For the past decade, lead halide perovskites have experienced impressive progress in photovoltaics with the certified device conversion efficiency over 25%, owing to their outstanding optoelectronic properties. However, the toxicity...

Spiro-OMeTAD is the most-employed molecular hole-transporting material (HTM) in n-i-p perovskite solar cells (PSCs). Ease of processing from solution and good filmability on top of the perovskite photo-active layer are characteristics that make this HTM outstanding and incomparable for the role. However, chemical doping with both tert-butylpyridine (tBP) and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), coupled with further oxidation steps, is required in order to achieve high hole mobility and conductivity. Previous investigations have revealed that tBP is fundamental for addressing the best morphology in the hole-transporting layer during processing. Here, we provide spectroscopic evidence of the detrimental impact on long-term conservation of Spiro-OMeTAD structural and electrical properties when tBP is used as an additive. These aspects are crucial for the future design and understanding of new molecular HTMs for PSCs.

Metal halide perovskite materials have opened up a great opportunity for high-performance optoelectronic devices owing to their extraordinary optoelectronic properties. More than lead halide ones, stable and nontoxic bismuth halide perovskites exhibit more promise in their future commercialization. In this work, we developed for the first time photodetectors based on full-inorganic Cs 3 Bi 2 I 9−x Br x perovskites and modulate their performance by varying x in the composition systematically. Among those self-powered photodetectors, those based on Cs 3 Bi 2 I 6 Br 3 shows the best performance with excellent photosensitivity of 4.1 × 10 4 at zero bias as well as the responsivity and detectivity reaching 15 mA/W and 4.6 × 10 11 Jones, respectively. More strikingly, the full-inorganic perovskite photodetectors exhibit excellent stability in the ambient environment and can maintain over 96% of the initial value after 100 days owing to the high stability of the core perovskite film. The paper definitely paves an alternative and promising strategy for the design of future commercial photodetectors that are self-powered, stable, nontoxic, etc.

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Perovskite solar cells (PSCs) are demonstrating great potential to compete with second generation photovoltaics. Nevertheless, the key issue hindering PSCs full exploitation relies on their stability. Among the strategies devised to overcome this problem, the use of carbon nanostructures (CNSs) as hole transporting materials (HTMs) has given impressive results in terms of solar cells stability to moisture, air oxygen, and heat. Here, the use of a HTM based on a poly(3‐hexylthiophene) (P3HT) matrix doped with organic functionalized single walled carbon nanotubes (SWCNTs) and reduced graphene oxide in PSCs is proposed to achieve higher power conversion efficiencies (η = 11% and 7.3%, respectively) and prolonged shelf‐life stabilities (480 h) in comparison with a benchmark PSC fabricated with a bare P3HT HTM (η = 4.3% at 480 h). Further endurance test, i.e., up to 3240 h, has shown the failure of all the PSCs based on undoped P3HT, while, on the contrary, a η of ≈8.7% is still detected from devices containing 2 wt% SWCNT‐doped P3HT as HTM. The increase in photovoltaic performances and stabilities of the P3HT‐CNS‐based solar cell, with respect to the standard P3HT‐based one, is attributed to the improved interfacial contacts between the doped HTM and the adjacent layers.

As the most promising lead‐free branch, tin halide perovskites suffer from the severe oxidation from Sn2+ to Sn4+, which results in the unsatisfactory conversion efficiency far from what they deserve. In this work, by facile incorporation of methylammonium bromide in composition engineering, formamidinium and methylammonium mixed cations tin halide perovskite films with ultrahighly oriented crystallization are synthesized with the preferential facet of (001), and that oxidation is suppressed with obviously declined trap density. MA+ ions are responsible for that impressive orientation while Br‐ ions account for their bandgap modulation. Depending on high quality of the optimal MA0.25FA0.75SnI2.75Br0.25 perovskite films, their device conversion efficiency surges to 9.31% in contrast to 5.02% of the control formamidinium tin triiodide perovskite (FASnI3) device, along with almost eliminated hysteresis. That also results in the outstanding device stability, maintaining above 80% of the initial efficiency after 300 h of light soaking while the control FASnI3 device fails within 120 h. This paper definitely paves a facile and effective way to develop high‐efficiency tin halide perovskites solar cells, optoelectronic devices, and beyond.

Double perovskites are promising candidates for less toxic and highly stable metal halide perovskites, but their optoelectronic performances still lag behind those of the lead halide counterpart, due to the indirect nature of the bandgap and the strong electron–phonon coupling. Reducing the dimensionality of Cs2AgBiBr6 down to a 2D layered form is strategic in order to tune the band gap from indirect to direct and provides new insights into the structure–property relationships of double perovskites. Herein, we report on a series of monolayer 2D hybrid double perovskites of formula (RA)4AgBiBr8, where RA represents different primary ammonium large cations with alkyl- and aryl-based functionalities. An in-depth experimental characterization of structure, film morphology, and optical properties of these perovskites is carried out. Interestingly, the variation of the ammonium cation and the interplanar distance between adjacent inorganic monolayers has peculiar effects on the film-forming ability and light emission properties of the perovskites. Experiments have been combined with DFT calculations in order to understand the possible origin of the different emissive features. Our study provides a toolbox for future rational developments of 2D double perovskites, with the aim of narrowing the gap with lead halide perovskite optoelectronic properties.

Carbon nanostructures (CNSs), which are made up of extended sp2-hybridized carbon networks, are largely employed as nanofillers for polymer phases to obtain polymerbased nanocomposites (PNCs). Following their inclusion, the polymer matrices are often improved in many ways, such as enhanced electrical and thermal conductivity, increased stability, and mechanical robustness. The chemical functionalization of the external CNS surfaces with organic substituents is often a key tool for their effective and homogeneous incorporation within a polymer phase, avoiding the formation of aggregates, which can lower the performance of the the final material. This microreview furnishes an overview of PNCs that contain substituted CNSs with organic functionalities. These CNS-based PNCs can be used as organic functional materials in different applications that range from clean energy harvesting and storage to sensing and biomedicine