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Room temperature ligand-assisted reprecipitation syntheses of CsPbBr3 nanoparticles (NPs) under open air conditions and with non-polar solvents have recently emerged as viable strategies for large-scale production of highly emissive NPs.

Human immunodeficiency virus (HIV) can independently replicate in the central nervous system (CNS) causing neurocognitive impairment even in subjects with suppressed plasma viral load. The antiretroviral drug darunavir (DRV) has been approved for therapy of HIV-infected patients, but its efficacy in the treatment of HIV-associated neurological disorders (HAND) is limited due to the low penetration through the blood-brain barrier (BBB). Therefore, innovations in DRV formulations, based on its encapsulation in optically traceable nanoparticles (NPs), may improve its transport through the BBB, providing, at the same time, optical monitoring of drug delivery within the CNS. The aim of this study was to synthesize biodegradable polymeric NPs loaded with DRV and luminescent, nontoxic carbon dots (C-Dots) and investigate their ability to permeate through an artificial BBB and to inhibit

A facile in situ colloidal approach is reported to synthesize a novel hybrid nanocomposite formed of 3,4-dimethylbenzenethiol (DMBT)-capped Au NPs, decorating flakes of 1-pyrene-carboxylic acid (PCA) functionalized Reduced Graphene Oxide (RGO). In the nanocomposite, the Au NPs and RGO sheets are anchored by means of the aromatic PCA linker and the DMBT capping ligand, both ensuring electronic coupling due to particle/RGO and interparticle π-π interactions, respectively. The short aromatic thiol has been selected to i. yield additional binding sites for the NPs to the PCA-RGO surface, ii. potentially enhance electron conductivity and promote charge transfers, and iii. enable dispersibility in organic solvents. The role of the synthetic parameters on the resulting Au NPs morphology and on their organization onto the PCA-RGO sheets has been comprehensively investigated in order to elucidate the mechanism underlying the in situ NPs formation. Organic dispersions of the PCA-RGO flakes, densely and uniformly decorated with a multilayer network of DMBT-coated Au NPs, 2–3 nm in size, have been achieved, thus overcoming limitations previously reported for similar hybrid materials. The prepared nanostructures are attractive functional platforms for future FETs and (photo)electrochemical (bio)sensors, (photo)catalysis, photodetectors, memory devices and solar cells.

Carbon dots (CDs) have been progressively attracting interest as novel environmentally friendly and cost-effective luminescent nanoparticles, for implementation in light-emitting devices, solar cells, photocatalytic devices and biosensors. Here, starting from a cost-effective bottom-up synthetic approach, based on a suitable amphiphilic molecule as carbon precursor, namely cetylpyridinium chloride (CPC), green-emitting CDs have been prepared at room temperature, upon treatment of CPC with concentrated NaOH solutions. The investigated method allows the obtaining, in one-pot, of both water-dispersible (W-CDs) and oil-dispersible green-emitting CDs (O-CDs). The study provides original insights into the chemical reactions involved in the process of the carbonization of CPC, proposing a reliable mechanism for the formation of the O-CDs in an aqueous system. The ability to discriminate the contribution of different species, including molecular fluorophores, allows one to properly single out the O-CDs emission. In addition, a mild heating of the reaction mixture, at 70 &deg, C, has demonstrated the ability to dramatically decrease the very long reaction time (i.e. from tens of hours to days) at room temperature, allowing us to synthesize O-CDs in a few tens of minutes while preserving their morphological and optical properties.

Here, polyethylene glycol (PEG)-stabilized solid lipid nanoparticles (SLNs) containing Pt(IV) prodrugs derived from kiteplatin were designed and proposed as novel nanoformulations potentially useful for the treatment of glioblastoma multiforme. Four different Pt(IV) prodrugs were synthesized, starting from kiteplatin by the addition of two carboxylate ligands with different length of the alkyl chains and lipophilicity degree, and embedded in the core of PEG-stabilized SLNs composed of cetyl palmitate. The SLNs were extensively characterized by complementary optical and morphological techniques. The results proved the formation of SLNs characterized by average size under 100 nm and dependence of drug encapsulation efficiency on the lipophilicity degree of the tested Pt(IV) prodrugs. A monolayer of immortalized human cerebral microvascular endothelial cells (hCMEC/D3) was used as in vitro model of blood–brain barrier (BBB) to evaluate the ability of the SLNs to penetrate the BBB. For this purpose, optical traceable SLNs were achieved by co-incorporation of Pt(IV) prodrugs and luminescent carbon dots (C-Dots) in the SLNs. Finally, an in vitro study was performed by using a human glioblastoma cell line (U87), to investigate on the antitumor efficiency of the SLNs and on their improved ability to be cell internalized respect to the free Pt(IV) prodrugs.

This study presents the use of biodegradable poly (D,L-lactide-co-glycolide) (PLGA)-based NPs as nanovectors for the delivery of biocompatible luminescent Carbon Dots (C-Dots) and the antiretroviral drug Danuvir (DRV).

Colloidal semiconductor quatum dots (QDs) are promosing material for the fabrication of optoelectronic photonic and sensing application. This study presents the fabrication and characterization of naostructures composed of a low number of quatum dots.

Quantum dots (QDs) have extraordinary strong light absorption and size tunable bandgap. However, QD films are typically limited to ~200-300 nm due to their poor charge mobility. This severely limits the quantum efficiency of QD devices for λ

Currently, intensive research efforts focus on the fabrication of meso-structures of assembled colloidal quantum dots (QDs) with original optical and electronic properties. Such collective features originate from the QDs coupling, depending on the number of connected units and their distance. However, the development of general methodologies to assemble colloidal QD with precise stoichiometry and particle-particle spacing remains a key challenge. Here, we demonstrate that dimers of CdSe QDs, stable in solution, can be obtained by engineering QD surface chemistry, reducing the surface steric hindrance and favoring the link between two QDs. The connection is made by using alkyl dithiols as bifunctional linkers and different chain lengths are used to tune the interparticle distance from few nm down to 0.5 nm. The spectroscopic investigation highlights that coupling phenomena between the QDs in dimers are strongly dependent on the interparticle distance and QD size, ultimately affecting the exciton dissociation efficiency.

An investigation of the thermal, electrical and dielectric properties of original nanocomposite materials based on the incorporation of carbon dots, synthesized in organic solvents, in a poly(methyl methacrylate) (PMMA) is presented. Thermal analysis was performed using differential scanning calorimetry. Electrical and dielectric measurements were carried out in the frequency range from 100 Hz to 1 MHz and at temperatures between 200 and 400 K. The data were analyzed using two formalisms: (i) AC conductivity that has been found to follow the Jonscher’s power law with double exponents, and (ii) electric modulus that permits to identify two dielectric relaxation processes. The first one, appearing at low-frequency, was attributed to the conduction effect which is consistent with the Havriliak-Negami model, and the second one, appearing at high-frequency was associated with the interfacial polarization effect. Furthermore, the analysis of the temperature dependence of AC conductivity using the Arrhenius representation indicated the existence of two mechanisms basically governing the conductivity.

Efficient FRET systems are developed combining colloidal CdSe quantum dots (QDs) donors and BODIPY acceptors. To promote effective energy transfer in FRET architectures, the distance between the organic fluorophore and the QDs needs to be optimized by a careful system engineering. In this context, BODIPY dyes bearing amino-terminated functionalities are used in virtue of the high affinity of amine groups in coordinating the QD surface. A preliminary QD surface treatment with a short amine ligand is performed to favor the interaction with the organic fluorophores in solution. The successful coordination of the dye to the QD surface, accomplishing a short donor-acceptor distance, provides effective energy transfer already in solution, with efficiency of 76 %. The efficiency further increases in the solid state where the QDs and the dye are deposited as single coordinated units from solution, with a distance between the fluorophores down to 2.2 nm, demonstrating the effectiveness of the coupling strategy.

The design of large-scale colloidal quantum dots (QDs) assemblies and the investigation of their interaction with their close environment are of great interest for improving QD-based optoelectronic devices' performances. Understanding the interaction mechanisms taking place when only a few QDs are assembled at a short interparticle distance is relevant to better promote the charge or energy transfer processes. Here, small hetero-assemblies formed of a few CdSe QDs of two different sizes, connected by alkyl dithiols, are fabricated in solution. The interparticle distance is tuned by varying the linear alkyl chain length of the bifunctional spacer from nanometer to sub-nanometer range. The crystallographic analysis highlights that the nearest surfaces involved in the linkage between the QDs are the (101) faces. The thorough spectroscopic investigation enables a sound rationalization of the coupling mechanism between the interacting nanoparticles, ranging from charge transfer/wavefunction delocalization to energy transfer, depending on their separation distance., In press in Materials Research Bulletin. Available online 1 October 2021, 111578

The optical and the dielectric properties of an original nanocomposite based on the incorporation of carbon dots (C-dots) in poly(methyl methacrylate) (PMMA) at several filler loading were studied. The optical characterization demonstrated the preservation of the excitation dependent intense emission of the C-dots in the polymer, ascribed to the presence of organic fluorophores formed during the nanoparticle synthesis. The composite PMMA/C-dots dielectric properties were investigated in the frequency range from 40 Hz to 1 MHz and over the temperature range from 200 to 400 K. The dielectric response was obtained using the complex permittivity or the modulus formalisms, depending on the concentration of filler in the polymer matrix. A relaxation phenomenon was induced by the incorporation of the C-dots in the PMMA matrix. In addition, both the real and imaginary parts of the dielectric permittivity and electric modulus changed with the volume fraction of the C-dots, suggesting that the presence of the fillers greatly affect the dielectric properties of the polymer matrix because of polarization phenomenon induced by the nanoparticles. (C) 2018 Society of Plastics Engineers

Titanium and its alloys are widely employed materials for implants in orthopedic or dental surgery due to their mechanical properties, resistance to corrosion and osseointegration capability. However adverse reactions at the tissue/implant interface may occur, which limit the success of the osseointegration process. Therefore, different strategies have to be used to overcome these drawbacks. In this work, we developed two different liposome-based coatings on titanium surfaces as drug or bioactive molecule deposits for dental/orthopedic implant applications. The first one is a supported vesicular layer (SVL), obtained by liposome adhesion on passivated Ti surface, the second one is a covalently bonded vesicular layer (CBVL) grafted on properly functionalized Ti. Photoluminescence spectroscopy and atomic force microscopy investigations demonstrated the effective anchoring of intact liposomes in both systems. Cytotoxicity assays, performed after 48h, showed a MG63 cell viability higher than 75% and 70% on SVLs and CBVLs, respectively. Scanning electron microscopy investigation revealed numerous and spread MG63 cells after 48h on SVL modified Ti surface and a lower cell adhesion on samples coated with CBVL. The cellular uptake capability of liposome content was proved by fluorescence microscopy using carboxyfluorescein loaded SVLs and CBVLs. Finally, we demonstrated that these liposome-modified Ti surfaces were able to deliver a model bioactive molecule (phosphatidylserine) to adherent cells, confirming the potentiality of developed systems in bone related prosthetic applications.

We report on the preparation of luminescent collectors based on poly(methyl methacrylate) (PMMA) thin films doped with a red-emitting 2-amino-7-acceptor-9-silafluorene, where the amino group is -N(CH3)(2) and the acceptor is -CH=C(CN)(2). The results obtained from photophysical investigations of the dye in different solvents and in PMMA are very encouraging as the silafluorene dyes turn out to be highly dispersed in the solid matrix, stable upon irradiation and highly emissive. QY and lifetime investigations demonstrate that autoabsorption phenomena moderately occur with SilaFluo content, and the optical features still maintained very significant, also at the highest fluorophore concentration (QY similar to 65%). Study of the LSCs features yields excellent optical efficiencies of 9.6% attained for 25 mm thick PMMA films containing the 1.5 wt% of SilaFluo. This performance is at the top level with respect to the current state-of-art of similar devices based on perylene-based fluorophores such as Lumogen Red.

The low photostability of conventional organic dyes and the toxicity of cadmium-based luminescent quantum dots have prompted the development of novel probes for in vitro and in vivo labelling. Here, a new fluorescent lanthanide probe based on silica nanoparticles is fabricated and investigated for optically traceable in vitro translocator protein (TSPO) targeting. The targeting and detection of TSPO receptor, overexpressed in several pathological states, including neurodegenerative diseases and cancers, may provide valuable information for the early diagnosis and therapy of human disorders. Green fluorescent terbium(III)-calix[4]arene derivative complexes are encapsulated within silica nanoparticles and surface functionalized amine groups are conjugated with selective TSPO ligands based on a 2-phenylimidazo[1,2-a]pyridine acetamide structure containing derivatizable carboxylic groups. The photophysical properties of the terbium complex, promising for biological labelling, are demonstrated to be successfully conveyed to the realized nanoarchitectures. In addition, the high degree of biocompatibility, assessed by cell viability assay and the selectivity towards TSPO mitochondrial membrane receptors, proven by subcellular fractional studies, highlight targeting potential of this nanostructure for in vitro labelling of mitochondria.

The urgent demand for low-cost green clean energy has stimulated the research for new materials for energy storage and conversion. Colloidal semiconductor nanocrystals (NCs) were demonstrated as promising materials for light harvesting applications, while nanostructured titanium dioxide (TiO2) has been successfully exploited in electrodes for photovoltaics (PV). In particular, NCs with controlled size and shape, coupled and/or functionalized with suitable organic chromophores proved efficient energy transfer (ET) and charge transfer (CT) processes [3]. Understanding the events occurring at organic/inorganic interfaces in both ET and CT processes is crucial for the direct application of the developed materials in real devices. In this work, CdSe NCs of selected size, synthesized by hot-injection methods [4], were coupled with an organic chromophore, based on boron-dipyrromethene (BODIPY) dye, properly functionalized with amino groups to improve its affinity with NC surface. The spectroscopic investigations on such hybrid nanosystems in solution revealed a FRET process occurring between the NCs acting as donor to the conjugated dye molecules. A remarkable increase of the FRET efficiency was obtained for the coupled nanosystems deposited on substrate, with respect to the layered thin films of NCs and dye, indicating a favourable influence of the reduced interparticle separation. In addition, TiO2 NCs and a zinc phthalocyanine functionalized with carboxylic acid groups (PcTC) were selected to investigate CT processes, due to proper band alignment. The hybrid composite was prepared in solution and in solid state, by exploiting both simple physisorption and effective chemical bond formation after activation of the carboxylic acid functionalities. The quenching of the PcTC fluorescence suggested the emergence of CT. In particular, in the solutionphase nano-hybrids, CT efficiency and stability were sensitive to the nature of the solvent, as well as to the preparation strategy.

The urgent demand for low-cost green clean energy has stimulated the research for new materials for energy storage and conversion. Colloidal semiconductor nanocrystals (NCs) were demonstrated as promising materials for light harvesting applications, while nanostructured titanium dioxide (TiO2) has been successfully exploited in electrodes for photovoltaics. In particular, NCs with controlled size and shape, coupled and/or functionalized with suitable organic chromophores demonstrated efficient energy transfer (ET) and charge transfer (CT) processes. Understanding the events occurring at organic/inorganic interfaces in both ET and CT processes is crucial for the direct application of the developed materials in real devices. In this work, CdSe NCs of selected size, synthesized by hot-injection methods, were coupled with organic chromophores, based on boron-dipyrromethene (BODIPY) dye, properly functionalized with amino groups to improve their affinity with NC surface. The spectroscopic investigations on such hybrid nanosystems in solution revealed a FRET process occurring between the NCs (donor) to the conjugated dye. A comparative study was performed, to evaluate the effect of the substitution extent at the BODIPY rings on the ability of the two dyes to effectively support the ET process. Experimental results show that the mono-functionalization with an amino-styryl group both provides an improved spectral overlap between the NCs emission and dye absorption and a shorter donor-acceptor separation distance, resulting in higher FRET efficiency with respect to the hybrid based on the bi-functionalized dye. A remarkable increase of the FRET efficiency was obtained for the coupled nanosystems deposited on substrate, with respect to the layered thin films of NCs and dye, indicating a favourable influence of the reduced interparticle separation. In addition, TiO2 NCs and a Zn phthalocyanine functionalized with carboxylic acid groups (PcTC) were selected to investigate CT processes, due to proper band alignment. The hybrid composite was prepared in selected to investigate CT processes, due to proper band alignment. The hybrid composite was prepared in solution and in solid state, by exploiting both simple physisorption and effective chemical bond formation after activation of the carboxylic acid functionalities. The quenching of the dye fluorescence suggested the emergence of CT. In particular, in the solution-phase nano-hybrids, CT efficiency and stability were sensitive to the nature of the solvent, as well as to the preparation strategy.

Metal halide perovskites nanocrystals (NCs) represent an emerging class of materials that find increasing application in optoelectronic and photovoltaic devices, thanks to their intriguing optical properties, including high absorption coefficient, high fluorescence quantum yield (PL QY) and fast charge carrier separation. However, their opening to market is still hindered by their limited reliability, due to an intrinsic structural instability and degradation of their photophysical properties upon air, moisture, and light exposure. The incorporation of perovskite NCs in polymer matrix can limit some of the NC instability issues, with advantages in film processability, device fabrication and mechanical performance, being also useful for fundamental studies. In this regard, here, nanocomposites based on polymethylmethacrylate or polystyrene embedding all-inorganic CsPbBr3 NCs have been prepared and processed in the form of flexible free-standing films. A systematic spectrofluorimetric study, comprising steady state photoluminescence (PL), PL quantum yield (QY) and PL decay of the free-standing films before and after exposure to relative humidity condition (RH% 85%, at 25 &deg, C) is performed and discussed. Phase segregation phenomena, changes in NC passivation and recombination dynamics are evaluated as a function of polymer loading and its molecular structure and finally the efficacy of the polymer as moisture barrier investigated.

Fabrication of heterostructures by merging two or more materials in a single object. The domains at the nanoscale represent a viable strategy to purposely address materials&rsquo, properties for applications in several fields such as catalysis, biomedicine, and energy conversion. In this case, solution-phase seeded growth and the hot-injection method are ingeniously combined to fabricate TiO2/PbS heterostructures. The interest in such hybrid nanostructures arises from their absorption properties that make them advantageous candidates as solar cell materials for more efficient solar light harvesting and improved light conversion. Due to the strong lattice mismatch between TiO2 and PbS, the yield of the hybrid structure and the control over its properties are challenging. In this study, a systematic investigation of the heterostructure synthesis as a function of the experimental conditions (such as seeds&rsquo, surface chemistry, reaction temperature, and precursor concentration), its topology, structural properties, and optical properties are carried out. The morphological and chemical characterizations confirm the formation of small dots of PbS by decorating the oleylamine surface capped TiO2 nanocrystals under temperature control. Remarkably, structural characterization points out that the formation of heterostructures is accompanied by modification of the crystallinity of the TiO2 domain, which is mainly ascribed to lattice distortion. This result is also confirmed by photoluminescence spectroscopy, which shows intense emission in the visible range. This originated from self-trapped excitons, defects, and trap emissive states.

2D electronic spectroscopy maps acquired in different configurations unveil intraband hot carrier cooling and interband multi-exciton recombination dynamics., Although the harnessing of multiple and hot excitons is a prerequisite for many of the groundbreaking applications of semiconductor quantum dots (QDs), the characterization of their dynamics through conventional spectroscopic techniques is cumbersome. Here, we show how a careful analysis of 2DES maps acquired in different configurations (BOXCARS and pump–probe geometry) allows the tracking and visualization of intraband Auger relaxation mechanisms, driving the hot carrier cooling, and interband bi- and tri-exciton recombination dynamics. The results obtained on archetypal core–shell CdSe/ZnS QDs suggest that, given the global analysis of the resulting datasets, 2D electronic spectroscopy techniques can successfully and efficiently dispel the intertwined dynamics of fast and ultrafast recombination processes in nanomaterials. Hence, we propose this analysis scheme to be used in future research on novel quantum confined systems.

Carbon dots (C-dots) are emerging as new emitting nanomaterials for optoelectronics, bioimaging, and biosensing thanks to their high quantum yield (QY), biocompatibility, low toxicity, and cost-effective sources. Although the origin of their photoluminescence (PL) mechanism (i.e., their strong blue-green emission and excitation dependent fluorescence) is still controversial, it has been demonstrated to depend on the synthetic protocols and experimental conditions, able to Modify the surface properties. Here oil-dispersible C-dots, synthesized by carbonization of citric acid in the presence of hexadecylamine in high boiling organic solvent, are thoroughly investigated by systematically controlling the synthetic reaction parameters. Similarly to what was found for water-soluble C-dots, citric acid in the presence of amine-containing passivating agents improves the PL emission of-C-dots via the formation of molecular fluorescent derivatives alongside the carbonization process. We demonstrate that at, growth temperature of 200 degrees C such C-dots exhibit an interesting and intense white emission, when excited in the blue region, thus resulting, in a biocompatible colloidal white emitting single nano-objects. The incorporation of the nanoparticles in a poly(methyl methacrylate) (PMMA) host matrix, to obtain free-standing nanocomposite films, is demonstrated not to affect the color point, which still falls in the white color region of the 1931 CIE diagram. Remarkably, the emission properties are retained even after several months of films exposure to air and sunlight, thus confirming the color stability of the nanoparticles against aging.

This study reports for the first time the use of a red-emitting AIEgen, i.e. TPE-AC, for the realization of efficient luminescent solar concentrators (LSCs) based on poly(methyl methacrylate) (PMMA) and polycarbonate (PC) thin films (25 +/- 5 mu m). TPE-AC is an AIEgen with D-A features that absorbs visible light in the range between 400 and 550 nm and emits fluorescence peaked at 600-620 nm, with a maximum quantum yield (QY) of 50% when dispersed (0.1-1.5 wt%) in PMMA and PC matrices. QY and lifetime investigations demonstrated that fluorescence quenching occurred with varying the TPE-AC concentration, even if the optical features were still significant even at the highest fluorophore content. Study of the LSCs' performances yielded worthy optical efficiencies of 6.7% for the TPE-AC/PC systems due to their superior light harvesting features and the compatibility of the AIEgen within the PC matrix.

Nanocrystalline titania (TiO2) synthesized via sol–gel, by using an alkoxide precursor were deposited onto commercially available silica and alumina fibers, namely E-Glass and Nextel 650, respectively. Different processing conditions and material preparation parameters, such as amount of TiO2, film composition and annealing temperature were tested in order to obtain nanocrystalline TiO2 with different morphological and structural characteristics. The materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and the Brunauer, Emmett, and Teller (BET) surface area measurements. The photocatalytic activity of the obtained coated fibers was investigated by monitoring the degradation of a model molecule, an azo dye (Methyl Red), under UV irradiation in aqueous solution. The detected photocatalytic performance of the sol–gel derived nanocrystalline TiO2 was explained on the basis of mechanism associated to the photocatalytic decomposition of organic molecules using semiconductor oxides and accounted for the structural and morphological characteristics of the TiO2 based coating. The materials with the most suited characteristics for photocatalysis were used to scale up the deposition onto a larger sample of fiber and then tested in a photocatalytic reactor. A commercially available TiO2 standard material (TiO2 P25 Degussa) was used as reference, in order to ultimately assess the viability of the coating process for real application.

Fluorescent polystyrene microspheres are prepared by the incorporation of fluorescent CdSe/CdS core/shell semiconductor nanocrystals (quantum dots, QDs) using the emulsification/solvent evaporation method. The radiative exciton recombination dynamics is investigated by nanosecond time-resolved fluorescence spectroscopy at ambient conditions. The time constants of fast and slow fluorescence decay in QDs, dispersed in toluene, were 3.5 and 17.8 ns, respectively. For the QD-tagged microspheres, the time constants of fast and slow processes were ~2–3 and ~11–12 ns, respectively, and did not depend significantly on the QD-content of the microspheres. The fast decay component could be attributed to the recombination of delocalized exciton in the internal core states, and the slow component was attributed to the localized exciton in the surface states. It was found that the ratio of amplitudes of the fast and slow processes also changed after incorporation of QDs in microspheres. The observed differences in fluorescence decay between non-entrapped QDs and QD-tagged microspheres were probably due to energy transfer between the nanocrystals, which were in close proximity inside the microspheres. The obtained fluorescent QD-tagged microspheres are characterized by the other methods as well, which makes them of value for various applications as optical materials.

The unique size- and shape-dependent electronic properties of nanocrystals (NCs) make them extremely attractive as novel structural building blocks for constructing a new generation of innovative materials and solid-state devices. Recent advances in material chemistry has allowed the synthesis of colloidal NCs with a wide range of compositions, with a precise control on size, shape and uniformity as well as specific surface chemistry. By incorporating such nanostructures in polymers, mesoscopic materials can be achieved and their properties engineered by choosing NCs differing in size and/or composition, properly tuning the interaction between NCs and surrounding environment. In this contribution, different approaches will be presented as effective opportunities for conveying colloidal NC properties to nanocomposite materials for micro and nanofabrication. Patterning of such nanocomposites either by conventional lithographic techniques and emerging patterning tools, such as ink jet printing and nanoimprint lithography, will be illustrated, pointing out their technological impact on developing new optoelectronic and sensing devices.

We introduce a new method for the prompt and effective evaluation of the optical efficiency of different sets of luminescent solar concentrators (LSC) based on dye-doped poly(methyl methacrylate) thin films. The procedure founded on the realization of a home-build apparatus (PeryRoom), which allowed for a fast and reliable measurement of the generated photocurrents profiting of the use of a photodiods system. The photocurrents were analyzed by means of a simple model inspired by the work of Goetzberger and Greube (1977) and rationalized in terms of different dye characteristics and film thickness. The procedure was eventually validated by comparing the optical efficiencies measured by using a Si-based photovoltaic module. Overall, the present results support the use of PeryRoom for the optimization of the current state-of-art LSC systems.

Liposomes are small vesicles that spontaneously form when lipid molecules are dispersed in an aqueous medium. Their appeal derive from composition, which makes them biocompatible and biodegradable. Therefore, they arouse great interest from researchers as ideal carriers for biomedical imaging, drug delivery, targeted therapy, biosensing and more. We used liposome systems for the realization of new hybrid biocompatible materials, such as carriers for drug and bioactive molecule delivery, vesicle-encapsulated nanocrystals (NCs) for bioimaging applications and biomimetic functionalized surface for prosthetic purposes.

International audience; Polymeric ionic liquids (PILs) are an interesting class of polyelectrolytes, merging peculiar physical-chemical features of ionic liquids with the flexibility, mechanical stability and processability typical of polymers. The combination of PILs with colloidal semiconducting nanocrystals leads to novel nanocomposite materials with high potential for batteries and solar cells. We report the synthesis and properties of a hybrid nanocomposite made of colloidal luminescent CdSe nanocrystals incorporated in a novel ex situ synthesized imidazolium-based PIL, namely, either a poly(N-vinyl-3-butylimidazolium hexafluorophosphate) or a homologous PIL functionalized with a thiol end-group exhibiting a chemical affinity with the nanocrystal surface. A capping exchange procedure has been implemented for replacing the pristine organic capping molecules of the colloidal CdSe nanocrystals with inorganic chalcogenide ions, aiming to disperse the nano-objects in the PILs, by using a common polar solvent. The as-prepared nanocomposites have been studied by TEM investigation, UV-Vis, steady-state and time resolved photoluminescence spectroscopy for elucidating the effects of the PIL functionalization on the morphological and optical properties of the nanocomposites.

We investigated the excitation density dependence of the photoluminescence spectra of hybrid poly(9,9-dioctylfluorene)-CdSe/ZnS nanocrystals (PF8-NCs) thin films. We demonstrate that this experiment allows the determination of the efficiency of all the CdSe/ZnS NCs excitation processes and that the presence of amplified spontaneous emission (ASE) from the PF8 leads to a strong dependence of the NC excitation processes from the laser excitation density. Below the PF8 ASE threshold only about 6% of the excitons in the NCs are due to pump laser absorption, while about 94% of the NC excitation is due to the interaction with the PF8, and it is due for about 58% to PF8 -> NC Forster resonant energy transfer (FRET) and for about 37% to reabsorption by the NCs of the PF8 luminescence. ne presence of PF8 ASE significantly modifies this scenario by strongly decreasing the FRET importance and strongly increasing the reabsorption one. The interplay between reduced FRET and increased reabsorption overall decreases the NC excitation due to PF8 indicating that ASE from the donors should be avoided if efficient NCs excitation under strong pumping is wished.

Strong enhancements in the spontaneous emission intensity of dye chromophores-loaded in a printable polymer have been achieved by coupling the dye emission to surface plasmons of metallic thin films and metallic nanoparticles. The nanocomposite materials embossed by nanoimprint lithography process show good imprint properties.

A 1.7-fold enhancement in the spontaneous emission intensity of dye chromophore loaded in a printable polymer is achieved by coupling the dye emission to surface plasmons of metallic nanoparticles. The nanocomposite material, embossed into arrays of wires by nanoimprint lithography process, shows good imprint properties. The results prove the potential of the prepared luminescent functional materials for micro- and nanofabrication and suggest the use of nanocomposite materials in prospective nanoplasmonic applications.

Two colloidal methods, namely one pot and two steps approaches, have been exploited to synthesize light emitting CdSe/ZnS core-shell nanocrystals, differing in growth process of the inorganic ZnS shell and, therefore in the resulting surface chemistry of the two types of nanocrystals. The synthesized nanocrystals have been incorporated, by using an "ex situ" procedure, in different thermoplastic PMMA-based polymers, including PMMA co-polymer specifically functionalized by means of groups having high chemical affinity to nanocrystal surface, and the resulting nanocomposites have been processed in thin films. Spectroscopic steady state and time-resolved investigations, carried out both on nanocomposite solution and thin film samples, indicate as a change in the optical properties of the two steps nanocrystals is observed upon incorporation in polymers, especially in PMMA homopolymer, where significant aggregation of inorganic nanostructures occurs. On the contrary, the one pot CdSe/ZnS nanocrystals preserve in all investigated samples their long-lived radiative emission. Such nanocrystals result homogeneously dispersed in the polymers, providing high quality films and thus representing ideal candidates for future optical applications.