The commercialization of perovskite solar cells (PSCs) has seen an important limitation in the instability that afflicts the hole-transporting layer (HTL), namely, spiro-OMeTAD, used in high-efficiency devices. The latter is, in turn, relatively expensive, undermining the sustainability of the device. Its replacement with polymeric scaffolds, such as poly(3-hexylthiophene) (P3HT), will solve these issues. In this work, we adopted various sustainable synthetic methods to obtain four different homemade P3HTs with different molecular weights (MWs) and regioregularities (RRs), leading to different structural properties. They are implemented as HTLs in PSCs, and the effect of their properties on the efficiency and thermal stability of devices is thoroughly discussed. The highest efficiency is obtained with the highest MW and low-RR polymer (17.6%) owing to the more sustainable approach, but a very promising value is also reached with a lower-MW but fully regioregular polymer (15%). Finally, large-area devices with an efficiency of 16.7%, fabricated with a high-MW P3HT, show more than 1000 h (T80 = 1108 h) of stability under accelerated thermal stress tests (85 °C) out of glovebox while keeping over 85% of the initial efficiency of an unencapsulated device after more than 3000 min under continuous light soaking (AM 1.5G).

This review presents studies devoted to the description and comprehension of phenomena connected with the sensing behaviour towards NO₂ of films of two phthalocyanines, titanium bis-phthalocyanine and ruthenium phthalocyanine. Spectroscopic, conductometric, and morphological features recorded during exposure to the gas are explained and the mechanisms of gas-molecule interaction are also elucidated. The review also shows how X-ray reflectivity can be a useful tool for monitoring morphological parameters such as thickness and roughness that are demonstrated to be sensitive variables for monitoring the exposure of thin films of sensor materials to NO₂ gas.

Efficient semi‐transparent solar cells can extend the adoption of photovoltaics beyond standard utility‐scale, commercial, or residential applications. Halide perovskites are particularly suitable in this respect owing to their tunable bandgap. The main drawbacks in the development of transparent perovskite solar cells are the high open‐circuit voltage (V_oc) deficit and the difficulties in depositing high‐quality thin films over large area substrates, given the low solubility of bromide and chloride precursors. In this work, passivation strategies are developed for the high bandgap Br perovskite able to reduce charge recombination and consequently improve the V_oc. The study demonstrates 1 cm² perovskite solar cells with V_oc up to 1.73 V (1.83 eV Quasi Fermi Level Splitting) and a PCE of 8.1%. The average visible transmittance (AVT) exceeds 70% by means of a bifacial light management and a record light utilization efficiency (LUE) of 5.72 is achieved. Moreover, the potential use of the technology is evaluated toward Internet of Things (IoT) application owing to a bifaciality factor of 87% along with 17% PCE under indoor lighting. Finally, the up‐scaling is demonstrated by fabricating 20 cm² active area modules with PCE of 7.3% and V_oc per cell up to 1.65 V.

CsPbBr₃ and Cs₄PbBr₆ perovskite powders have been synthesized through a relatively simple low-temperature and low-cost method. Nanocrystalline films have also been deposited from solutions with four different molar compositions of binary salt precursors. Optical absorption, emission and excitation spectra have been performed in the UV-visible spectral range while X-ray diffraction (XRD) has been recorded to characterize the nanocrystal morphology for the different molar compositions. A preferential orientation of crystallites along the (024) crystalline plane has been observed as a function of the different deposition conditions in films growth. All the crystals show an absorption edge around 530 nm; Tauc plots of the absorption returned bandgaps ranging from 2.29 to 2.35 eV characteristic of CsPbBr₃ phase. We attribute the UV absorption band peaked at 324 nm to the fundamental band-to-band transition for Cs₄PbBr₆. It was observed that the samples with the most ordered Cs₄PbBr₆ crystals exhibited the most intense emission of light, with a bright green emission at 520 nm, which are however due to the luminescence of the inclusion of CsPbBr₃ nanoclusters into the Cs₄PbBr₆. The latter shows instead an intense UV emission. Differently, the pure CsPbBr₃ powder did not show any intense fluorescent emission. The excitation spectra of the green fluorescent emission in all samples closely resemble the CsPbBr₃ absorption with the peculiar dip around 324 nm as expected from density of state calculations reported in the literature.