Formamidinium Perovskite Deposition in Ambient Air Environment for Inverted p-i-n Solar Cells.

In order to move towards large-scale fabrication, perovskite solar cells need to detach themselves from strictly controlled environmental conditions and, to this end, fabrication in ambient air is highly desirable. Formamidinium iodide perovskite (FAPI) is one of the most promising perovskites but is also unstable at room temperature, which may make the ambient air deposition more difficult. Herein, we investigated different formulations of pure FAPI for the fabrication of perovskite solar cells (PSCs) in air. We found that formulations using a mixture of N,N-Dimethylformamide (DMF): N-methyl-2-pyrrolidone (NMP) and only dimethyl sulfoxide (DMSO) are suitable for the deposition in air. To fabricate inverted p-i-n solar cells, we tested different hole transporting layers (HTLs) and observed the effects on the wettability of the perovskite solution and on the performance. A self-assembly monolayer of 2PACz (2-(9H-Carbazol-9-yl)ethyl]phosphonic acid) was found to be the best option as a HTL, allowing us to achieve efficiencies >15% on both FTO and ITO.

Mimicking Natural Antioxidant Systems for Improved Photostability in Wide-Band-Gap Perovskite Solar Cells.

Fostered by the top power conversion efficiencies (PCEs) of lab-scale devices, industrialization of perovskite solar cells is underway. Nevertheless, the intrinsically poor stability of these materials still represents a major concern. Herein, inspired by Nature, the use of ß-carotene in perovskite solar cells is proposed to mimic its role as a protective pigment, as occurs in natural photosynthesis. Laser-mediated photostability (LMPS) assessment, Fourier-transform infrared spectra analysis acquired in attenuate total reflectance (ATR-FTIR), spectroscopy ellipsometry (SE), and time-resolved photoluminescence (TRPL) measurements under stress conditions prove that the inclusion of a thin ß-carotene interlayer promotes a high improvement in the photostability of the perovskite films against photooxidation. Importantly, this is accompanied by an improvement of the solar cell PCE that approaches 20% efficiency with no hysteresis, which is among the highest values reported for a mixed halide (I-Br) perovskite with a band gap of 1.74 eV, relevant for coupling with silicon in tandem cells.

Pulsed Laser Deposition of CsPbBr3 Films: Impact of the Composition of the Target and Mass Distribution in the Plasma Plume.

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.

Inclusion of 2D Transition Metal Dichalcogenides in Perovskite Inks and Their Influence on Solar Cell Performance.

Organic-inorganic hybrid perovskite materials have raised great interest in recent years due to their excellent optoelectronic properties, which promise stunning improvements in photovoltaic technologies. Moreover, two-dimensional layered materials such as graphene, its derivatives, and transition metal dichalcogenides have been extensively investigated for a wide range of electronic and optoelectronic applications and have recently shown a synergistic effect in combination with hybrid perovskite materials. Here, we report on the inclusion of liquid-phase exfoliated molybdenum disulfide nanosheets into different perovskite precursor solutions, exploring their influence on final device performance. We compared the effect of such additives upon the growth of diverse perovskites, namely CH3NH3PbI3 (MAPbI3) and triple-cation with mixed halides Csx (MA0.17FA0.83)(1-x)Pb (I0.83Br0.17)3 perovskite. We show how for the referential MAPbI3 materials the addition of the MoS2 additive leads to the formation of larger, highly crystalline grains, which result in a remarkable 15% relative improvement in power conversion efficiency. On the other hand, for the mixed cation-halide perovskite no improvements were observed, confirming that the nucleation process for the two materials is differently influenced by the presence of MoS2.

Electrochromic evaluation of airbrushed water-dispersible W18O49nanorods obtained by microwave-assisted synthesis.

Motivated by the technological relevance of tungsten oxide nanostructures as valuable materials for energy saving technology, electrochemical and electrochromic characteristics of greener processed nanostructured W18O49-based electrodes are discussed in this work. For the purpose, microwave-assisted water-dispersible W18O49nanorods have been synthesized and processed into nanostructured electrodes. An airbrushing technique has been adopted as a cost-effective large-area scalable methodology to deposit the W18O49nanorods onto conductive glass. This approach preserves the morphological and crystallographic habit of native nanorods and allows highly homogeneous transparent coating where good electronic coupling between nanowires is ensured by a mild thermal treatment (250 °C, 30 min). Morphological and structural characteristics of active material were investigated from the synthesis to the nanocrystal deposition process by transmission and scanning electron microscopy, x-ray diffraction, atomic force microscopy and Raman spectroscopy. The as-obtained nanostructured film exhibited good reversible electrochemical features through several intercalation-deintercalation cycles. The electrochromic properties were evaluated on the basis of spectro-electrochemical measurements and showed significant optical contrast in the near-infrared region and high coloration efficiency at 550 nm.

Pseudocapacitive behaviour in sol-gel derived electrochromic titania nanostructures.

Nanostructured thin films are widely investigated for application in multifunctional devices thanks to their peculiar optoelectronic properties. In this work anatase TiO2 nanoparticles (average diameter 10 nm) synthesised by a green aqueous sol-gel route are exploited to fabricate optically active electrodes for pseudocapacitive-electrochromic devices. In our approach, highly transparent and homogeneous thin films having a good electronic coupling between nanoparticles are prepared. These electrodes present a spongy-like nanostructure in which the dimension of native nanoparticles is preserved, resulting in a huge surface area. Cyclic voltammetry studies reveal that there are significant contributions to the total stored charge from both intercalation capacitance and pseudocapacitance, with a remarkable 50% of the total charge deriving from this second effect. Fast and reversible colouration occurs, with an optical modulation of ∼60% in the range of 315-1660 nm, and a colouration efficiency of 25.1 cm2 C-1 at 550 nm. This combination of pseudocapacitance and electrochromism makes the sol-gel derived titania thin films promising candidates for multifunctional 'smart windows'.

Optimizing the Interface between Hole Transporting Material and Nanocomposite for Highly Efficient Perovskite Solar Cells.

The performances of organometallic halide perovskite-based solar cells severely depend on the device architecture and the interface between each layer included in the device stack. In particular, the interface between the charge transporting layer and the perovskite film is crucial, since it represents both the substrate where the perovskite polycrystalline film grows, thus directly influencing the active layer morphology, and an important site for electrical charge extraction and/or recombination. Here, we focus on engineering the interface between a perovskite-polymer nanocomposite, recently developed by our group, and different commonly employed polymeric hole transporters, namely PEDOT: PSS [poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)], PEDOT, PTAA [poly(bis 4-phenyl}{2,4,6-trimethylphenyl}amine)], Poly-TPD [Poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] Poly-TPD, in inverted planar perovskite solar cell architecture. The results show that when Poly-TPD is used as the hole transfer material, perovskite film morphology improved, suggesting an improvement in the interface between Poly-TPD and perovskite active layer. We additionally investigate the effect of the Molecular Weight (MW) of Poly-TPD on the performance of perovskite solar cells. By increasing the MW, the photovoltaic performances of the cells are enhanced, reaching power conversion efficiency as high as 16.3%.

An SPR based immunoassay for the sensitive detection of the soluble epithelial marker E-cadherin.

Protein biomarkers are important diagnostic tools for cancer and several other diseases. To be validated in a clinical context, a biomarker should satisfy some requirements including the ability to provide reliable information on a pathological state by measuring its expression levels. In parallel, the development of an approach capable of detecting biomarkers with high sensitivity and specificity would be ideally suited for clinical applications. Here, we performed an immune-based label free assay using Surface Plasmon Resonance (SPR)-based detection of the soluble form of E-cadherin, a cell-cell contact protein that is involved in the maintaining of tissue integrity. With this approach, we obtained a specific and quantitative detection of E-cadherin from a few hundred microliters of serum of breast cancer patients by obtaining a 10-fold enhancement in the detection limit over a traditional colorimetric ELISA.

Room-temperature processed films of colloidal carved rod-shaped nanocrystals of reduced tungsten oxide as interlayers for perovskite solar cells.

Thanks to their high stability, good optoelectronic and extraordinary electrochromic properties, tungsten oxides are among the most valuable yet underexploited materials for energy conversion applications. Herein, colloidal one-dimensional carved nanocrystals of reduced tungsten trioxide (WO3-x) are successfully integrated, for the first time, as a hole-transporting layer (HTL) into CH3NH3PbI3 perovskite solar cells with a planar inverted device architecture. Importantly, the use of such preformed nanocrystals guarantees the facile solution-cast-only deposition of a homogeneous WO3-x thin film at room temperature, allowing achievement of the highest power conversion efficiency ever reported for perovskite solar cells incorporating raw and un-doped tungsten oxide based HTL.

Polymeric Nano-Micelles as Novel Cargo-Carriers for LY2157299 Liver Cancer Cells Delivery.

LY2157299 (LY), which is very small molecule bringing high cancer diffusion, is a pathway antagonist against TGFß. LY dosage can be diluted by blood plasma, can be captured by immune system or it might be dissolved during digestion in gastrointestinal tract. The aim of our study is to optimize a "nano-elastic" carrier to avoid acidic pH of gastrointestinal tract, colon alkaline pH, and anti-immune recognition. Polygalacturonic acid (PgA) is not degradable in the gastrointestinal tract due to its insolubility at acidic pH. To avoid PgA solubility in the colon, we have designed its conjugation with Polyacrylic acid (PAA). PgA-PAA conjugation has enhanced their potential use for oral and injected dosage. Following these pre-requisites, novel polymeric nano-micelles derived from PgA-PAA conjugation and loading LY2157299 are developed and characterized. Efficacy, uptake and targeting against a hepatocellular carcinoma cell line (HLF) have also been demonstrated.

Hybrid polymeric-protein nano-carriers (HPPNC) for targeted delivery of TGFß inhibitors to hepatocellular carcinoma cells.

TGFß1 pathway antagonists have been considered promising therapies to attenuate TGFß downstream signals in cancer cells. Inhibiting peptides, as P-17 in this study, are bound to either TGFß1 or its receptors, blocking signal transduction. However, for efficient use of these TGFß1antagonist as target therapeutic tools, improvement in their delivery is required. Here, a plasmid carrying specific shDNA (SHT-DNA), small interfering RNA (siRNA), and the peptide (P-17) were loaded separately into folic acid (FA)-functionalized nano-carriers made of Bovine Serum Albumin (BSA). The two building blocks of the carrier, (BSA and FA) were used because of the high affinity of albumin for liver and for the overexpression of folate receptors on the membrane of hepatocellular carcinoma cells. The empty and the encapsulated carriers were thoroughly investigated to characterize their structure, to evaluate the colloidal stability and the surface functionalization. The entrapment of SHT-DNA, siRNA and P-17, respectively, was demonstrated by morphological and quantitative analysis. Finally, cellular studies were performed to assess the targeting efficiency of the hybrid carriers. These vectors were used because of the high affinity of albumin for liver and for the overexpression of folate receptors on the membrane hepatocellular carcinoma cells. The empty and the encapsulated carriers were thoroughly investigated to characterize their structure, to evaluate the colloidal stability and the surface functionalization. The entrapment of SHT-DNA, siRNA and P-17, respectively, was demonstrated by morphological and quantitative analysis. A novel fabrication of Hybrid Polymeric-Protein Nano-Carriers (HPPNC) for delivering TGF ß1 inhibitors to HCC cells has been developed. SHT-DNA, siRNA and P-17 have been successfully encapsulated. TGF ß1 inhibitors-loaded HPPNC were efficiently uptaken by HLF cells.

Smart windows for building integration: a new architecture for photovoltachromic devices.

A new architecture for multifunctional photoelectrochemical devices, namely photovoltachromic devices, is disclosed here, capable of producing electric energy by solar conversion also modulating the devices' optical transmittance in a smart and aesthetically sounding fashion. These devices generally consist of a titanium dioxide photoelectrode and of a bifunctional patterned counter electrode made of platinum and amorphous tungsten oxide. The innovative configuration described hereafter proposes to split the single patterned counter electrode into two distinct electrodes, physically overlapped: the central one is suitably drilled in order to allow the electrolyte to fill both communicating chambers. These three electrode devices allow three independent operating modes: photovoltaic, photoelectrochromic, and photovoltachromic. In this paper, we report the optical, electrical, and electrochemical characterization of this innovative device, varying both available catalytic surface area and the type of sensitizing dye. We eventually obtained the following conversion efficiencies, 2.75%, 2.35%, and 1.91%, in samples having different catalytic areas (397, 360, and 320 mm(2), respectively). We inferred that the higher the platinum area on the interposed platinum-poly(ethylene naphthalate)-indium tin oxide counter electrode, the higher the photovoltaic conversion efficiency. On the other hand, a decrease of the intercommunication openings generates a slowdown of bleaching processes.

Photovoltachromic device with a micropatterned bifunctional counter electrode.

A photovoltachromic window can potentially act as a smart glass skin which generates electric energy as a common dye-sensitized solar cell and, at the same time, control the incoming energy flux by reacting to even small modifications in the solar radiation intensity. We report here the successful implementation of a novel architecture of a photovoltachromic cell based on an engineered bifunctional counter electrode consisting of two physically separated platinum and tungsten oxide regions, which are arranged to form complementary comb-like patterns. Solar light is partially harvested by a dye-sensitized photoelectrode made on the front glass of the cell which fully overlaps a bifunctional counter electrode made on the back glass. When the cell is illuminated, the photovoltage drives electrons into the electrochromic stripes through the photoelectrochromic circuit and promotes the Li(+) diffusion towards the WO3 film, which thus turns into its colored state: a photocoloration efficiency of 17 cm(2) min(-1) W(-1) at a wavelength of 650 nm under 1.0 sun was reported along with fast response (coloration time <2 s and bleaching time <5 s). A fairly efficient photovoltaic functionality was also retained due to the copresence of the independently switchable micropatterned platinum electrode.

A colour tunable microcavity by weak-to-strong coupling regime transition through a light-switchable material.

An organic based microcavity showing fully reversible colour tunability has been achieved for the first time. The emission output changes according to the modulation from pure photonic to polaritonic resonant modes through UV irradiation of the light-switchable matrix.

Aryl 5-substitution of a phenyl-pyridine based ligand as a viable way to influence the opto-electronic properties of bis-cyclometalated Ir(III) heteroleptic complexes.

This manuscript reports on the synthesis, the photophysical study and the electroluminescent properties of a series of heteroleptic cyclometalated iridium(III) complexes based on 2,5-diaryl-pyridines as C^N cyclometalating ligands and acetylacetonate as ancillary ligand. The complexes were characterised by elemental analysis, ESI-MS, multinuclear NMR, TGA and electrochemistry. Their optical properties were investigated by UV-Vis and photoluminescence. DFT and TD-DFT calculations provided further insights into the effects of the 5-aryl substitution on the electronic and photophysical properties of the new complexes. The presence of suitable π-extended ligands exerts a beneficial effect on the performances of the corresponding solution-processed light-emitting diodes, leading to a maximum brightness of 10,620 cd m(-2) at a current efficiency of 10.0 cd A(-1).

Monodispersed molecular donors for bulk hetero-junction solar cells: from molecular properties to device performances.

The relations between the chemical-physical properties of novel designed monodispersed donors and their photovoltaic performances are discussed. The importance of intermolecular interactions is emphasized to figure out the achievement of high performing bulk hetero-junction solar cells which are solution processed.

Pure white hybrid light-emitting device with color rendering index higher than 90.

The realization of white-light sources with a combination of high color rendering index (CRI), which is the average of the first eight rendering indices, and the deep-red color rendering R9 is an important challenge in the field of solid-state lighting. Herein, we report on a pure white hybrid light-emitting device combining a deep-blue emission from a polymer with blue, green, and red emissions from ternary CdSe/ZnS quantum dots. By carefully designing the device structure and tuning the ratio of QDs with different sizes, high CRI of 94 and R9 of 92 at 525 cd/m(2) were achieved.