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One of the important strategies for designing pure organic dyes is to improve the electron donating abilities of dye donors hence increase the intramolecular potential energy difference. In order to quantify the electron-donating capacity of organic units, we firstly propose a parameter donation ability (DA) value for evaluating the electron DA of organic units via theoretical calculation, by using of several fragments such as coplanar dithiophenyl pyrrole, triphenylamine (TPA), phenothiazine (PTZ) and cyanoacetic acid (CA) which is the research objects here. Inspired by the DA values of the above organic fragments, dye PSD-9, PSA-10 and PST-11 were designed and synthesized. Cyclic voltammetric (CV) measurements show that the DA values of dye PSA-10 and PST-11's donor increases when TPA and PTZ groups are introduced into PSD-9, hence HOMO level increases and the band-gap narrow down. This change is reflected in the absorption spectra: the maximum absorption wavelength of PSA-10 and PST-11 is 63 and 84 nm red-shifted compared with PSD-9. Similarly, the molar extinction coefficients of PSA-10 and PST-11 are increased by 34.7 × 103 and 14.7 × 103 M−1 cm−1, respectively. Combining a mesoporous titania film grafted by these dithiophenyl pyrrole dye with iodine electrolyte, an 4.2% and 4.8% power conversion effciency (PCE) is achieved for PSA-10 and PST-11 at an irradiance of the AM1.5G sunlight, with an significant increasing compared to PSD-9 with an PCE of 1.6%. The typical photocurrent density–voltage (J–V) test shows that the short circuit current of dye PSA-10 and PST-11 is much higher than that of PSD-9, which is the main reason for the improvement of PCE. The red-shift and stronger IPCE curve is the most advantageous evidence of the change of short circuit current. Furthermore, electrochemical impedance measurements is studied for exploring the changes of open-circuit voltage of PSA-10 and PST-11, the results infer that larger donor units and long alkyl chains can effectively increasing current density on photoanode, hence increase the open circuit voltage of the devices. [ABSTRACT FROM AUTHOR]

A novel Bi2MoO6/reduced graphene oxide/BiOBr (Bi2MoO6/RGO/BiOBr) composite was successfully synthesized via a facile solvothermal synthesis and precipitation method. The Bi2MoO6/RGO/BiOBr composite was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and photoelectrochemical measurements. The photocatalytic properties were explored for removal of methylene blue (MB) and norfloxacin (NFX) under visible-light irradiation. The Bi2MoO6/RGO/BiOBr composite exhibits the highest degradation rate compared with Bi2MoO6, BiOBr and Bi2MoO6/BiOBr composite, and that removal ratios of MB and NFX were 96.93% and 78.12%, respectively. A Z-scheme catalytic mechanism suitable for the system was proposed based on the results of UV–vis DRS, free radical trapping experiments and M–S carve analysis, in which RGO as an electronic medium can accelerate electron transfer. It is noteworthy that the close contact interface structure promotes the separation of electrons and holes and improves the photocatalytic performance. [ABSTRACT FROM AUTHOR]

The resent work reports synthesis of mixed metal oxides of FeLaO3 and FeNdO3 nanocomposites via Co-precipitation method, as effective photocatalyst. The synthesized metal oxides were characterized by Fourier transfer infrared (FT–IR) spectroscopy; X-ray diffraction pattern, and transmission electron microscopy. Alternating gradient force magnetometer illustrates magnetic behavior of mixed metal oxides of FeLaO3 and FeNdO3 nanocomposites. The photocatalytic property of FeLaO3 and FeNdO3 nanocomposites were evaluated using the photodegradation of methyl violet, and malachite green oxalate under ultraviolet light irradiation at various parameters such as temperature, pH of solution, the concentration of dyes, does of catalysts, and time of illumination of UV light. The results show that these nanocomposites have applicable magnetic and photocatalytic performance. [ABSTRACT FROM AUTHOR]

Size-tunable nanoparticles (NPs) for pristine cadmium sulfide (CdS) and iron (Fe)-doped (5, 10 and 15%) CdS were synthesized using facile chemical co-precipitation. Size-controlled NPs were prepared with thioglycolic acid (TGA) as the capping agent and their structural, optical, morphological and physiochemical evaluations were performed using X-ray diffraction (XRD), UV–visible spectroscopy, Raman spectroscopy, field emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR). XRD revealed single cubic phase of CdS and later broader peaks upon mixing of Fe, and intensive absorption was recorded in the visible regime upon doping with redshift. FESEM confirmed spherical nanoparticles of Fe–CdS, and Cd–S linkage along with other functional groups was recognized by FTIR. Cd1−xFexS (x = 0, 0.05, 0.10 and 0.15) powder was used as the photocatalyst for methylene blue (MB) degradation in visible light and catalyst in NaBH4's presence. The control CdS bleached MB faster than doped but doped CdS showed higher catalytic degradation. The Fe-doped CdS NPs showed superior catalytic potential compared to undoped CdS which suggests their use in dye industries, especially leather and tanneries. Additionally, NPs not only show superior catalytic characteristics but also help in cost reduction and complete removal of dyes for wastewater management. [ABSTRACT FROM AUTHOR]

Photoacoustic imaging (PAI) is a non-destructive biomedical imaging technology with broad application prospects. PAI combines the advantages of optical imaging and ultrasound imaging with high selectivity and deep penetration to overcome the high scattering limitation of light in tissues. This emerging technology also achieves high-resolution and high-contrast imaging of deep tissue in vivo. Recently, photoacoustic (PA) probes based on organic dyes have emerged prominently in biosensing and bioimaging due to their excellent optical properties and structural adaptability. This paper gives an outline of the basic PAI principles and focuses on the application of organic-dye-based PA probes for molecular detection and in vivo imaging. The advantages of PAI technology and the drawbacks of current PA probes are then summarized. Finally, the prospects for application are evaluated considering the potential challenges in the biomedical fields. [ABSTRACT FROM AUTHOR]

In this investigation, palladium nanoparticles were synthesized by green and inexpensive method using Nonpareil almond hull, as a reducing and stabilizing agent without using any toxic solvent or capping agents. In this protocol, two separate methods were used to immobilize Pd NPs on the surface of green-waste Nonpareil almond shell (NAS) and modified Nonpareil almond shell was obtained as an environmentally benign support. The green synthesized nanocatalysts were characterized by UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET), and transform electron microscopy (TEM). TEM images revealed that the Pd NPs immobilized on modified Nonpareil almond shell are spherical particles with average size of less than 20 nm without any agglomeration. In order to investigate the catalytic activity of green synthesized Nanocatalyst, it was used in the reduction of Methylene Blue (MB), Rhodamine 6G (R6G) and Methyl Orange (MO) at room temperature. The results showed that the modified nanocatalyst had a high catalytic activity in the reduction of these organic dyes. In addition, the nanocatalyst can be easily recycled and reused several times without losing its activity. [ABSTRACT FROM AUTHOR]

Herein, we developed a facile one-pot hydrothermal route to synthesize uniform functional Li2Si2O5 hydrate rod-like crystals. The growth of such unique anisotropic morphology underwent an in situ crystallization involving ordered attachment and Ostwald ripening of Li2SiO3 nanoparticles, and reactive transformation of Li2SiO3-to-Li2Si2O5 hydrate processes. The obtained Li2Si2O5 hydrate rods possessed a uniform size with a length of about 5 µm and a diameter of about 100–200 nm, indicating aspect ratio higher than 20 that reflected the anisotropic growth. The Li2Si2O5 hydrate rods exhibited excellent adsorption performance of methylene blue and the methylene blue-bearing Li2Si2O5 hydrate featured interesting photoluminescence performance of red emission at 675 nm compared with the reported value. The result endowed the Li2Si2O5 hydrate rods with a potential application as an optical probe for organic dye's recognition. [ABSTRACT FROM AUTHOR]

In this work, we reports preparation of novel TiO2/AgBr/PANI nanocomposite, as visible-light-driven photocatalyst via a convenient low-temperature method. The prepared sample was characterized by energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, Fourier transform infrared and UV–Vis diffuse reflectance spectroscopy techniques. The rhodamine B dye in aqueous solution was chosen as an environmental dye pollutant model. Photocatalytic activity for degradation of RhB increased from just 12.2% degradation with TiO2 to 43.6, 64.6 and 98.6% with TiO2/AgBr, TiO2/PANI and TiO2/AgBr/PANI after 140 min. The high activity of TiO2/AgBr/PANI nanocomposite could be attribute to more absorption in visible range, formation of heterojunction between counterparts and efficiently separation of the charge carriers, which was subsequently confirmed by photoluminescence spectroscopy and active spices trapping with different scavengers. Moreover, for the purpose of access the wide applications of the prepared samples, methylene blue and methyl orange were chosen as typical organic pollutants and degraded with prepared samples. The photostability and recyclability of TiO2/AgBr/PANI nanocomposite was investigated after five runs. [ABSTRACT FROM AUTHOR]

The present paper reports an unexplored simple, single step and cost effective green process for the preparation of highly stable silver nanoparticles (AgNPs) using Epilobium parviflorum (EP) extract and investigates their catalytic activity towards hazardous organic dyes, congo red (CR), rhodamine B (RhB), methyl orange (MO), methyl red (MR), and colorimetric sensing ability for Hg2+ ions in solutions. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR–FTIR) studies confirmed the capping and stabilization of the AgNPs by EP extract. X-ray diffraction (XRD) pattern showed face centered cubic structure for the AgNPs. Transmission electron microscopy (TEM) validated that the AgNPs are spherical in shape with narrow size distribution of 5.59 ± 1.12 nm. The results indicate that regardless of their good linear dynamic range (0.5–5.0 µM), detection limit (58.11 nM, 11.62 ppb) and selectivity for the accurate determination of Hg2+ ions, the AgNPs can be attractive choices for wastewater management systems. [ABSTRACT FROM AUTHOR]

A new material consisted of titanium dioxide microparticles photosensitized by organic dyes for generating the photodynamic effect is proposed and tested. The efficiency of using such a material for photopurifying water of organic pollution by daylight illumination is proven. [ABSTRACT FROM AUTHOR]

A series of novel push–pull-based D–π–A-containing organic dyes have been synthesized using triphenylamine and carbazole act as π-conjugated donor and cyanoacrylic acid acceptor as well as anchoring group for application of dye-sensitized solar cells. These organic dyes D1, D2 and D3 exhibited excellent photophysical, electrochemical properties, superior stoke shift, high thermal stabilities and sufficient HOMO–LUMO energy levels, which is facilitated to dye regeneration and effective injection of electron from the excited state of the dyes into the conduction band (TiO2). Our results suggested that carbazole π-bridge has an important role in the photovoltaic performance. The D1 and D2 dyes are planar linear structure, longer π-conjugated bridging units, when compared to the starburst structure of D3 organic dye. Moreover, the carbazole π-bridged conjugated D1 dye showed promising photovoltaic conversion efficiency (η) of 1.4%, Voc = 735 mV, Jsc = 2.7 mA/cm2, ff = 0.73 (fill factor), when compared with the conventional N719 and D5 organic dyes. [ABSTRACT FROM AUTHOR]

Co2TiO4/CoTiO3/Polyaniline ternary nano-hybrids were fabricated via sol–gel method and new gelling agent. The varied preparation factors like the type of calcination temperature, solvent and gelling agent were studied through the dimension and morphologies of final products. The photocatalytic activity of the Co2TiO4/CoTiO3/Polyaniline was verified via destruction of changing pollution like as diazinon, methylene blue, eosin Y, methyl orange, and phenol red. The maximum percentage of destruction of organic pollutions was found to be for diazinon (98.3%). The BET analysis demonstrated that the preparation of nano-hybrids in both of presence valine and of phenylalanine can increase surface from 1.05 m2/g to 13.50 m2/g. The obtained ternary nano-hybrids were characterized through EDX, TEM, XRD, DRS, VSM, SEM, and FT-IR. [ABSTRACT FROM AUTHOR]

Tandem solar cells were developed for improved efficiency in connection with perovskite solar cells and dye-sensitized solar cells. The organic dye based on thioindigo and N719 were applied in fabricating dye-sensitized solar cells as photosensitizers. We achieved an 8.77% and 10.54% efficiency tandem solar cell formed by a top perovskite solar cell and dye-sensitized solar cells based on organic dye and N719 for the bottom cell, respectively. The photovoltage of tandem solar cells was reported about 1.1 V, but the photocurrent was limited by the dye-sensitized solar cells and was about 12.8 mAcm−2. [ABSTRACT FROM AUTHOR]

Existing industrial titania production lines and their intermediate products are economically attractive precursors for synthesis of highly concentrated TiO2 coating sols and soluble nanopowders. Refluxing of aliphatic alcoholic TiOCl2 solutions (with up to 500 g TiO2/L) allows straightforward formation of nonaggregated anatase nanocrystals with size between 5 and 8 nm. Surface modification of these nanoparticles with organosilanes shifts the pH value of point of zero charge from initially 5.3 down to around 2.8. At appropriate Ti/Si ratios, complete suppression of the anatase ultraviolet (UV) photoactivity is possible. Furthermore, we address the optical and photocatalytic data of transparent nanocrystalline layers produced from superconcentrated ZnxTiyOz heterosols. Depending on the Zn/Ti ratio and processing temperature, colorless cubic c-ZnTiO3 and c-Zn2TiO4 spinel nanophases or coupled r-ZnTiO3-ilmenite/r-TiO2-rutile heterojunctions (Zn/Ti = 2/3) can be produced. The cubic spinel films are indirect semiconductors showing band gap transition of around 3.7 eV. In contrast, r-ZnTiO3-ilmenite films have slightly lower band gap of around 3.6 eV. Organic dye photodegradation studies reveal the highest catalytic activity for the coupled r-ZnTiO3-ilmenite/r-TiO2-rutile systems compared with colored (nitridated) or colorless cubic spinel film samples. [ABSTRACT FROM AUTHOR]

Rhodamine B (RhB), which has several industrial and chemical applications, is a harmful dye. It requires treatment prior to discharging for both environmental and societal safety. In this context, titania (denoted as DTS) supported different types of noble metal nanoparticles, with one percent weight per weight loading of metal. These were synthesized and were applied for RhB photodegradation. The synthesized photocatalysts were characterized by BET surface area, X-ray powder diffraction (XRPD), transmission electron microscopy (TEM), solid-state UV–Vis, H2-TPR study, CO-pulse chemisorption analysis. The activity of 1% noble metals/DTS for RhB photodegradation under UV irradiation follows the order of Pt/DTS > Pd/DTS > Ru/DTS > DTS. The most optimal activity of Pt/DTS could be attributed to its lowest reflectance and highest degree of absorbance of UV light, its smallest band gap energy (Eg) and its moderate interactions with DTS support. [ABSTRACT FROM AUTHOR]

An environmentally benign, simple and mild approach has been adopted for the biogenic fabrication of Ag, Cu and Au MNPs (Metal nanoparticles) using Syzygium cumini leaf extract, at room temperature. This is an aqueous phase synthesis and excludes the use of toxic organic solvents. The TEM images revealed that the as-prepared MNPs possess spherical morphology with an average diameter of 6 nm. Application of these MNPs as nanocatalyst was investigated in decomposition of two organic dyes CR (Congo red) and RB (Rose bengal) in the presence of sodium borohydride (NaBH4), which is otherwise extremely slow. The rate constants of decomposition reactions were determined and found to follow the order—kAg > kCu > > kAu > kuncat, for both the dyes. Difference in the catalytic activity arise from the difference in their work function values. High catalytic activity of Ag NPs, as compared to Cu and Au, is attributed to its least work function value. [ABSTRACT FROM AUTHOR]

Discharge of unprocessed coloured waste water from industries gives rise to water contamination. In the current work, we propose the application of CuO nanoparticles supported on cellulose kitchen wipe sponge as a heterogeneous catalyst for the reductive decolourization of various toxic cationic and anionic dye molecules. The catalytic activity of the CuO nanoparticles under normal light for reduction has been examined in which sunlight irradiation is not necessitated. The CuO nanoparticles were synthesized by a simple wet chemical method and characterized using High Resolution Transmission Electron Microscope (HRTEM), SEM, EDX, XRD, XPS and TGA analyses. In the presence of CuO@CS catalyst and sodium borohydride, decolourization reaction of dyes such as acid red, acid green, methylene blue, rhodamine B and solochrome black-T was carried out. The catalytic reduction behaves as a pseudo-first-order reaction and is found to be superior in comparison with other reported catalysts in terms of reaction velocity. The reduction reaction can be further accelerated by increasing the reaction temperature. The developed catalyst drives the reduction faster on exposing the reaction mixture to sunlight confirming the usage of the catalyst at normal light and sunlight conditions. The catalyst retains 100% efficiency even after 5 cycles and remains suitable even for further use. Thus, a low-cost heterogeneous catalyst has been successfully developed and employed to decolourize various dye molecules in short duration with good recyclability and therefore can be used as the potential candidate in environmental remediation. [ABSTRACT FROM AUTHOR]

In this work, a photocatalyst Ag/AgCl/ZIF-8/TiO2 was facilely assembled on the surface of cotton fabrics via a simple method to fabricate a visible-light photocatalyst composite. The resultant cotton fabric was comprehensively characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and UV–vis diffuse reflection spectroscopy. The results showed that the Ag/AgCl/ZIF-8/TiO2 aggregations have successfully assembled on the surface of cotton fabric. Subsequently, Ag/AgCl/ZIF-8/TiO2 coated cotton fabric was employed as a visible-light photocatalytic material for degradation of organic dyes using methylene blue (MB) as a model. Owing to the synergistic effect of the Ag/AgCl/ZIF-8/TiO2 composite, the functional cotton fabric presented highly efficient photocatalytic degradation performance towards MB, the degradation of MB by Ag/AgCl/ZIF-8/TiO2 coated cotton fabric can reach to 98.5% within 105 min under visible light irradiation. Moreover, the first-order kinetic constant of photocatalytic degradation was 0.0332 min−1. Additionally, Ag/AgCl/ZIF-8/TiO2 coated cotton fabric exhibited acceptable cycle stability. The photocatalytic degradation capacity of MB still can maintain approximately 85% after three cycles. Therefore, Ag/AgCl/ZIF-8/TiO2 coated cotton fabric can be viewed as a good material for dye wastewater treatment due to its good photocatalytic activity and acceptable cycle ability. [ABSTRACT FROM AUTHOR]

In this study, TiO2 nanotubes (TNTs) and AgCl-modified TNTs nanocomposites with multiple crystal phases were synthesized through a hydrothermal method without calcination. The resultant samples had a large Brunauer-Emmett-Teller surface area. Additionally, the Ag modification process reduced the recombination rate of electron-hole pairs in the synthesized sample and possessed more oxygen vacancy sites. The surface area of the AgCl-modified TNTs was smaller than that of non-modified TNTs sample; however, the nanocomposites exhibited outstanding photocatalytic performance and adsorption properties. AgCl compounds present on the TNTs surface effectively interacted with Hg0, improving the dye photodegradation efficiency. The Hg0 removal efficiencies of the TNTs and AgCl-modified TNTs samples were about 63% and 86%, respectively. The crystal violet (CV) and malachite green (MG) removal efficiencies of the AgCl-modified TNTs sample were around 57% and 72%, respectively. Both dyes photodecomposition efficiencies for AgCl-modified TNTs sample are higher than those of TNTs sample. The oxygen vacancy on the AgCl-modified TNTs surface was determined to be advantageous for OH− and arsenate adsorption through ligand exchange. The maximum adsorption quantity of As5+ calculated by Langmuir equation was 15.38 mg g−1 (TNTs) and 21.10 mg g−1 (AgCl-modified TNTs). [ABSTRACT FROM AUTHOR]

In this study, a novel synthesis of Ag2S nanoparticles on the cellulose/Fe3O4 nanocomposite template through a green and economical method was proposed. The Ag2S nanoparticles grew on the environmentally benign cellulose/Fe3O4 nanocomposite via green pathway using the leaf and seed extract of Pistacia atlantica plants as reducing and stabilizing agent. The leaf extract showed the best results for developing of Ag2S nanoparticles on the nanocomposite surface. The synthesized magnetic nanocatalyst was characterized by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray powder diffraction and Fourier transform infrared spectroscopy. This catalyst showed high reductive degradation performance for the removal of methyl blue, methyl red and methyl orange from wastewater. The magnetic nanocatalyst could be separated easily after the process with the assistance of an external magnet. [ABSTRACT FROM AUTHOR]

Series of metal-free dyes (OMS4-7) featuring a dibenzofulvene connected with thienyl or furanyl as conjugation bridge, T-shaped diarylamines (diphenylamine or phenyl-1-naphthylamine) as donors and different numbers of cyanoacrylic acid as anchors have been synthesized and applied into dye-sensitized solar cells (DSSCs). The efects of different donors, conjuation segments and number of anchors on optical and photovoltaic properties were investigated through photophysics, electrochemical and photovoltaic measurements. Of the DSSCs, the structure contains mono anchor with thienyl dibenzofulvene linked to diphenylamine, i.e. OMS4-based device exhibited the highest power conversion efficiency (PCE) of 2.42%, a value of Jsc of 6.01 mA cm−2, a Voc of 0.63 V, and a fill factor of 0.63 under 10 mM CDA co-adsorbent and AM 1.5 irradiation. The corresponding device was also conducted with respect to different light intensity such as D65, CWF and TL84. As a result, the cell performance based on TL84 with 2500 lx exhibited the best PCE of 8.78%. [ABSTRACT FROM AUTHOR]

This paper reports the facile hydrothermal approach to synthesize porous CuO nanosheets. Their crystalline phase, metallic vibrations, topography, morphology, pore size distribution and magnetic behavior has been studied in detail. Magnetic properties of nanosheets were studied at 300 K using vibrating sample magnetometer which indicates the superparamagnetic behavior with saturation magnetization of 2.46 emu g−1 for as prepared 2D nanostructures. The electrochemical spectroscopy of these sheets reveals that as prepared sheets have a specific capacitance of 1057 F g−1 at a current density of 2 A g−1 which is retained up to 93% even after 4000 cycles. Furthermore, photocatalytic activity along with electrochemical properties of the as-obtained nanostructures were studied for various organic dyes. The high value of saturation magnetization, high specific capacitance and better dye degradation properties of the developed CuO nanosheets make the developed materials good for application in energy storage devices, astonishing electrode material and photocatalyst for degradation of organic dyes in visible light. [ABSTRACT FROM AUTHOR]

In this work, Ag2O/B2O3/TiO2 ternary nanocomposite was synthesized by a combination of green and precipitation method involving mixing of different concentrations of silver nitrate, boric acid, and titanium (IV) isopropoxide precursor with Plumeria acuminate leaf extract. The extract was obtained by boiling the mixture of distilled water and the powdered leaves in a beaker for few minutes followed by filtration. The microstructure, morphology, chemical composition, surface area, phase structure, and optical properties of the various prepared nanomaterials were determined by HRTEM, HRSEM, UV-Vis/DRS, BET, XRD, and XPS. The photocatalytic potential of TiO2 nanoparticles and Ag2O/B2O3/TiO2 nanocomposites to degrade local dyeing wastewater under artificial and natural sunlight irradiation was investigated. The extent of degradation of the organic pollutants was measured using chemical oxygen demand (COD) and total organic carbon (TOC) as indicator parameters. The XRD pattern of Ag2O/B2O3/TiO2 nanocomposites revealed that the formation of pure anatase TiO2 phase and the addition of both silver and boron precursors did not influenced the phase structure of the nanocomposites. The oxidation states of +1 and +3 for both Ag and B on the surface of Ag2O/B2O3/TiO2 nanocomposites were confirmed by XPS. Optical characterization of the sample revealed reduction of band gap energy from 2.6 to 2.0 eV for TiO2 and Ag2O/B2O3/TiO2, respectively. The Ag2O/B2O3/TiO2 nanocomposites demonstrated excellent photocatalytic activity under natural sunlight and artificial light than mono and binary oxide systems with TOC and COD degradation efficiencies of 86.11% and 75.69%, respectively. The kinetics of degradation of organic dyes in the wastewater followed the order of Langmuir–Hinshelwood pseudo-first-order > Freundlich > Zero > Parabolic diffusion model. The coupling effect of Ag2O and B2O3 onto TiO2 framework was responsible for the enhanced photochemical stability of the nanocomposites even after five repeated cycles. [ABSTRACT FROM AUTHOR]

Two novel dyes 3a and 3b named triphenylamine groups containing donor–acceptor structural units have been explored to be used in dye sensitized solar cells as organic sensitizers. The absorption bands of the dyes were extended up to ~ 550 nm with visible absorption maxima at 408–430 nm and optical band gaps of 2.44–2.47 eV. Compared to the methoxyphenyl-substituted dye, the introduction of triisopropylphenyl group instead of that increased fluorescence quantum yields and exhibited red-shift emission in chloroform. We have investigated the photovoltaic properties of DSSCs based on these metal free organic dyes. It has been found that the power conversion efficiency of DSSCs sensitized with methoxyphenyl based triphenylamine dye is higher than that for sensitized with triisopropylphenyl derivative. [ABSTRACT FROM AUTHOR]

In this work, 11 newly designed organic dyes with D-π-A-A structure based on a 3D triphenylamine derivative known as indacenodithiophene-triphenylamine (IDTTPA) as a core, benzoic acid as the anchoring group and linked by various spacer fragments containing electron-acceptor character have been theoretically studied using density functional theory (DFT) and time-dependent DFT (TD-DFT) for dye-sensitized solar cells (DSSCs). This three-dimensional structure is very important in retarding dyes aggregation and charge recombination, besides enhancing the power conversion efficiency (PCE) of DSSC, we have further employed various auxiliary acceptors to facilitate the electron transfer from the donor to the acceptor. Seven different functionals containing 0–100% Hartree–Fock (HF) exchange and three solvent models have been tested in this study. Comparison between computational and experimental absorption of D1 indicates that the maximum wavelength was accurately reproduced by a BHandHLYP functional and solvation model based on density (SMD) solvent model. The molecular structures, energy levels, absorption spectra, light harvesting efficiency (LHE) and driving force of injection (ΔGinject) are calculated. To sum up, these results indicate that the addition of an auxiliary acceptor into the core of the dye molecule has a significant effect on several properties including the planarity showed in this investigation, the decreasing in gap energy of 1.15 eV, and a bathochromic shift of 180 nm. It was found that the dye D4 with auxiliary acceptor 1,2,5-thiadiazolo[3,4-d]pyridazine shows a strong tendency to planarization, and possess the lowest values for bandgap of and open-circuit photovoltage 1.544 eV and 0.733 eV, respectively, the highest Δ G inject value (− 1.23 eV) and a maximum wavelength absorption of 608.85 nm, which makes this dye exhibits positive results and can be used as a promising candidate for DSSCs. [ABSTRACT FROM AUTHOR]

The Zn(II) metal Schiff-base complex was synthesized by the cost-effective chemical precipitation technique. It was determined that Zn(II) metal Schiff-base complex was polycrystalline and nano-sized (21.43 nm) by XRD analysis. This metal complex with polycrystalline structure was used as a sensitizer in organic dye sensitized solar cell. As a result of the analysis, the power conversion efficiency value of this metal complex was found to be 0.73. Although the solar cell performance of Zn(II) metal Schiff-base complex, which is synthesized by simple and inexpensive chemical methods, is low, it has been found to be of considerable importance when compared to the efficiency of expensive organic dyes. [ABSTRACT FROM AUTHOR]

This paper describes the removal of methylene blue (MB) dye using [Fe(II)]-based gas diffusion electrodes (GDEs). GDEs were developed by rolling carbon black and polytetrafluoroethylene as a conductive layer for efficient oxygen reduction reaction, with an [Fe(II)] ink layer ( 5 mg cm - 2 loading) to conduct Fenton chemistry. The GDEs demonstrated the ability to remove the colour and mineralize MB dye in an undivided, three-electrode cell. Colour removal achieved 99% in a 150 cm 3 solution containing 100 ppm of MB dye at constant potential of - 1.0 V vs. Hg/HgSO 4 in 240 min. The kinetics of the MB decolouration showed pseudo-first-order batch kinetics. The results demonstrated that a GDE containing immobilized Fe(II) ions appears to be a viable option for the environmental remediation of organic dyes in wastewater by an anodic Fenton oxidation. [ABSTRACT FROM AUTHOR]

Zeolites HY and 13X were modified by magnetic nanoparticles and were denoted as MHY and M13X, respectively. MHY and M13X were characterized by vibrating-sample magnetometry, X-ray diffraction analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential, and Brunauer–Emmett–Teller surface area analysis. MHY and M13X were used as adsorbents for the removal of methylene blue (MB) from aqueous solution. Response surface methodology combined with central composite design was used for statistical modelling aimed at the removal process optimization. The effects of the independent variables on the removal process were evaluated, focusing primarily on the solution pH (which was varied in the 3–9 range), temperature (25–55 ∘ C ), the adsorbent dose (300–1200 mg/L), and the initial dye concentration (10–40 mg/L). The solution pH and the absorbent dose had the greatest effects on the MB removal rate. The maximum MB removal of 99.85% was achieved using MHY at the optimum conditions ( pH = 9 , temperature = 53.91 ∘ C , initial MB dye concentration = 10.23 mg/L , and adsorbent dose = 1186 mg/L ), while 95.9% was achieved using M13X at the optimum conditions ( pH = 8.93 , temperature = 53.39 ∘ C , initial MB concentration = 10.05 mg/L , and adsorbent dose = 1198 mg/L ). The equilibrium data of MB adsorption onto M13X and MHY were studied using the linear and nonlinear form of the Freundlich and Langmuir models, with Langmuir providing a better fit. The obtained kinetic statistics indicated that the adsorption kinetics are more accurately represented by a pseudo-second-order model for both adsorbents. Finally, the calculated thermodynamic parameters indicated that the adsorption is spontaneous and endothermic. [ABSTRACT FROM AUTHOR]

In this work, the fabrication of MoS2-Polyaniline (PANI) nanocomposites, by in situ polymerization, has been described and its application as a photocatalyst for the degradation of organic pollutants such as methylene blue (MB) and 4-chlorophenol (4-CP), has been reported. The disadvantages of MoS2 such as poor electronic conductivity and agglomeration between the nanosheets, was overcome by intercalating 2D MoS2 layers with 1D conducting polymer, Polyaniline (PANI). The composite material was characterised by SEM, TEM, BET, XRD, FTIR, UV–Vis spectroscopy and XPS, indicating proper intercalation between MoS2 nanosheets and PANI. Consequently, the synthesized composites were used for the degradation of MB and 4-CP, followed by kinetic investigations to determine the rate kinetics. The photoactivity of the nanocomposite is explained by the transfer of photogenerated electrons from PANI to the CB of MoS2, thus preventing the direct recombination of electrons and holes. Hence, a positive synergistic effect between MoS2 and PANI resulted in efficient photocatalytic degradation of organic dyes like MB. [ABSTRACT FROM AUTHOR]

Composite photocatalysts composed of semiconductor and magnetic matters are of great concern due to their excellent catalytic and recyclable performances. In this work, hydrothermal synthesis technique was employed to prepare magnetic Fe3O4/SnO2 nanocomposites (FS1, FS2, and FS3) of different molar ratios. The nanocomposites material was characterized by powder X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), energy-dispersive X-ray spectroscopy (EDS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS), Vibrating sample magnetometer (VSM) analysis. The SnO2 optical absorption was extended into visible region after coupling with Fe3O4. The magnetic features of Fe3O4/SnO2 nanocomposites offer simply separable method for reusability of the material in photocatalytic application. The catalytic activity of as prepared magnetically separable nanocomposites was inspected based on photodegradation of crystal violet as model organic pollutant. The extent of variation of field-dependent photo and dark current of the samples were determined from photoconductivity studies. The photoconductivity studies revealed the ohmic nature of the samples with a linear increase in both dark and photocurrent with a corresponding increase with increase in the applied field. The nanocomposite FS1 depicted good photocatalytic activity due to enlarged photoresponsive range and increase in charge separation rate. From the results, we suggest an attractive physical property and an efficient and a recyclable nanocomposite catalyst active under UV light irradiation for use in wastewater treatment to control water pollution. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of pollutant using TiO2@SiO2 nanocomposites (NCs) is a well route for the treatment of the organic waste in aquatic life. The recent work focuses on the removal of many organic dyes like methylene blue, eosin and safranin and study the pollutant degradation of them using the activity and high efficiency of titania as well as nanostructured titania@silica. The impregnation of silica with anatase-type TiO2 was carried out through a sol–gel way. The obtained powders were checked and characterized using N2 adsorption–desorption complete isotherm at low temperature, BET, FESEM, XRD, PL, UV–Vis spectroscopy, diffuse reflectance spectra and the photocatalytic activity to attain the homogeneity distribution of the nanostructure particles inside the matrix. TiO2@SiO2 material displayed good photocatalytic properties compared to a pure titania. Different parameters as the type of the photocatalyst, pH of solution, amount of the photocatalyst and adsorption were studied. In addition, reusability for dye removal under consecutive cycles was also investigated. Photocatalytic activity and the excellent properties of the TiO2@SiO2 NCs displayed that these materials can consider being good candidate considered in water treatment applications. [ABSTRACT FROM AUTHOR]

The toxicity of the organic dyes presents in the environment due to polluted discharge from industries is a real dilemma in the world. Here, the problem was addressed with the synthesis of new quaternary mineral cupric antimony oxychloride (CAO) during the study of Cu–Sb–O–Cl system in absence of solvents. The morphological analysis showed that synthesized matrix is rough and uneven with round and cylindrical shapes. The composition of nanomaterial verified the elemental composition as Cu, Sb and Cl. The XRD analysis revealed that synthesized product CAO is crystalline in nature where crystallite size was estimated in the range of 2–8 nm. The bond vibrations were studied through Fourier transforms infrared spectroscopy to confirm the symmetric and asymmetric vibrations in the matrix. The material parameters (grain size, dislocation line density, stresses and miller indices) of the synthesized material CAO were calculated using powder X-ray diffraction analysis. Thermogravimetric analysis was performed to study the decomposition behaviour and stability of the CAO. The copper ternary compound was used to mitigate the effect of organic dyes like Sunset yellow (26%), Methylene blue (23%), Brilliant green (20%), Methyl orange (14%) in the dyes polluted wastewater. [ABSTRACT FROM AUTHOR]

One of the appealing usages of metal–organic frameworks is their application in manufacturing of metal oxide and metal oxide nanocomposites. In the present study, we used zeolitic imidazolate framework (ZIF-8) as precursor to prepare a new Ag/C/ZnO catalyst. The as-prepared samples were characterized using X-ray diffraction, Fourier-transform infrared, scanning electron microscopy and transmission electron microscopy analysis. Improved catalytic performance of as-prepared Ag/C/ZnO was confirmed by reduction of organic pollutants including p-nitrophenol, methylene blue and rhodamine-B in the presence of NaBH4 in aqueous media. The synergistic effect between Ag and ZnO was proposed as the main reason for the remarkably enhanced catalytic activity of Ag/C/ZnO. [ABSTRACT FROM AUTHOR]

In this work, a new type of advanced 3D mesoporous carbon nanocomposites derived from Zn dust/PET bottle mixed waste with a high surface area is created. Interestingly, simultaneous transformation of Zn metal into ZnO nanoparticles and PET bottle waste to porous carbon materials occurred upon thermal treatment at 700 °C. The effect of the amount of Zn metal on the prepared materials has been studied. The carbon material-based waste presented very large surface area (up to 684.5 m2/g) with pore size distribution (18.47–16.88 nm). The SEM and TEM analysis revealed that the produced carbon materials have 3D porous dense layers with a gradient pore structure. The created waste-based nanocomposite exhibited an enhanced photocatalytic performance for the degradation of organic dyes (methylene blue and malachite green). It is believed that the presented work not only provides a sustainable approach to the creation of new nanocomposites of ZnO-mesoporous carbon materials for the application in photocatalysis but also introduces a new way of upcycling of mixed waste materials. [ABSTRACT FROM AUTHOR]

Abstract: Photocatalysis using semiconductors has emerged as a promising wastewater treatment process to overcome the major challenges faced by conventional technologies. The advantages of ZnO nanomaterials over other semiconductors, and their structure-dependent properties, make them important building blocks in nanotechnology as multifunctional materials. Moreover, it has been confirmed that ZnO nanomaterials can exhibit high performance in photodegradation of organic dyes for treatment of industrial effluent. The wurtzite structure of ZnO contains polar and nonpolar planes; the low surface energy and thermodynamic stability of the nonpolar planes enable formation of one-dimensional (1D) ZnO structures, which are desirable compared with zero-dimensional (0D) and two-dimensional (2D) nanoarchitectures. Also, relative to other forms, the superiority of 1D ZnO nanostructures in dye photodegradation makes them promising as a future research direction and for commercial use. Therefore, understanding the design and synthesis of 1D ZnO nanomaterials is of critical importance for the development of novel and high-performance photocatalysts. Rational design of 1D ZnO nanophotocatalysts is thus required to enhance their photodegradation activity via efficient separation of charge carriers, increased surface-to-volume ratio, enhanced light absorption capacity, and improved stability/reusability. We briefly describe herein the most widely applied synthesis methods, including vapor-phase and solution-based strategies, to understand different methods for tailoring 1D ZnO nanophotocatalysts. Moreover, to elucidate the effect of their physical/chemical properties on the photodegradation efficiency, all the modification methods are categorized into four different approaches, viz. (1) morphology control, (2) induction of defects, (3) modulation by doping, and (4) formation of hybrids and heterojunctions. An overview of all aspects of charge generation, separation, and transfer during dye photodegradation by engineered 1D ZnO nanomaterials is also provided.Graphical abstract: [ABSTRACT FROM AUTHOR]

This work reports the improvement in the photon absorption and degradation of acetaminophen (ACF) and diclofenac (DFC) by photosensitizing TiO2 with two types of dyes Eosin Y (Ey) and Rhodamine B (RhB). Experimental tests were carried out in a solar simulator for three hours for different systems and both pollutants. The influences of the TiO2 concentration (100, 200 and 800 mg L−1) and the catalyst–dye ratio (2%, 5% and 10%) were investigated. The degradation of the compounds was higher in the presence of TiO2-Ey compared to the TiO2-RhB and TiO2 for both pharmaceutical compounds, which was attributed to the anionic nature of Ey. DFC total degradation was achieved using 100 mg L−1 of catalyst loading and 10% of catalyst–dye ratio and the highest ACF degradation (71%) was obtained at 800 mg L−1 of catalyst loading and 5% of catalyst–dye ratio. The photon absorption was studied for both dyes using the six-flux absorption scattering model (SFM) for estimating the LVRPA (local volumetric rate of photon absorption). This was done by modifying the apparent optical thickness equation. It was found that the presence of dye in the photocatalytic systems considerably increases the LVRPA. The rate coefficients for the degradation of pharmaceutical compounds in the presence of the organic dyes were also obtained. [ABSTRACT FROM AUTHOR]

In this study, we synthesized novel visible light photocatalyst MIL-88A/BiOI using depositing BiOI particles on the surface of a metal-organic framework (MIL-88A). Photocatalytic application of binary composite MIL-88A/BiOI was obtained by discoloration of Methylene Blue (MB) and Acid Blue 92 (AB92) in aqueous solution under visible light source. The photodegradation experiments for treating organic dyes show that the MIL-88A/BiOI heterojunction structure possess a higher rate for decomposition of dyes due to the decreased aggregation of the BiOI nanoparticles, effective charge carrier separation and the synergistic effect between MIL-88A and BiOI samples as a heterojunction. Also, the MIL-88A/BiOI structure shows better photocatalytic degradation performance for anionic dyes (AB92) than for a cationic dye (MB). It was further found that •OH and •O2− radicals were the most important species responsible for the photodegradation test. [ABSTRACT FROM AUTHOR]

A laser-based method was developed for the synthesis and simultaneous deposition of multicomponent hybrid thin layers consisting of nanoentities, graphene oxide (GO) platelets, transition metal oxide nanoparticles, urea, and graphitic carbon nitride (g-C3N4) for environmental applications. The photocatalytic properties of the layers were tested through the degradation of methyl orange organic dye probing molecule. It was further demonstrated that the synthesized hybrid compounds are suitable for the photodegradation of chloramphenicol, a widely used broad-spectrum antibiotic, active against Gram-positive and Gram-negative bacteria. However, released in aquatic media represents a serious environmental hazard, especially owing to the formation of antibiotic-resistant bacteria. The obtained results revealed that organic, urea molecules can become an alternative to noble metals co-catalysts, promoting the separation and transfer of photoinduced charge carriers in catalytic composite systems. Laser radiation induces the reduction of GO platelets and the formation of graphene-like material. During the same synthesis process, g-C3N4 was produced, by laser pyrolysis of urea molecules, without any additional heat treatment. The layers exhibit high photocatalytic activity, being a promising material for photodegradation of organic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

[6,6]-Phenyl-C61-butyric acid methyl esters (PCBM) have emerged in recent years as important building blocks for photovoltaic devices. However, the potential of PCBM itself as a photocatalyst has not been reviewed. Here, we demonstrate PCBM nanoparticles (NPs) fabricated by the reprecipitation method as suitable photocatalysts for an effective visible-light-driven photocatalytic degradation for organic dyes. An enhanced catalytic performance of PCBM can be achieved by a simple annealing process. The present PCBM NPs outperform the state-of-the-art P25 TiO2 and therefore highlights its potential as promising small molecule organic semiconductor photocatalysts with high photocatalytic activity and good long-term stability. [ABSTRACT FROM AUTHOR]

A novel triple-layered transparent conductive film TiO2/CdS/Pd heterostructure was deposited via galvanic deposition on glass substrate at room temperature. Photocatalysts with wide optical absorption regions and efficient charge carrier transport capacity are highly efficient for photocatalytic activity. Oxides of high band gap can be coupled with chalcogenide semiconductors for the efficient photocatalytic degradation of metal and dyes. So, in our work synthesis of TiO2/CdS heterostructure increases the absorption capacity of TiO2. Further, deposition of a noble metal like palladium over this heterostructure increases the charge separation, which in turn diminishes electron-hole pair recombination. [ABSTRACT FROM AUTHOR]

Carbon-containing materials were produced from a mixture of bentonite clay and Crystal Violet dye adsorbed on the clay. X-ray diffraction analysis and IR spectroscopy were used to examine the thermal and structural transformations occurring in a thermal treatment of a mixture of the clay and the adsorbed dye in the atmosphere of water steam, and the optimal carbonization conditions were determined. It was shown that the materials possess a high adsorption capacity for basic organic dyes. [ABSTRACT FROM AUTHOR]

Twelve novel dye molecules developed from D-π-A-based triphenylamine (TPA) dyes were studied to evaluate their suitability for dye-sensitized solar cells (DSSC), using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The effects of flavone and isoflavone on triphenylamine-based dyes were studied. B3LYP and CAM-B3LYP density functionals combined with 6-311G(d,p) basis set were chosen for optimization and TDDFT respectively. Optimization geometry, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy level, and absorption spectrum were calculated. The electron injection force and light-harvesting efficiency were calculated. We have found HOMO, LUMO energy levels, and electronic absorption spectrum suitable for DSSC application. Based on theoretical calculations, the usefulness of flavones and isoflavones-added triphenylamine dye molecules for DSSC application is examined. [ABSTRACT FROM AUTHOR]

Metal oxides particularly for zinc oxide (ZnO) particles are well-known to exhibit photocatalytic activities. However, the specific morphology and superstructure of nanomaterials can significantly influence this capacity. Here, it is shown that different crystalline structures of ZnO particles are provided by a facile one-step wet-chemical route. One possible formation mechanism has been elucidated for the fabrication of distinct metal oxide samples including flower-like, sphere-like and leaf-like ZnO under different synthesis conditions. It is also found that the photodegradative performance for organic dye is directly correlated to the morphological properties of these as-prepared catalysts; the higher the active surface area the better is the photocatalytic efficiency. Not only can ZnO structure with abundant mesoporous aggregated by leaf-shape arrays lead to more methylene blue immobilization, but also generate more photoinduced electrons and holes on the crystalline surface. The results also illustrate that the morphology-dependent catalytic performance can be further improved combining with other optimized photodegradative conditions (e.g. pH, illumination mode). The present study can lead to new metal oxide with high-performance important for photocatalytic and environmental applications. [ABSTRACT FROM AUTHOR]

Environmental and health concerns arising from the toxicity of organic dye effluents is still the issue of the twenty-first century. In that regard, this study presents iron sulfide (FeS2) for its use in environmental remediation application. Amorphous phase FeS2 nanowires were synthesized by PVP-assisted solvothermal reaction and were characterized using XRD, XPS, BET, FE-SEM, and EDS techniques. The amorphous phase FeS2 is attractive from material synthesis point of view as its synthesis does not require delicate control over the process parameters, unlike the crystalline phase. The 1-D nanowire FeS2 had a high surface-to-volume ratio with negative zeta potential within a wide pH range. Having those surface and microstructural properties, these nanowires exhibited excellent adsorption property towards model organic dyes, Congo red (anionic), and methylene blue (cationic), with theoretical adsorption capacity of 118.86 and 48.82 mg g−1, respectively. Adsorption kinetics and isotherm models were implemented to study the adsorption processes at different adsorption conditions (pH, adsorbent loading, initial adsorbate concentration). The pH dependence of the adsorption and FT-IR analysis evidenced the prevalence of both physisorption and chemisorption during the adsorption of Congo red. Recyclability test proved the excellent performance of this amorphous FeS2 nanowire adsorbent for three consecutive cycles. Considering its ease of synthesis, excellent adsorption property, and cyclic performance, the as-prepared adsorbent could be a promising material for dye effluents treatment. [ABSTRACT FROM AUTHOR]

The organic/inorganic hybrid material of poly[2-(dimethyl amino)-ethyl methacrylate]/polyhedral oligomeric silsesquioxane (POSS-PDMAEMA) was synthesized via a thiol-Michael addition reaction. The structures of POSS-PDMAEMA and its self-assembly in aqueous solution were confirmed by 1H-NMR, TEM, DLS, UV-Vis and fluorescence spectrum. In aqueous solutions, POSS-PDMAEMA could self-assemble into micelles and its critical micelle concentration was 12.4 mg/L. POSS-PDMAEMA micelles can adsorb dyes efficiently, it could adsorb methyl red at a concentration of 10-100 mg/L and dithizone at a concentration of 20-100 mg/L, and could remove 98% methyl red and 90% dithizone within 30 s. Due to the good temperature and pH responsiveness, POSS-PDMAEMA micelles could release organic dye absorbed into the organic solution again when the solution was heated to 40 °C or pH value of the solution was adjusted to 4.0. It suggested that POSS-PDMAEMA can be utilized as an interesting "smart" materials for absorption of organic dyes. [ABSTRACT FROM AUTHOR]

The use of high-throughput multiplexed screening platforms has attracted significant interest in the field of on-site disease detection and diagnostics for their capability to simultaneously interrogate single-cell responses across different populations. However, many of the current approaches are limited by the spectral overlap between tracking materials (e.g., organic dyes) and commonly used fluorophores/biochemical stains, thus restraining their applications in multiplexed studies. This work demonstrates that the downconversion emission spectra offered by rare earth (RE)-doped β-hexagonal NaYF4 nanoparticles (NPs) can be exploited to address this spectral overlap issue. Compared to organic dyes and other tracking materials where the excitation and emission is separated by tens of nanometers, RE elements have a large gap between excitation and emission which results in their spectral independence from the organic dyes. As a proof of concept, two differently doped NaYF4 NPs (europium: Eu3+, and terbium: Tb3+) were employed on a fluorescent microscopy-based droplet microfluidic trapping array to test their feasibility as spectrally independent droplet trackers. The luminescence tracking properties of Eu3+-doped (red emission) and Tb3+-doped (green emission) NPs were successfully characterized by co-encapsulating with genetically modified cancer cell lines expressing green or red fluorescent proteins (GFP and RFP) in addition to a mixed population of live and dead cells stained with ethidium homodimer. Detailed quantification of the luminescent and fluorescent signals was performed to confirm no overlap between each of the NPs and between NPs and cells. Thus, the spectral independence of Eu3+-doped and Tb3+-doped NPs with each other and with common fluorophores highlights the potential application of this novel technique in multiplexed systems, where many such luminescent NPs (other doped and co-doped NPs) can be used to simultaneously track different input conditions on the same platform.ᅟ [ABSTRACT FROM AUTHOR]

We report the fabrication of solid-state dye-sensitized solar cells (ss-DSSCs), using a metal-free organic dye (D102) as a sensitizer. Mesoporous TiO2 acting as a photoanode, is prepared from TiO2 nanopaste followed by drafting light-absorbing dye molecules. Spiro-OMeTAD is used as a hole transport material (HTM), which has a potential role in the energy conversion process of solid-state dye-sensitized solar cells (ss-DSSCs). Here, TiO2 mesoporous films are used with three different thicknesses (∼ 1.5 μm, ∼ 1.7 μm and ∼ 2.0 μm) for the device fabrication. Various characterizations of optimum TiO2 porous film (with the thickness of ∼ 2.0 μm) are performed such as ultraviolet-visible (UV-Vis) transmission, x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and cross-section scanning electron microscopy (SEM). Transmittance analysis reveals that transparency of the TiO2 films ranges from 70% to 80%. The x-ray diffraction (XRD) pattern of TiO2 shows anatase as its major crystalline phase. The porous structure formation of the TiO2 film is confirmed by scanning electron microscopy (SEM) cross section analysis. Photovoltaic performance of the devices was examined in air. Higher power-conversion efficiency (PCE) of 3.5% is obtained with optimum device thickness (∼ 2.3 μm). The device stability test is performed under continuous illumination for 2 h, showing slightly good air and light stability. [ABSTRACT FROM AUTHOR]

Three novel dithieno[3,2-f:2′,3′-h]quinoxaline-based organic dyes (IQ-C, IQ-D and IQ-F) with three π-spacers were synthesized and developed for dye sensitized solar cells, where dithieno[3,2-f:2′,3′-h]quinoxaline was used as electron-withdrawing π-spacers, and 2,3-diphenylquinoxaline or dibenzo[a,c]phenazine as auxiliary electron-withdrawing π-spacers. The dye IQ-D with 2,3-diphenylquinoxaline as auxiliary electron-withdrawing π-spacer exhibited higher photocurrent (Jsc) and photovoltage (Voc) than that of the dye IQ-C with 2,3-bis(4-(octyloxy)phenyl)quinoxaline as the additional electron-withdrawing π-spacer, due to the larger adsorption amount of IQ-D. The dye IQ-F with a rigid conjugated dibenzo[a,c]phenazine as additional electron-withdrawing π-spacer showed the highest efficiency of 6.54% under AM 1.5 G irradiation. It was demonstrated that the π-spacers influence the photovoltaic performance of the dithieno[3,2-f:2′,3′-h]quinoxaline-based organic dyes significantly. The results indicated that the dyes with three π-spacers are promising candidates for efficient dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]

Co-sensitization of metal-free (Eosin and Coumarin) and metal-based (N3 and N719) organic dye combinations were employed with TiO2 nanoparticles based photoanodes for the fabrication of dye-sensitized solar cells. The charge injection and oxidized dye regeneration process in mono and co-sensitized system were explored from the constructed energy level diagram using cyclic voltammetry analysis. Electrochemical impedance measurements were performed to determine interfacial charge transfer kinetics such as chemical capacitance, recombination resistance and electron lifetime. Current density-Voltage (J-V) characteristics resulted an improved efficiencies in co-sensitized DSSCs due to increased short circuit current density (Jsc). The studies on polarization effect was also evaluated using conductivity plot of impedance spectroscopy. Here, we report for the first time, the internal polarization of dye-sensitizers contributes a small current in the total obtained current density (Jsc) of a device besides the conduction current which enhances the PCE. Especially, high polarization effect of coumarin dye by its resonance polar structure increasing the conductivity in intermediate frequency region of conductivity plot and thus the current density gets enhanced. Improved efficiency of ~ 5.4% was realized in pure metal-based dye co-sensitization by its optimized electron concentration in CB TiO2 to balance charge injection and recombination. [ABSTRACT FROM AUTHOR]

Biomass-derived adsorbents have been intensively studied due to their competence in reducing pollutants with conventional methods. Flowers are used as source in medicine, cosmetics and even as adsorbents for pollutant abatement. In this study, the microparticles from Chrysanthemum indicum were used as adsorbent for reducing the Congo red dye concentration from synthetic solution. Batch trials were evaluated to understand the influence of factors and optimization was carried out using central composite design. Maximum reduction (84.1%) achieved under the optimized settings of pH (1.0), adsorbent dose (300 ppm), stirring speed (150 rpm), and contact time (75 min) at initial dye concentration (150 ppm at 30 °C). Microparticle size ensured with surface morphology of the adsorbent using electron microscopy and functional groups was studied using infrared spectroscopy techniques, respectively. Regression coefficient (R2) value was obtained as 0.956 which indicates that the predicted values were in good agreement with their corresponding experimental values for the Congo red dye adsorption. Based on the investigation, it is inferred that the Chrysanthemum indicum flower has the potential for Congo red dye reduction from aqueous solution. [ABSTRACT FROM AUTHOR]