline aluminum) (Alq3) as electron transporting layer. The electroluminescence spectra present emission narrow bands from 5D1 → 7F1,2 and 5D0 → 7F0,1,2,3,4 transitions characteristics of the Eu3+ ion. These sharp lines are overlapped with a broad band attributed to the electrophosphorescence due to the T1 → S0 transition from TTA ligand. The intermolecular energy transfer from Gd-chelate to Eu-chelate is discussed based on this electrophosphorescence appearance.
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- 2018
30. Phenoxy-benzothiadiazole dyes: Synthesis, photophysical properties and preliminary application in OLEDs
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Felipe Miranda Valente, Davi F. Back, Marco Cremona, Alessandra Pazini, Jones Limberger, Ricardo Q. Aucélio, Harold C. Avila, Rian E. Aderne, and Luis Maqueira
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Photoluminescence ,Organic Chemistry ,Quantum yield ,02 engineering and technology ,Electroluminescence ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Biochemistry ,Fluorescence ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,PEDOT:PSS ,Drug Discovery ,Luminophore ,OLED ,0210 nano-technology ,Derivative (chemistry) - Abstract
The synthesis of a phenoxy-benzothiadiazole (BTD) derivative is reported for the first time. This derivative was employed as an intermediate in the obtention of two novel highly fluorescent aryl-phenoxy-BTD dyes. Their photophysical properties were evaluated in solution and the results indicate a strong intramolecular charge transfer (ICT) character in the excited state. The luminophore 3a, possessing a donor-BTD-phenoxide architecture, exhibits superior fluorescence quantum yield (0.67) than the designed acceptor-BTD-phenoxide dye (0.06). After electrochemical and photoluminescence characterization of thin films of 3a, an OLED with the configuration ITO/PEDOT:PSS/3a/TPBi/LiF/Al was constructed. This device displayed a green emission centered at 547 nm, with CIE coordinates of (0.40, 0.55). For comparison, an OLED using a previously reported luminescent BTD-pyridyl derivative was also constructed. The OLED made with the phenoxy-BTD derivative operated using less current density and led to higher irradiance and electrical stability, indicating the high potential of ArO-BTD dyes for future application in electroluminescent devices.
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- 2018
31. High hole-mobility of rrP3HT in organic field-effect transistors using low-polarity polyurethane gate dielectric
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Cristol de P. Gouvêa, Rodrigo B. Capaz, Zubair Ahmed, Marco Cremona, Cleber F. N. Marchiori, Pablo Serrano, Harold C. Avila, Cecília Vilani, and Arthur R. J. Barreto
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Electron mobility ,Materials science ,Condensed matter physics ,business.industry ,Gate dielectric ,02 engineering and technology ,General Chemistry ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Electric dipole moment ,Dipole ,Semiconductor ,Materials Chemistry ,Charge carrier ,Field-effect transistor ,Electrical and Electronic Engineering ,0210 nano-technology ,business - Abstract
We report unusually high charge carrier mobilities for regioregular poly(3-hexyltiophene) (rrP3HT) in organic field-effect transistors (OFETs) using polyurethane (PU) as dielectric layer. Our devices display hole mobilities up to 1.37 cm2/V in the saturation regime and an ON/OFF current ratio higher than 103, operating at voltages as low as −10 V, with a high IDS current of 1.5 μA. We assign the measured high mobilities mainly to the low density of randomly-oriented electric dipoles at the semiconductor/dielectric interface, which leads to a narrow energy distribution of the electronic levels available for charge transport in rrP3HT. This is confirmed by experimental and theoretical techniques: (1) temperature-dependent transport measurements for extraction of disorder-induced distribution of electronic levels; (2) density functional theory (DFT) calculations of electric dipole moments of PU; and (3) liquid contact-angle measurements for the dipolar component of dielectric surface tension.
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- 2018
32. Conformational Change on a Bithiophene-Based Copolymer Induced by Additive Treatment: Application in Organic Photovoltaics
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Marco Cremona, Camilla Karla Brites Queiroz Martins de Oliveira, Natasha A. D. Yamamoto, O. D. Lourenco, Lucimara S. Roman, Harold C. Avila, Cleber F. N. Marchiori, Leandro Benatto, M. G. E. da Luz, and Marlus Koehler
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chemistry.chemical_classification ,Electron mobility ,Conformational change ,Fullerene ,Materials science ,Organic solar cell ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Solvent ,General Energy ,Chemical engineering ,chemistry ,Polymer chemistry ,Copolymer ,Physical and Theoretical Chemistry ,0210 nano-technology ,Order of magnitude - Abstract
In recent years the use of solvent additives for fabrication of polymer-based solar cells has become an important procedure to induce morphological changes at the system nanoscale, a critical step to improve device performance. Yet the actual effects of those additives on the polymer’s backbone conformations (with coupled variations on the electronic structure) remain very elusive. By combining different experimental and theoretical techniques, we show that the use of the solvent additive 1,8-diiodooctane (DIO) might influence the conformation of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2) chains resulting in improved properties of the film. We correlate this conformational variation with the photovoltaic response of F8T2:fullerene(C60) devices prepared using different DIO concentrations. We find that the efficiency of the devices increases more than 100%, and the hole mobility in the F8T2 films increases almost 1 order of magnitude with the use of DIO. A comparison between experimental da...
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- 2017
33. Investigation of Tin(II)2,3-naphtalocyanine molecule used as near-infrared sensitive layer in organic up-conversion devices
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Alexandre Cuin, Cristiano Legnani, Rian E. Aderne, Mônica C. Melquíades, Welber G. Quirino, and Marco Cremona
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Materials science ,Fullerene ,Absorption spectroscopy ,Organic Chemistry ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Organic semiconductor ,chemistry ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Thin film ,0210 nano-technology ,Tin ,Absorption (electromagnetic radiation) ,Spectroscopy ,HOMO/LUMO - Abstract
In this work, a near infrared (NIR) sensitive molecule, Tin(II)2,3-naphthalocyanine (SnNc) was characterized by different techniques. UV–Vis spectroscopy and cyclic voltammetry were performed in order to determine the absorption spectrum, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies of this molecule deposited in form of thin films. We found energies of 5.0 ± 0.1 eV and 3.7 ± 0.1 eV for HOMO and LUMO, respectively. The charge carrier mobility was also investigated by space charge limit current technique showing values of μh (8.8 ± 0.1) x 10−5 cm2V−1s−1. SnNc alone or blended with fullerene was used as efficient NIR sensitive layer due to its absorption around 875 nm. The crystalline structure of SnNc was studied by X-ray powder diffraction, showing a monoclinic system and P21/c space group, with cell parameters a = (15.948 ± 6) A, b = (15.818 ± 2) A, c = (14.649 ± 1) A and β = (67.096 ± 6) A. Desorption/Ionization-Time of Flight Mass Spectrometry (LDI-TOFMS) technique was employed to obtain information of molecular structure of the SnNc in thin film, showing that the thin film of the SnNc has no dimer formation. Due to its absorption around 875 nm, SnNc blended with fullerene was used as efficient NIR sensitive layer in the fabrication of an organic up-conversion device. When the device is submitted to IR radiation, a gain of about 133% was observed in the luminous efficiency when compared to values without IR irradiation.
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- 2017
34. Luminescent Eu3+–dibenzoylmethanate complex with sulfoxide ligand as sensitizer applied to organic light- emitting diodes
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Hermi F. Brito, E. Niyama, Marco Cremona, Ercules E.S. Teotonio, and R. Reyes
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Photoluminescence ,Ligand ,Chemistry ,Mechanical Engineering ,Electroluminescence ,EURÓPIO ,Photochemistry ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Intersystem crossing ,OLED ,Emission spectrum ,Luminescence ,Phosphorescence ,Engineering (miscellaneous) - Abstract
In this work the synthesis, characterization and photoluminescent and electroluminescent behavior of the [Eu(DBM)₃(PTSO)₂] complex have been investigated. The emission spectrum of this Eu³⁺–β– diketonate complex show characteristics narrow bands arising from the ⁵D₀→⁷Fȷ (J = 0–4) transitions, which are split according to the selection rule for Cs, Cn or Cnv site symmetries. Triple and doublelayer organic light-emitting diodes (OLEDs) using NPB as hole transporting layer, Alq₃ as electron transporting layer and [Eu(DBM)₃(PTSO)₂] complex as emitting and electron transporting layer were grown and characterized. We found the presence of two concurrent mechanisms for the electroluminescent behavior: (1) the electroluminescence (EL) from the exciton-ligand-Eu³+ ion energy transfer, responsible for the EL narrow bands; and (2) the molecular electrophosphorescence with an initial energy transfer exciton-ligand and posterior intersystem crossing from the excited singlet S₁ to the triplet T state followed by molecular phosphorescence (T→S₀). The electroluminescent behavior of [Eu(DBM)₃(PTSO)₂] complex suggest that this complex is promising to applied at Light Conversion Molecular Devices (LCMDs) such as in OLED devices.
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- 2017
35. Near infrared organic light emitting devices based on a new erbium(<scp>iii</scp>) β-diketonate complex: synthesis and optoelectronic investigations
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Zubair Ahmed, Marco Cremona, Helmut I. Padilla-Chavarría, Jackson A. L. C. Resende, Rian E. Aderne, and Jiang Kai
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Quenching (fluorescence) ,business.industry ,General Chemical Engineering ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Electroluminescence ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Erbium ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Octahedral molecular geometry ,OLED ,symbols ,Optoelectronics ,0210 nano-technology ,business ,Raman spectroscopy ,Triphenylphosphine oxide - Abstract
An in situ reaction of two optoelectronically active organic ligands (anionic thenoyltrifluoroacetylacetone, tta−, and neutral triphenylphosphine oxide, tppo) with erbium(III) ion in the presence of a base yielded a new erbium complex, [Er(tta)3(tppo)]. The solid and solution structure of the complex was established by X-ray crystallography, NMR, ESI-MS, FTIR, TGA and Raman spectroscopy. They indicate that the Er(III) ion is coordinated to seven oxygen atoms of three tta ligands and one tppo ligand in a monocapped octahedral geometry. The Judd–Ofelt parameters of the complex were determined by a least squares fitting and dealt with its chemical structure. On UV excitation through ligand mediation, the complex shows the characteristic near-infrared emission of the corresponding Er(III) ion at 1534 nm. Furthermore, a near infra-red organic light emitting diode (NIR-OLED) was fabricated with structure: ITO/[N,N′-bis(naphthalen-2-yl)-N,N′-bis(phenyl)benzidine]/[Er(tta)3(tppo)]/[2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)]/LiF/Al. This device, with maximum applied voltage of 23 V, shows a total quenching of visible emission and electroluminescence in the C-band region (1534 nm) which is suitable for third communication window applications in fiber optics. Finally, an organic diode was fabricated to determine charge carrier mobility of the complex using a steady-state method.
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- 2017
36. Ytterbium β-diketonate complexes for near infra-red organic light-emitting devices
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Jiang Kai, Rian E. Aderne, Helmut I.P. Chavarria, Zubair Ahmed, and Marco Cremona
- Subjects
Ytterbium ,Lanthanide ,Materials science ,Doping ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Surfaces and Interfaces ,Electroluminescence ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Indium tin oxide ,chemistry ,Materials Chemistry ,OLED ,Physical chemistry ,0210 nano-technology ,Luminescence ,Ternary operation - Abstract
A series of NIR emitting novel ytterbium tris β-diketonate ternary complexes, [Yb(tta) 3 (L)]·H 2 O {tta = thenoyltrifluoroacetylacetone and L = dibenzyl sulphoxide (dbso), diphenyl sulphoxide (dpso) and benzoguinamine (bga)} was synthesised, and the photophysical and optoelectronic properties of their films were studied. Nuclear Magnetic Resonance (NMR) analysis indicates that the complexes are seven-coordinate which is a highly asymmetric structure enhancing the radiative transitions. It is an indicative of efficient energy transfer from coordinated ligands to Yb ion. The complexes were doped in Tris(4-carbazoyl-9-ylphenyl)amine (TcTa) organic matrix and the doped samples were used as the emitting layers to fabricate near-infrared organic light emitting diodes (NIR-OLEDs) with the structure: Indium tin oxide/{N,N′-bis(naphtalen-2-yl)-N,N′-bis(phenyl) benzidine} (25 nm)/[Yb-complexes] (10%): TcTa (40 nm)/(2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline) (15 nm)/tris(8-hydroxy-quinolinato) aluminium (10 nm)/LiF (0.5 nm)/Al (120 nm). The complex, [Yb(tta) 3 (dpso)]·H 2 O shows the highest electroluminescence (EL) efficiency with maximum irradiance of 22.48 μW/cm 2 and current density of 29.5 mA/cm 2 at 15 V. It indicates an improved EL performance over the reported devices based on the Yb (III) complexes. In view of electrical characteristics, the current-voltage responses were interpreted by using Mott–Gurney model which allows us to determine the carrier mobility of the complexes.
- Published
- 2016
37. Synthesis of a low-coordinate erbium (III) β-diketonate complex assembled by opto-electronically active 1,3-diphenyl-1,3-propanedione and triphenylphosphine oxide ligands
- Author
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Zubair Ahmed, Marco Cremona, Rian E. Aderne, Jiang Kai, and Jackson A. L. C. Resende
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Lanthanide ,Chemistry ,Ligand ,Inorganic chemistry ,Stacking ,02 engineering and technology ,Crystal structure ,Triclinic crystal system ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,Octahedron ,Materials Chemistry ,Physical and Theoretical Chemistry ,0210 nano-technology ,Single crystal ,Triphenylphosphine oxide - Abstract
A novel Er(III) β-diketonate complex, tris(dibenzoylmethanate)mono(triphenylphosphine oxide) erbium(III) or [Er(dbm)3(tppo)] was synthesised with dbm as a main sensitizer and tppo as a synergic ligand. The single crystal X-ray analysis reveals that the crystal structure of the complex is a triclinic centrosymmetric where Er(III) ion is coordinated to seven oxygen atoms; one O-atom from one tppo and six O-atoms from three dbm ligands. Shape-measure criterion measurements show that the complex possesses a distorted monocapped octahedron geometry, which facilitates the radiative transitions that is an indicative of efficient energy transfer from coordinated ligands to Er ion. The crystal structure is stabilised by the π–π stacking and CH/π interactions which lead to its high photo- and thermal stabilities. The complex was doped into a polymer matrix and the resulted material shows an enhanced luminescence intensity as well as full width at half maximum (fwhm) which allow its possible use for optical-amplification applications. Finally, a single layered organic diode was fabricated to determine charge carrier mobility (μ0) inside the complex. For this purpose, the Mott–Gurney model was used which gave sizable μ0 of 3.39 × 10−9 cm2/Vs (at
- Published
- 2016
38. Tuning emitting color of electroluminescent devices containing Tris(2-acyl-1,3-indandionate)aluminum(III) complexes as emitting layers
- Author
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Hermi F. Brito, Rian E. Aderne, Maria C. F. C. Felinto, Marco Cremona, Ercules E.S. Teotonio, Wagner M. Faustino, Israel F. Costa, Harold C. Avila, and Jandeilson de Lima Moura
- Subjects
chemistry.chemical_classification ,LUMINESCÊNCIA ,Materials science ,Absorption spectroscopy ,General Chemistry ,Electroluminescence ,Acceptor ,Coordination complex ,chemistry ,OLED ,Physical chemistry ,Fourier transform infrared spectroscopy ,Thermal analysis ,Luminescence - Abstract
In this study, a novel type of tris(2-acyl-1,3-indandione)-aluminum(III) coordination compounds of the general formula [Al(acind)3]H2O, where 2-acyl-1,3-indandione (acind), 2-acetyl-1,3-indandione (aind), 2-benzoyl-1,3-indandione (bind), and 4-methyl-2-benzoyl-1,3-indandione (mbind), were synthesized and characterized by elemental analysis (CHN), Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H NMR) spectroscopies, thermal analysis (TG/DTG and DTA), and optical absorption spectroscopy in the UV-Vis region. These compounds present remarkably high green luminescence in powder and in thin-film forms. However, when these compounds are applied in glass/ITO/β-NPB/spiro-2CBP/[Al(acind)3]/Al and glass/ITO/β-NPB/[Al(acind)3]/LiF/Al electroluminescent devices, where spiro-2CBP is 2,7-bis(carbazol-9-yl)-9,9-spirobifluorene and β-NPB is N,N’-bis(naphthalen-2-yl)-N,N’-bis(phenyl)-benzidine, the emission color tuned from green to red, reflecting a change from the direct charge recombination in the emitting layer of the [Al(acind)3] complexes to an exciplex-based emission in which [Al(acind)3] complexes and spiro 2-CBP acted as acceptor and donor, respectively. These results suggest that [Al(acind)3] complexes have potential applications as molecular light converter materials for fabricating new electroluminescent devices.
- Published
- 2019
39. Ecological biosubstrates obtained from onion pulp (Allium cepa L.) for flexible organic light-emitting diodes
- Author
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Diógenes dos Santos Dias, I. O. Maciel, Omar Pandoli, Thales A. Faraco, Robson Rosa da Silva, Cristiano Legnani, Clovis Augusto Ribeiro, Halice de O. X. Silva, Hernane da Silva Barud, Welber G. Quirino, Benjamin Fragneaud, Marco Cremona, Universidade Federal de Juiz de Fora (UFJF), Universidade de Araraquara (UNIARA), Universidade de São Paulo (USP), Universidade Estadual Paulista (Unesp), BioSmart Nanotechnology, and Pontifícia Universidade Católica Do Rio de Janeiro (PUC-Rio)
- Subjects
Electron mobility ,Materials science ,02 engineering and technology ,Flexible organic light-emitting diode ,010402 general chemistry ,01 natural sciences ,DIODOS ,Sputtering ,Electrical resistivity and conductivity ,biopolymer ,OLED ,General Materials Science ,biosubstrate ,Thin film ,Sheet resistance ,Allium cepa L ,business.industry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Indium tin oxide ,FOLED ,Optoelectronics ,Allium cepa L., biosubstrate, biopolymer, flexible organic light-emitting diode, FOLED ,0210 nano-technology ,business ,flexible organic light-emitting diode - Abstract
Made available in DSpace on 2020-12-12T02:23:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 A new biopolymer obtained from onion pulp (Allium cepa L.) was employed to produce a sustainable substrate for flexible organic light-emitting diodes (FOLEDs). Indium tin oxide (ITO) and SiO2 thin films were deposited by rf-magnetron sputtering onto these biosubstrates to obtain flexible, transparent, and conductive anodes, on top of which FOLEDs were produced. This new biomaterial exhibits an optical transparency of 63% at 550 nm. ITO films were optimized by varying rf power during deposition onto the biopolymers, and their electrical properties are comparable to the those of ITO grown on top of rigid substrates: a carrier concentration of -3.63 × 1021 cm-3 and carrier mobility of 7.72 cm2 V-1 s-1 for the optimized film. Consequently, the sheet resistance and resistivity of this ITO film were 8.92 ω sq-1 and 2.23 × 10-4 ω cm, respectively, hence allowing the production of FOLEDs. The A. cepa L. based FOLED was fabricated using CuPc, β-NPB, and Alq3 as organic layers, and it exhibited a maximum luminance of about 2062 cd m-2 at 16.6 V. The current efficiency reached a maximum value of 2.1 cd A-1 at 85.3 mA cm-2. The obtained results suggest the possibility to use these substrates for innovative biocompatible applications in optoelectronics, such as photodynamic therapy. Grupo de Nanociência e Nanotecnologia (NANO) Departamento de Física Universidade Federal de Juiz de Fora (UFJF) Laboratório de Biopolímeros e Biomateriais (BIOPOLMAT) Departamento de Química Universidade de Araraquara (UNIARA) Instituto de Física de São Carlos Universidade de São Paulo (USP) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP) BioSmart Nanotechnology Laboratório de Optoeletrônica Molecular (LOEM) Departamento de Física Pontifícia Universidade Católica Do Rio de Janeiro (PUC-Rio) Departamento de Química Pontifícia Universidade Católica Do Rio de Janeiro (PUC-Rio) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP)
- Published
- 2019
40. Transparent bacterial cellulose nanocomposites used as substrate for organic light-emitting diodes
- Author
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Sidney José Lima Ribeiro, I. O. Maciel, Marco Cremona, Vanessa L. Calil, Cristiano Legnani, José Maurício Almeida Caiut, Hernane da Silva Barud, Welber G. Quirino, UFJF, Inmetro, Universidade de Araraquara (Uniara), Universidade de São Paulo (USP), Universidade Estadual Paulista (Unesp), and PUC-Rio
- Subjects
010302 applied physics ,Materials science ,business.industry ,Doping ,FILMES FINOS ,Substrate (electronics) ,Sputter deposition ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Indium tin oxide ,chemistry.chemical_compound ,Semiconductor ,chemistry ,Bacterial cellulose ,0103 physical sciences ,OLED ,Optoelectronics ,Electrical and Electronic Engineering ,Thin film ,business - Abstract
Made available in DSpace on 2019-10-06T16:49:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 In this work, high transparent bacterial cellulose (HTBC) biocompatible membranes were produced to be used as substrates in organic light-emitting diodes (OLEDs). These multifunctional membranes are based on bacterial cellulose (BC) and an organic–inorganic sol, composed of boehmite (Boe) nanoparticles and epoxi modified siloxane (GTPS). In order to be used as substrates, BC/Boe-GPTS membranes were covered with silicon dioxide (SiO 2 ) and indium tin oxide (ITO) thin films deposited at room temperature using radio frequency (RF) magnetron sputtering. Visible light transmission improves to 88%, instead of 40% previously achieved. The electrical properties for HTBC/SiO 2 /ITO substrate shows that the ITO deposited films are n-type doped semiconductors with resistivity of 2.7 × 10 −4 Ω cm, carrier concentration of − 1.48 × 10 21 cm −3 , and mobility of 15.2 cm 2 V −1 s −1 . These values are comparable to those of commercial ITO deposited onto glass substrates. After the characterization of the HTBC film, we used it as a substrate for the fabrication of a small molecule organic light-emitting diode OLED. The maximum efficiencies obtained were 1.95 cd/A and 1.68 cd/A for the reference OLED and the HTBC OLED, respectively. The HTBC OLED efficiency is then around 86% of the standard ITO-based OLED. This is clearly a good improvement, since previous BC-based simple architecture devices without Boe-GPTS have an efficiency 50% smaller than that of the standard OLED. Laboratório de Eletrônica Orgânica Departamento de Física Universidade Federal de Juiz de Fora UFJF Divisão de Metrologia de Materiais (DIMAT) Inmetro Laboratório de Biopolímeros e Biomateriais – BioPolMat Universidade de Araraquara (Uniara) Departamento de Química Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Universidade de São Paulo Instituto de Química Universidade Estadual Paulista UNESP Laboratório de Optoeletrônica Molecular Departamento de Física Pontifícia Universidade Católica do Rio de Janeiro PUC-Rio Instituto de Química Universidade Estadual Paulista UNESP
- Published
- 2019
41. Light-Emitting Porphyrin Derivative Obtained from a Subproduct of the Cashew Nut Shell Liquid : A Promising Material for OLED Applications
- Author
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Marco Cremona, Selma Elaine Mazzetto, Giuseppe Mele, Nayane Maria de Amorim Lima, Harold C. Avila, Cleber F. N. Marchiori, Viviane Gomes Pereira Ribeiro, Claudenilson da Silva Clemente, João Paulo Ferreira Mota, Samuel Gondim Sampaio, Lima, N. M. A., Avila, H. J. C., Marchiori, C. F. N., Sampaio, S. G., Mota, J. P. F., Ribeiro, V. G. P., Clemente, C. S., Mele, G., Cremona, M., and Mazzetto, S. E.
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Materials science ,Shell (structure) ,chemistry.chemical_element ,02 engineering and technology ,Zinc ,Electroluminescence ,010402 general chemistry ,porphyrins ,lcsh:Technology ,01 natural sciences ,Article ,electroluminescence ,chemistry.chemical_compound ,OLED ,General Materials Science ,lcsh:Microscopy ,lcsh:QC120-168.85 ,lcsh:QH201-278.5 ,lcsh:T ,OLEDs ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Porphyrin ,Copper ,0104 chemical sciences ,chemistry ,lcsh:TA1-2040 ,Alkoxy group ,lcsh:Descriptive and experimental mechanics ,photoluminescence ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,cashew nut shell liquid ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,lcsh:TK1-9971 ,Den kondenserade materiens fysik ,Derivative (chemistry) ,Nuclear chemistry - Abstract
In this work, the meso-tetra[4-(2-(3-n-pentadecylphenoxy)ethoxy]phenylporphyrin (H2P), obtained from the cashew nut shell liquid (CNSL), and its zinc (ZnP) and copper (CuP) metallic complexes, were applied as emitting layers in organic light emitting diodes (OLEDs). These compounds were characterized via optical and electrochemical analysis and the electroluminescent properties of the device have been studied. We performed a cyclic voltammetry analysis to determine the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energy levels for the porphyrins, in order to select the proper materials to assemble the device. H2P and ZnP presented fluorescence emission band in the red region, from 601 nm to 718 nm. Moreover, we verified that the introduction of bulky substituents hinders the &pi, &ndash, &pi, stacking, favoring the emission in the film. In addition, the strongest emitter, ZnP, presented a threshold voltage of 4 V and the maximum irradiance of 10 &mu, W cm&minus, 2 with a current density (J) of 15 mA cm&minus, 2 at 10 V. The CuP complex showed to be a favorable material for the design of OLEDs in the infrared. These results suggest that the porphyrins derived from a renewable source, such as CNSL, is a promising material to be used in organic optoelectronic devices such as OLEDs.
- Published
- 2019
42. Development of Conformable Substrates for OLEDs Using Highly Transparent Bacterial Cellulose Modified with Recycled Polystyrene
- Author
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Cristiano Legnani, Arthur R. J. Barreto, Robson Rosa da Silva, Hernane da Silva Barud, Sidney José Lima Ribeiro, Marco Cremona, Rafael dos Santos Carvalho, Fernando E. Maturi, Ariane V. S. Cebrian, Universidade Estadual Paulista (Unesp), Pontifícia Universidade Católica do Rio de Janeiro, University of Araraquara (UNIARA), Chalmers University of Technology, and UFJF
- Subjects
Materials science ,bacterial cellulose ,Renewable Energy, Sustainability and the Environment ,OLEDs ,biopolymers ,Conformable matrix ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Bacterial cellulose ,OLED ,recycled polystyrene ,Polystyrene ,General Environmental Science - Abstract
Made available in DSpace on 2021-06-25T11:03:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Bacterial cellulose (BC) is a biocompatible and nontoxic biopolymer that has been successfully used as a substrate for flexible organic light emitting diodes (OLEDs). Although BC membranes exhibit excellent mechanical properties and industrial scalability, they are semitransparent, which limits their performance. To improve the optical properties of BC membranes, methods such as the polymerization of different inorganic–organic hybrid materials and petrochemical derivative monomers have been considered; however, these methods require considerable time and effort. In this work, transparent BC membranes for conformable OLEDs substrates are fabricated by spray coating a solution of recycled petrochemical plastics, found in expanded foam package wastes, and d-limonene, which is a green solvent extracted from orange peels. This fabrication approach is highly scalable and can be considered a sustainable technique to develop high performance transparent substrates for photonic applications based on both recovered petrochemical polymers and naturally occurring biopolymers. In terms of the morphological and structural properties, the resulting transparent membranes exhibit a lower roughness than pristine BC. The resulting BC-PS composite is used as a substrate for OLED fabrication. The conformable OLEDs exhibit a current efficiency of up to 5 cd A−1 (16 000 cd m−2) and power density of ≈2.8 mW cm−2. Institute of Chemistry São Paulo State University – Unesp Departamento de Física Pontifícia Universidade Católica do Rio de Janeiro Grupo de Pesquisa em Biopolímeros e Biomateriais (BioPolMat) University of Araraquara (UNIARA) Department of Chemistry and Chemical Engineering Chalmers University of Technology Laboratório de Eletrônica Orgânica Departamento de Física Universidade Federal de Juiz de Fora UFJF Institute of Chemistry São Paulo State University – Unesp
- Published
- 2021
43. Synthesis and NIR-optoelectronic properties of a seven-coordinate ytterbium tris β-diketonate complex with C3 geometrical structure
- Author
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Jackson A. L. C. Resende, Rian E. Aderne, Marco Cremona, Zubair Ahmed, and Jiang Kai
- Subjects
Lanthanide ,Phosphine oxide ,Ytterbium ,Doping ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Benzidine ,0104 chemical sciences ,Ion ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Physical and Theoretical Chemistry ,0210 nano-technology ,Single crystal ,Ternary complex - Abstract
A low symmetry NIR emitting ytterbium (III) β-diketonate ternary complex with composition, [Yb(tta)3(tppo)]·H2O (tta = thenoyltrifluoroacetylacetone and tppo = triphenyl phosphine oxide) was synthesized and fully characterized. Single crystal X-ray analysis and shape measurement calculations indicate that the complex is a seven-coordinate and possesses distorted trigonal prism geometry with coordination polyhedra YbO7 where the Yb(III) ion is surrounded by seven oxygen atoms of three tta and one tppo ligands. It is a highly asymmetric structure enhancing the radiative transitions which is an indicative of efficient energy transfer from coordinated ligands to Yb ion. The complex was doped in a tris(4-carbazoyl-9-ylphenyl)amine (TcTa) matrix and used as an emitting layer to fabricate near-infrared organic light emitting device (NIR-OLED) with the structure: ITO/{N,N′-bis(naphtalen-2-yl)-N,N′-bis(phenyl) benzidine} (25 nm)/[Yb-complex] (10%): TcTa (40 nm)/BCP (15 nm)/Alq3 (10 nm)/LiF (0.5 nm)/Al (120 nm). The complex based NIR-OLED showed good EL efficiency with maximum irradiance of 19.29 μW/cm2 and current density of 27.3 mA/cm2 at 15 V. In view of electrical characteristics, the charge carrier mobility, μ0, of the complex was determined by using Mott–Gurney model which gave a sizable value of 4.50 × 10−8 cm2/Vs.
- Published
- 2016
44. Luminescent properties of a di-hydrazone derived from the antituberculosis agent isoniazid: Potentiality as an emitting layer constituent for OLED fabrication
- Author
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Rian E. Aderne, Marco Cremona, Rafaela S. Moraes, and Nicolás A. Rey
- Subjects
chemistry.chemical_classification ,Fabrication ,Materials science ,Dopant ,010405 organic chemistry ,Organic Chemistry ,Doping ,Hydrazone ,Electroluminescence ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,chemistry ,OLED ,Molecule ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Luminescence ,Spectroscopy - Abstract
Hydrazones constitute a class of compounds presenting azomethine R′R″N N CH R hydrogens, which show diverse properties and a wide range of applications. A hydrazone derived from the antituberculosis drug isoniazid, namely, N,N′-diisonicotinoyl-2-hydroxy-5-methylisophthalaldehyde hydrazone (DMD) was synthesized and chemically characterized. Its luminescent properties were also investigated, as well as the possibility of using this compound as a constituent of the emitting layer for the fabrication of OLEDs. Co-deposited devices were fabricated using the organic molecule BSBF as matrix and DMD as dopant. All the devices presented a broad electroluminescence band, in which it was possible to recognize the DMD emission along with emissions of some of the other organic layers. The best results were obtained with 35% DMD doping, achieving a luminance of about 35 cd/m2.
- Published
- 2016
45. Analysis of the dopant distribution in Co-deposited organic thin films by scanning transmission electron microscopy
- Author
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Marco Cremona, Carlos A. Achete, A.P.C. Campos, and Yolanda A. Paredes
- Subjects
Materials science ,Dopant ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Substrate (electronics) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry ,law ,Scanning transmission electron microscopy ,Materials Chemistry ,Phosphorescent organic light-emitting diode ,Iridium ,Thin film ,Phosphorescence ,Spectroscopy - Abstract
Organic light-emitting diodes using phosphorescent dyes (PHOLEDs) have excellent performance, with internal quantum efficiencies approaching 100%. To maximize their performance, PHOLED devices use a conductive organic host material with a sufficiently dispersed phosphorescent guest to avoid concentration quenching. Fac-tris(2-phenylpyridine) iridium, [Ir(ppy)3] is one of the most widely used green phosphorescent organic compounds. In this work, we used scanning transmission electron microscopy (STEM) equipped with HAADF (high-angle annular dark-field) and EDS (energy dispersive X-ray spectroscopy) detectors to analyze the distribution of the [Ir(ppy)3] concentration in the host material. This analysis technique, employed for the first time in co-deposited organic thin films, can simultaneously obtain an image and its respective chemical information, allowing for definitive characterization of the distribution and morphology of [Ir(ppy)3]. The technique was also used to analyze the effect of the vibration of the substrate during thermal co-deposition of the [Ir(ppy)3] molecules into an organic matrix.
- Published
- 2015
46. Chemical and structural modification of organic devices via focused ion-beams
- Author
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Marco Cremona, C. P. Gouvêa, and Harold C. Avila
- Subjects
chemistry.chemical_classification ,Materials science ,Analytical chemistry ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Focused ion beam ,0104 chemical sciences ,Ion ,Characterization (materials science) ,Organic semiconductor ,symbols.namesake ,chemistry ,symbols ,General Materials Science ,Absorption (chemistry) ,0210 nano-technology ,Raman spectroscopy ,Layer (electronics) - Abstract
In this study, we investigated the effects generated by ion bombardment on the charge transport properties of organic semiconductor devices. Focused ion beam (FIB) technology was used to induce the bombardment at different ion doses on poly(3-hexylthiophene) (rrP3HT) and poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) organic semiconductors. The characterization techniques demonstrated the presence of two regimes: at 2E13 and 2E14 doses. UV–Vis absorption, Raman spectroscopy and advanced electron microscopy analysis reveal the presence of a chemically and structurally modified layer approximately 40 nm thick. The results were confirmed by theoretical ion tracking simulation nearly 40–50 nm thick from the organic surface. The dependence of charge transport and ion bombardment was clearly evidenced by modifications in the charge carrier mobility that formed defects induced by the ion beams, such as degassing, cross-linking polymer chains, and the transformation of functional groups in the ion tracking region.
- Published
- 2020
47. Designing highly luminescent aryloxy-benzothiadiazole derivatives with aggregation-induced enhanced emission
- Author
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Jones Limberger, Felipe Miranda Valente, Luis Maqueira, Ricardo Q. Aucélio, Fabiano Severo Rodembusch, Marco Cremona, Fabiano da Silveira Santos, Davi F. Back, Arthur R. J. Barreto, Rafael dos Santos Carvalho, and Alessandra Pazini
- Subjects
Materials science ,Process Chemistry and Technology ,General Chemical Engineering ,Aryl ,Stacking ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Intramolecular force ,Acetone ,Radiative transfer ,OLED ,0210 nano-technology ,Luminescence - Abstract
A series of luminescent aryloxy-benzothiadiazole derivatives with architectures ArO-BTD-Ar’ and ArO-BTD-NAr’ were synthetized. The aim was to achieve a molecular design based on restriction of intramolecular rotation of the ArO- group associated to the presence of bulky aryl or N-aryl groups, which can avoid detrimental π-π stacking and favor radiative decays in the aggregated/solid state. In solution, these compounds showed fluorescence emission located in the blue to red regions with relative high fluorescence quantum yields (φFL = 0.27–0.74). For all ArO-BTD-Ar’ derivatives, emission enhancement was observed upon aggregation. The essential role of the ArO- group in the AIEEgenic ability was confirmed by comparing with Ar’-BTD-Ar’ analogs. Some solid ArO-BTD-Ar’ compounds displayed higher φFL than when in solution. Their aggregation-induced enhanced emission (AIEE) were corroborated by studies in water/acetone systems (I/I0 emission rations up to 7.7). Monocrystal X-ray analysis of selected compounds confirmed the twisted nature and absence of detrimental π-π stacking. The more emissive compound (φFL = 0.83) was applied as emitting material in a green OLED structure, presenting turn-on voltage around 3.5 V and luminance up to 1200 cd m−2, with a maximum current efficiency of 5.6 × 10−1 cd A−1 at 6.5 V.
- Published
- 2020
48. Understanding the effect of solvent additive in polymeric thin film: turning a bilayer into a bulk heterojunction-like photovoltaic device
- Author
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C. A. M. de Moraes, Marlus Koehler, Marco Cremona, J. A. Govatski, C. P. Gouvêa, Lucimara S. Roman, Cleber F. N. Marchiori, H. C. Avila, Leandro Benatto, and C. K. B. Q. M. Oliveira
- Subjects
chemistry.chemical_classification ,Materials science ,Acoustics and Ultrasonics ,Organic solar cell ,Bilayer ,Heterojunction ,Electron donor ,02 engineering and technology ,Photovoltaic effect ,Electron acceptor ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Acceptor ,Polymer solar cell ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,0210 nano-technology - Abstract
Here we report the effect of an additive solvent, the 1,8-diiodooctane (DIO) on the performance of a bilayer organic photovoltaic (OPV) device which active layer comprises the poly[2,7-(9,9-bis(2 ethylhexyl)-dibenzosilole)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PSiF-DBT) as the electron donor material and C60 as the electron acceptor material. We observed that when the donor layer was treated with 1% of DIO the power conversion efficiency (PCE) of the device increase 138.4% in relation to the device with a non-treated donor layer and 21.3% in relation to the device containing a donor layer submitted to a thermal annealed. The main effects that lead to this increase in PCE are the large interfacial area between donor and acceptor materials and the improved conductivity at low voltages. The increase in polymer surface roughness leads to a more effective PSiF-DBT/C60 interface for exciton dissociation. This effect, as well as the increase in the conductivity, raised the short circuit current density (JSC) to 13.89 mA/cm2 and PCE to 4.84%. Our conclusions are supported by morphological analysis, chemical cross-sectional evaluations with advanced microscopy techniques, charge mobility measurements as well as by theoretical simulations of the devices in which the changes on the donor/acceptor interfacial area were considered. The outcomes suggests that, solvent additives could be an alternative treatment to replace the thermal annealing which imposes further difficulties to perform the lab-to-manufacturing upscaling.
- Published
- 2020
49. Study of Dactylopius opuntiae and its electrical properties as thin film for application in organic devices
- Author
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Marco Cremona, Yolanda Angulo, Arthur R. J. Barreto, Harold C. Avila, Karla Vizuete, Stefania Llumiquinga, Kirsty Noboa, and Alexis Debut
- Subjects
Cochineal ,Materials science ,biology ,Band gap ,General Chemistry ,Electroluminescence ,Condensed Matter Physics ,biology.organism_classification ,law.invention ,Pigment ,PEDOT:PSS ,Chemical engineering ,law ,visual_art ,visual_art.visual_art_medium ,Phosphorescent organic light-emitting diode ,General Materials Science ,Thin film ,Luminescence - Abstract
In this work, we perform morphological and physicochemical studies of Dactylopius opuntiae (cochineal) with electron microscopy and explore their use as a transporting layer for organic electronic devices. The charge transport properties of this pigment were investigated through current-voltage measurements. The current-voltage characteristics have shown that the cochineal can be used as a hole-transporting layer (HTL) with mobility of 5.30 ± 0.03 × 10−4cm2V−1 s−1. Different analyses were realized on this pigment and the results were compared with other HTL organic compounds, as Poly(3,4-ethylene dioxy thiophene): poly(styrene sulfonate) (PEDOT:PSS). The results show that the cochineal pigment does not produce luminescence and has a band gap of 2.6 ± 0.2 eV with optical absorption in the visible range. The roughness of cochineal thin films was measured after filtering the solution with a value of 11.8 ± 0.2 nm. Cochineal and PEDOT:PSS were successfully used as HTL in the fabrication of a [Ir(fliq)2acac] based PHOLED. The results show an increase in the electroluminescent color purity emission due to the filtering action of the natural pigment when compared with the PEDOT:PSS based in this device.
- Published
- 2020
50. SPR sensors for monitoring the degradation processes of Eu(dbm)(3)(phen) and Alq(3) thin films under atmospheric and UVA exposure
- Author
-
T. Del Rosso, Quaid Zaman, Omar Pandoli, Marco Cremona, and Arthur R. J. Barreto
- Subjects
Materials science ,Photoluminescence ,Dibenzoylmethane ,Alq3 ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,01 natural sciences ,chemistry.chemical_compound ,Lanthanides ,beta-diketonate ,Thin film ,Spectroscopy ,Plasmon ,Degradation process of organic luminescent materials ,complexes ,Surface plasmon ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,chemistry ,UVA dosimeters ,SPR sensor ,Alq3, Degradation process of organic luminescent materials, Lanthanides, beta-diketonate, complexes, AFM, UVA dosimeters ,AFM ,0210 nano-technology ,Europium ,Refractive index - Abstract
The degradation processes of tris(8-hydroxyquinoline) (Alq3) and tris(dibenzoylmethane) mono(1,10-phenanthroline)europium(III) (Eu(dbm)3(phen)) thin films are investigated by the use of AFM, photoluminescence and SPR spectroscopy. The plasmonic sensors are operated both in air and nitrogen environments, where they are irradiated with controlled doses of UVA radiation. AFM results don’t reveal the formation of heterogeneous phases and crystallization under air exposure. The organic thin films change their refractive index under both types of exposure and act as a protective layer against oxidation for the SiO2/MPTS/metal interface of the plasmonic sensors. SPR measurements reveal a strict correlation between the refractive index increase and quenching of the photoluminescence of the organic thin films. The results are promising for the development of compact plasmonic UVA dosimeters in the surface plasmon coupled emission configuration (SPCE) with lanthanide β-diketonate complex materials (patent pending).
- Published
- 2018
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