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Realizing semi-transparent perovskite solar cells for building applications is a very hard goal not only because the absorption and the transmission of light through the device are two competitive processes, but also because the Power Conversion Efficiency (PCE) decreases with the angle of incidence of sunlight rays due to the increased reflection intensity. Moreover, an Average Visible Transmittance (AVT) of 25% and PCE of 15% have to be overcome simultaneously in a wide angular range in order to penetrate the market of smart windows. Here, through a rational management of the p and s light reflection modes of a dielectric/metal/dielectric used as top-electrode, we realize a semi-transparent FAPbI3 perovskite solar cell with an AVT value of 28% without the detriment of the PCE, that remains over 15% in a broad angular range up to 50° from normal light-incidence, thus breaking the benchmarks for a real building integration.

The central dogma of molecular biology dictates that, with only a few exceptions, information proceeds from DNA to protein through an RNA intermediate. Examining the enigmatic steps from prebiotic to biological chemistry, we take another road suggesting that primordial peptides acted as template for the self-assembly of the first nucleic acids polymers. Arguing in favour of a sort of archaic “reverse translation” from proteins to RNA, our basic premise is a Hadean Hearth where key biomolecules such as amino acids, polypeptides, purines, pyrimidines, nucleosides and nucleotides were available under different prebiotically plausible conditions, including meteorites delivery, shallow ponds and hydrothermal vents scenarios. Supporting a protein-first scenario alternative to the RNA world hypothesis, we propose the primeval occurrence of short peptides termed “selective amino acid- and nucleotide-matching oligopeptides” (henceforward SANMAOs) that noncovalently bind at the same time the polymerized amino acids and the single nucleotides dispersed in the prebiotic milieu. We describe the chemical features of this hypothetical oligopeptide, its biological plausibility and its virtues from an evolutionary perspective. We provide a theoretical example of SANMAO’s selective pairing between amino acids and nucleosides, simulating a poly-Glycine peptide that acts as a template to build a purinic chain corresponding to the glycine’s extant triplet codon GGG. Further, we discuss how SANMAO might have endorsed the formation of low-fidelity RNA’s polymerized strains, well before the appearance of the accurate genetic material’s transmission ensured by the current translation apparatus.

Metal-halide semiconductor perovskites have received great attention for the development of stable and efficient light emitting diodes and lasers, since they combine high charge carrier mobility and light emission spectral-purity with low-cost fabrication methods. Nevertheless, the role of excitons, free carries and trap states in perovskite light emission properties is still unclear due to their interdependence. In this paper we selectively manage trapping and light emission mechanisms by a reversible laser-assisted trap-passivation process performed on a CH3NH3PbBr3 perovskite layer, coupled to the inner modes of a high-quality micro-cavity, which only affects the radiative recombination. We show that photoluminescence is dominated by exciton radiative decay process and that trap states passivation increases the exciton gemination rate by reducing coulombic scattering of free electrons due to the ionized impurities. This picture provides a more general description than the model based on trap states-free Saha thermodynamic equilibrium between photo-generated species. The interdependence of free carries, trap states and excitons in the light emission properties of CH3NH3PbBr3 perovskite thin films and their relationship to device performance is a subject of debate. Here, the authors investigate the role of non-radiative recombination and demonstrate that the photoluminescence is dominated by exciton radiative decay processes.

All-inorganic perovskites are widely investigated as a new generation of materials thanks to their superior optoelectronic properties and better stability than hybrid organic–inorganic perovskites. In particular, cesium lead bromide (CsPbBr3) exhibits advantageous properties for numerous applicative fields (photovoltaics, light-emitting diodes, photodetectors, lasing, field effect transistors, and ionizing radiation detectors). The performance of CsPbBr3 being critically dependent on the deposition technique, proper understanding and optimization of the fabrication process are demanding. Despite the well-known potentiality of the Pulsed Laser Deposition (PLD) technique in depositing films with complex stoichiometry, a very limited number of literature studies report on the successful deposition of CsPbBr3 films by PLD. Recently, the authors disclosed the impact of the uneven masses of Cs, Pb, and Br on the film stoichiometry and guidelines to recover the desired composition. Herein, we exploit stoichiometric mechano-chemically synthesized targets to deposit, by nanosecond-PLD (λ = 248 nm, τ = 20 ns, room temperature, fluence of 1 J/cm2), CsPbBr3 films to be studied following time aging, thermal heating and exposure to high relative humidity. Even in the presence of the characteristic absorption peak at ~ 520 nm, the freshly deposited film shows no photoluminescence. Photoluminescence is switched on by thermal annealing (at 250 and 350 °C) or after a few days (at least 15) of exposure to air and it persists over time. Films present interesting morphology evolution and oxygen adsorption following heating.

All-inorganic cesium lead bromine (CsPbBr3) perovskites have gained a tremendous potential in optoelectronics due to interesting photophysical properties and much better stability than the hybrid counterparts. Although pulsed laser deposition (PLD) is a promising alternative to solvent-based and/or thermal deposition approaches due to its versatility in depositing multi-elemental materials, deep understanding of the implications of both target composition and PLD mechanisms on the properties of CsPbBr3 films is still missing. In this paper, we deal with thermally assisted preparation of mechano-chemically synthesized CsPbBr3 ablation targets to grow CsPbBr3 films by PLD at the fluence 2 J/cm2. We study both Cs rich- and stoichiometric PbBr2-CsBr mixture-based ablation targets and point out compositional deviations of the associated films resulting from the mass distribution of the PLD-generated plasma plume. Contrary to the conventional meaning that PLD guarantees congruent elemental transfer from the target to the substrate, our study demonstrates cation off-stoichiometry of PLD-grown CsPbBr3 films depending on composition and thermal treatment of the ablation target. The implications of the observed enrichment in the heavier element (Pb) and deficiency in the lighter element (Br) of the PLD-grown films are discussed in terms of optical response and with the perspective of providing operative guidelines and future PLD-deposition strategies of inorganic perovskites.

Carbon dioxide (CO2)-laser processing of glasses is a versatile maskless writing technique to engrave micro-structures with flexible control on shape and size. In this study, we present the fabrication of hundreds of microns quartz micro-channels and micro-holes by pulsed CO2-laser ablation with a focus on the great potential of the technique in microfluidics and biomedical applications. After discussing the impact of the laser processing parameters on the design process, we illustrate specific applications. First, we demonstrate the use of a serpentine microfluidic reactor prepared by combining CO2-laser ablation and post-ablation wet etching to remove surface features stemming from laser-texturing that are undesirable for channel sealing. Then, cyclic olefin copolymer micro-pillars are fabricated using laser-processed micro-holes as molds with high detail replication. The hundreds of microns conical and square pyramidal shaped pillars are used as templates to drive 3D cell assembly. Human Umbilical Vein Endothelial Cells are found to assemble in a compact and wrapping way around the micro-pillars forming a tight junction network. These applications are interesting for both Lab-on-a-Chip and Organ-on-a-Chip devices.

Carbon dioxide (CO2)-laser processing of glasses is a versatile maskless writing technique to engrave micro-structures with flexible control on shape and size. In this study, we present the fabrication of hundreds of microns quartz micro-channels and micro-holes by pulsed CO2-laser ablation with a focus on the great potential of the technique in microfluidics and biomedical applications. After discussing the impact of the laser processing parameters on the design process, we illustrate specific applications. First, we demonstrate the use of a serpentine microfluidic reactor prepared by combining CO2-laser ablation and post-ablation wet etching to remove surface features stemming from laser-texturing that are undesirable for channel sealing. Then, cyclic olefin copolymer micro-pillars are fabricated using laser-processed micro-holes as molds with high detail replication. The hundreds of microns conical and square pyramidal shaped pillars are used as templates to drive 3D cell assembly. Human Umbilical Vein Endothelial Cells are found to assemble in a compact and wrapping way around the micro-pillars forming a tight junction network. These applications are interesting for both Lab-on-a-Chip and Organ-on-a-Chip devices., Graphical abstract Image 1, Highlights • Carbon dioxide-laser ablation was used for fast prototyping of quartz. • Serpentine microfluidic reactors were prepared after post-ablation wet etching. • Polymeric micro-pillars were fabricated using quartz micro-holes as molds. • Micro-pillars were used as templates to drive 3D assembly of Endothelial Cells. • Cells organize in a vessel-like configuration forming tight junctions.

The present study systematically investigates the morphology and crystallization process of inorganic CsPbBr

Aims Although oral anticoagulants (OACs) are effective in preventing stroke in older people with atrial fibrillation (AF), they are often underused in this particularly high-risk population. The aim of the present study was to assess the appropriateness of OAC prescription and its associated factors in hospitalized patients aged 65 years or older. Methods Data were obtained from the retrospective phase of Simulation-based Technologies to Improve the Appropriate Use of Oral Anticoagulants in Hospitalized Elderly Patients With Atrial Fibrillation (SIM-AF) study, held in 32 Italian internal medicine and geriatric wards. The appropriateness of OAC prescription was assessed, grouping patients in those who were and were not prescribed OACs at hospital discharge. Multivariable logistic regression was used to establish factors independently associated with the appropriateness of OAC prescription. Results A total of 328 patients were included in the retrospective phase of the study. Of these, almost 44% (N = 143) were inappropriately prescribed OACs, being mainly underprescribed or prescribed an inappropriate antithrombotic drug (N = 88). Among the patients prescribed OACs (N = 221), errors in the prescribed doses were the most frequent cause of inappropriate use (N = 55). Factors associated with a higher degree of patient frailty were inversely associated with the appropriateness of OAC prescription. Conclusions In hospitalized older patients with AF, there is still a high prevalence of inappropriate OAC prescribing. Characteristics usually related to frailty are associated with the inappropriate prescribing. These findings point to the need for targeted interventions designed for internists and geriatricians, aimed at improving the appropriate prescribing of OACs in this complex and high-risk population.

Poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) based organic electrochemical transistors (OECTs) have been widely applied in bioelectronics because of their low power consumption, biocompatibility, and ability to convert ionic biological signals into electronic signals with high sensitivity. Here, the processing of PEDOT:PSS thin films on soft substrates is reported for stretchable OECT applications. Enhanced stretchability of PEDOT:PSS films on elastic substrates is obtained by synergistically reducing the film thickness and decreasing the baking temperature. The resultant films, together with ultrathin Au electrodes, enable the assembling of fully stretchable OECTs using conventional fabrication techniques, without prestretching the substrates. The stretchable OECTs maintain similar electrical characteristics within 30% applied strain. It is also demonstrated that brittle PEDOT:PSS films, which are not suitable for making stretchable OECTs, can be used for transparent pressure sensors.

Aims To assess the appropriateness of oral anticoagulant (OAC) prescription and its associated factors in acutely hospitalized elderly patients. Methods Data were obtained from the prospective phase of SIM-AF (SIMulation-based technologies to improve the appropriate use of oral anticoagulants in hospitalized elderly patients with Atrial Fibrillation) randomized controlled trial, aimed to test whether an educational intervention improved OAC prescription, compared to current clinical practice, in internal medicine wards. In this secondary analysis, appropriateness of OAC prescription was assessed at hospital admission and discharge. Results For 246 patients, no significant differences were found between arms (odds ratio 1.38, 95% confidence interval [CI] 0.84-2.28) in terms of appropriateness of OAC prescription. Globally, 92 patients (37.4%, 95% CI = 31.6-43.6%) were inappropriately prescribed or not prescribed at hospital discharge. Among 51 patients inappropriately prescribed, 82% showed errors on dosage, being mainly under-dosed (n = 29, 56.9%), and among 41 inappropriately not prescribed, 98% were taking an antiplatelet drug. Factors independently associated with a lower probability of appropriateness at discharge were those related to a higher risk of bleeding (older age, higher levels of aspartate aminotransferase, history of falls, alcohol consumption) and antiplatelet prescription at admission. The prescription of OACs at admission was the strongest predictor of appropriateness at discharge (odds ratio = 7.43, 95% CI = 4.04-13.73). Conclusions A high proportion of hospitalized older patients with AF remains inappropriately prescribed or nonprescribed with OACs. The management of these patients at hospital admission is the strongest predictor of prescription appropriateness at discharge.

The realization of a highly efficient and transparent light-emitting display isan ambitious but highly desirable goal since several obstacles need to be solved. One of the most challenging issues is the fabrication of a suitable transparent cathode on the top emitting surface. Evaporated Ca thin film is one theoretically promising candidate due to its remarkable optical transparency, conductivity, and matched work function (WF) on the electron injection side. However, until now, keeping metallic Ca working as a stand-alone electrode is not possible because its highly reactive characteristics cause ultrathin Ca film to react with organics. In this work, atomic layer deposition ZnO is presented with the intention of protecting a vulnerable ultrathin Ca layer while preserving its low WF in the entire structure. In this research, a transparent cathode that maintains a low WF of 3.31 eV is built, enabling highly transparent (nearly 90% in the visible range) organic light-emitting diodes with external quantum efficiencies that reach 22.7%, 19.3%, and 17.9% for green, yellow, and blue emissions, respectively, and reaching an emission balance. The luminance of the devices is about three times higher when compared with the devices without protective structures, which are even likely to fail to operate.

The integration of energy-saving electrochromic systems with novel functions and features in a single smart multifunctional device promises to achieve remarkable technological advancements for a wide range of consumer products showing more versatility, responsivity to different external inputs, and ability to operate in interactive modes. Here, we report a novel architecture in which a solid-state electrochromic cell and a solid-state organic light emitting diode are fully integrated in a single, highly transparent, solid-state electrochromic OLED device. This multifunctional device is capable of tuning its optical properties such as transmittance (chromic transition) and of producing light by electroluminescence, simultaneously or independently. The rational design of the solid-state electrochromic cell and the highly transparent OLED enables the construction of the integrated device in a monolithic unit. In such a structure the photonic architecture of the OLED device not only guarantees high transmittance, but, operating synergically with the electrochromic component, it outperforms the optical properties and electrochromic responses by the interference phenomenon, achieveing an optical contrast of 57% (ΔTbleaching/colouring @ 650 nm), and a coloration efficiency of 169 cm2 C−1, with very low energy consumption (80 mW cm−2). The OLED component exhibits luminance above the minimum values required for display and lighting applications, which are 300 cd m−2 and above 800 cd m−2, respectively. This result represents a further step towards the development of next-generation multifunctional EC devices such as full solid-state photoelectrochromic devices, and, importantly, this can open the way for new electrochromic “smart” window systems such as retail display windows or display EC glasses for augmented reality.

A Fabry-Perot microcavity with a high quality Q-factor is an excellent tool to finely tune and narrow the emission spectrum of embedded organic dyes, leading also to a modification of the radiative emission rate (Purcell effect). For a real application of these properties in light emitting diodes and lasers, high Q-factors should be also provided in electrically-driven organic microcavities, that is still a challenge when organic materials are employed. Metallic contacts can be safely deposited onto organic layers, although they result in strong absorption losses. In this work, we successfully integrated an Organic LED architecture within specifically tailored metal-free electrically active Bragg mirrors, finely optimized to achieve simultaneously high reflectivity and good electrical properties. The resulting electroluminescent microcavity showed a Q-factor of more than 200 (emission linewidth of 2.7 nm at a peak wavelength of 555 nm) and a clear proof of the occurrence of Purcell effect leading to a decrease of exciton radiative lifetime by a factor above 6. Finally, we analysed the parameters that still limit the Q-factor of our architecture, paving the way for future improvements. The proposed approach can be exploited for the fabrication of novel monochromatic organic light sources for telecommunications or biological sensing and it represents an important step towards the realization of electrically driven organic lasers.

Silver nanowires (AgNWs) are a promising candidate to replace indium tin oxide (ITO) as transparent electrode material. However, the loose contact at the junction of the AgNWs and residual surfactant polyvinylpyrrolidone (PVP) increase the sheet resistance of the AgNWs. In this paper, an argon (Ar) plasma treatment method is applied to pristine AgNWs to remove the PVP layer and enhance the contact between AgNWs. By adjusting the processing time, we obtained AgNWs with a sheet resistance of 7.2Ω/□ and a transmittance of 78% at 550 nm. To reduce the surface roughness of the AgNWs, a peel-off process was used to transfer the AgNWs to a flexible NOA63 substrate. Then, an OLED was fabricated with the plasma-treated AgNWs electrode as anode. The highest brightness (27000 cd/m2) and current efficiency (11.8 cd/A) was achieved with a 30 nm thick light emitting layer of tris-(8-hydroxyquinoline) aluminum doped with 1% 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5 H,11H-(1)-benzopyropyrano(6,7-8-I,j)quinolizin-11-one. Compared to thermal annealing, the plasma-treated AgNW film has a lower sheet resistance, a shorter processing time, and a better hole-injection. Our results indicate that plasma treatment is an effective and efficient method to enhance the conductivity of AgNW films, and the plasma-treated AgNW electrode is suitable to manufacture flexible organic optoelectronic devices.

Incubating in the rise of perovskite photovoltaic era, the advances in material design encourage further promising optoelectronic exploitations. Here, we evaluate halide perovskite envisioning light-emitting applications, with a particular focus to the role that this material can effectively play in the field, discussing advantages and limitations with respect to state of art competing players. Specific benefits derive from the use of low dimensional and nanostructured perovskites, marginally exploited in photovoltaic devices, allowing for a tuning of the excited states properties and for the obtainment of intrinsic resonating structures. Thanks to these unique properties, halide perovskite ensure a great potential for the development of high-power applications, such as lighting and lasing.

The development of alternative deposition techniques of conjugated polymeric compounds is an important step towards the fabrication of low cost multi-layered organic light emitting diodes suitable for display or lighting applications. In this work we show a white light -emitting polymeric hetero-structured diode consisting of three-stacked blue, red and green light emitting polymers. In order to circumvent the issue of selecting orthogonal solvents in solution -deposition approaches, we combine spin-coating with the Matrix Assisted Pulsed Laser Evaporation technique, resulting in the realization of a polymeric multilayered stack. By controlling the carriers and the energy transfer across the three light emitting layers interfaces, as well as the interplay between the deposition parameters, a pure white colour emission with Commission Internationale de l'Éclairage coordinates (X=0.327, Y=0.374) and a Color Rendering Index of 70 have been achieved. Our study represents the first proof of a light emitting diode made by multilayer polymeric thin films emitting white light.

A scientific theory is not a speculation. On the contrary it is based on facts and observations. Nevertheless the facts and the observations are unable to show us the truth about the world. Indeed to understand the facts or even to discover them through experiments we need a starting theory about the world. Therefore the world is not only discovered by us, but we can say that it is created by our brain. Facts are the constraints for the possible theories and theories are creations of our minds to understand the facts. There are no facts without a theory in mind, and there are no scientific theories about the world without facts. It is obvious therefore that science cannot give any absolute truth but “only” temporary truths which will change with new discoveries and theories. The scientific truth is therefore unstable: after few decades the concepts become unable to explain the news discoveries and become old, but the new concepts will include the old ones. This is called science progress. In this work we analyze all these points discussing the historical creation of the gravitational theory from Aristotle to Newton.

New random poly(arylene-vinylene)s obtained by combining different amounts of benzo[2,1,3]thiadiazole units with 9,9-dialkylfluorene and/or 1,4-dialkoxybenzene building blocks were synthesized by the Suzuki-Heck polymerization and characterized for use in bulk hetero-junction solar cells. Their optical, electrochemical, morphological and photovoltaic features were investigated. Notwithstanding the relatively low weight-average molecular weights of the obtained polymers (7000-13000 Da), they formed good quality films by spin-coating. UV-Vis measurements permitted the evaluation of their band gap (1.77-2.12 eV), enabling them to harvest a broad portion of the solar spectrum from 350 nm to 650 -700 nm. An electrochemical study revealed that the copolymers are endowed with HOMO/LUMO energy levels suitable for both an efficient electron transfer and a high open circuit voltage (V(oc)) for devices embodying the polymer/PCBM blends. This investigation pinpoints the important role of the copolymer composition (in terms of molar ratio of the monomeric units) on the performance of the donors in BHJs. In fact, in disagreement with the presumed V(oc) and current densities, the terpolymer poly [1,4-bis(2-ethylhexyloxy)-2,5-phenylene-vinylene-co-9,9-bis(2-ethylhexyl)-2,7-fluorenylene-vinylene-co-4,7-benzo[2,1,3]thiadiazolylene-vinylene] showed the best performance of the copolymer series, with a PCE of 0.4% and a V(oc) of 0.76 V, probably due to the favorable phase separation in the blend and consequently a better exciton dissociation. (c) 2011 Elsevier Ltd. All rights reserved.

We have developed a totally dry technique for the deposition of colloidal semiconductor nanocrystals on organic substrates. This approach is fully compatible with current organic LED technology. It appears that the slow evaporation of drop-cast QD films is critical for the success of the transfer process. This novel approach has been utilized to fabricate a hybrid organic–inorganic red LED

À Francesca Piazza et Mauro Serra,après une année de boxe avec la vie. 1. Pourquoi Muhammed Ali ? Muhammed Ali est une figure exceptionnelle : il est en même temps boxeur et orateur, protagoniste de performances athlétiques et verbales. L’analyse de la rhétorique de Muhammed Ali, à travers deux déclarations ou, pour mieux dire, deux compositions poétiques de blâme, de provocation et de défi, nous donnera la possibilité de découvrir, au milieu du xxe siècle, une modalité rhétorique de « la mis...

In this work, we explore the effects of the ultrastrong coupling regime between light and molecular excitons on the electrical and optical properties of microcavity-OLEDs. We studied two different samples having a coupling value of 31% and 48%. The main effect of the ultrastrong interaction is on the electroluminescent emission linewidth which was only 28 meV, that is about 12-fold narrower than that of the corresponding photoluminescence of the uncoupled material and even half the linewidth of photonic (weak-coupled) microcavity working at the same wavelength.

The matrix assisted pulsed laser evaporation (MAPLE) technique is emerging as an alternative route to conventional deposition methods of organic materials (solution-phase and thermal evaporation approaches). However, the high surface roughness of the films deposited by MAPLE makes this technique not compatible with applications in electronics and photonics. In this paper we report the deposition of MAPLE-films of a green light emitting polymer, commercially named ADS125GE, with remarkable low roughness values, down to about 10 nm at the thickness conventionally used in photonic devices (similar to 40 nm). This issue is discussed as a function of polymer concentration, target-substrate distance and substrate rotation based on AFM topography images, roughness estimation and optical (absorption and luminescent) measurements. In addition we have fabricated an organic light emitting diode with this technique using the best deposition parameters which guarantee the lowest roughness. These results open the way to MAPLE applications in organic photonics and opto-electronics.

We show, by accurate scattering calculations, that nanostructures obtained from thin films of J-aggregate dyes, despite their insulating behavior, are able to concentrate the electromagnetic field at optical frequencies like metallic nanoparticles. These results promise to widely enlarge the range of plasmonic materials, thus opening new perspectives in nanophotonics. Specifically we investigate ultrathin nanodisks and nanodisk dimers that can be obtained by standard nanolithography and nanopatterning techniques. These molecular aggregates display highly attractive nonlinear optical properties, which can be exploited for the realization of ultracompact devices for switching by light on the nanoscale without the need of additional nonlinear materials.

We study the optical properties of dithienothiophene functionalized with lateral dimesitylboryl groups and/or oxygen atoms at the central thienyl sulphur atom. The excitation energies, of these systems are computed using first-principles time-dependent density functional theory, and the results are discussed and compared with measured absorption spectra. The agreement between theoretical and experimental results is very good. It is found that the oxygen and the boron functionalization modifies the lowest unoccupied molecular orbital, and thus optical properties, in a different way. Moreover if the boron and the oxygen functionalization are combined together, the effects of the former dominate. (c) 2006 Elsevier B.V. All.rights reserved.

The synthesis via the Stille coupling of a new family of oligomers derived from benzo[b]thiophene is reported. Owing to their branched molecular structure lacking any symmetry element, these compounds display a low tendency to crystallization and better film-forming properties than their linear counterparts. Spin-coated films show photoluminescence efficiencies up to 50 %. Light-emitting diodes with spin-coated films as the active layers display markedly improved performance with respect to similar devices based on linear oligothiophenes, with luminance values up to more than 10000 cd m - 2 . Semiempirical PM3 and ZINDO/S calculations provide insight into the molecular geometries and electron distribution of the frontier orbitals of the new compounds. Cyclic voltammetry data indicates that the transformation of the thienyl sulfur of benzo[b]thiophene to the corresponding thienyl-S,S-dioxide leads an increase in electron affinity by 0.5-0.7 V, analogous to that of the corresponding linear oligomers.

We report on the fabrication of hybrid organic-inorganic vertical microcavities by using imprint lithography tools. The device consists of an organic active layer (rubrene-PMMA blend) embedded between two dielectric distributed Bragg reflectors (DBR). The active organic layer was spin coated on the first DBR, whereas a SU8 lithographic pattern was realized on the second DBR, which was used as the imprint mold. The two parts were then assembled together in an imprint process in order to create a vertical microcavity constituted by the rubrene active layer between two high-reflectivity mirrors. The effectiveness of this technology is demonstrated by the room temperature photoluminescence spectra, recorded on the fabricated microcavity, which show a sharp emission peak at the microcavity resonance wavelength.

The integration of a plasmonic lamellar grating in a heterostructure organic solar cell as a light trapping mechanism is investigated with numerical Finite Elements simulations. A global optimization of all the geometric parameters has been performed. The obtained wide-band enhancement in optical absorption is correlated with both the propagating and the localized plasmonic modes of the structure, which have been identified and characterized in detail. (c) 2012 Optical Society of America

Thermal evaporation of green-light emitting perovskite (MaPbBr3) films is reported. Morphological studies show that a soft thermal treatment is needed to induce an outstanding crystal growth and film organization. Hetero-structured light-emitting diodes, embedding as-deposited and annealed MAPbBr3 films as active layers, are fabricated and their performances are compared, highlighting that the perovskite evolution is strongly dependent on the growing substrate, too.