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Perovskite silicon tandem solar cells are one of the effective ways to further improve the photoelectric conversion efficiency (PCE) in the research and development of solar cells in the future. CsPbIBr2 can be used as the top cell material in tandem solar cells due to its wider bandgap and better long‐term stability. However, the serious defect density and carrier recombination limit its further improvement. In this work, Octylammonium Octyldithiocarbamate (ODTC) is added to the CsPbIBr2 precursor. Through its strong metal ion complexing ability, it combines with the uncoordinated Pb2+ in the CsPbIBr2, and then thermally decomposes to produce PbS during the annealing process. As an additive, ODTC modulates the crystallization of CsPbIBr2, increases the crystal size, reduces defect density, extends carrier lifetime, and improves charge transfer. Moreover, in situ‐generated PbS can also optimize photovoltaic performance of CsPbIBr2 perovskite solar cell (PSC). Consequently, the champion PCE of the devices can attain to 10.15% and still maintain an initial efficiency of 90% after 45 days. Therefore, the strategy is an effective way to prepare efficient and stable CsPbIBr2 PSCs. [ABSTRACT FROM AUTHOR]

Stability has always been a major challenge in the commercialization of perovskite solar cells (PSCs). All‐inorganic perovskite semiconductor materials have attracted much attention in the field and are considered to be the best choice to solve this challenge due to their good thermal stability. However, all‐inorganic perovskite films contain a high density of defects that provide channels for nonradiative recombination of charges and ion transport, which seriously threaten the stability of PSCs. Different defects have corresponding passivation mechanisms. Through the introduction of multifunctional additives, multiple passivation effects can be realized at the same time, and the power conversion efficiency (PCE) can be greatly improved. Herein, the introduction of the small biological molecule (adenosine) as the additive into the perovskite precursor can maximize the passivation mechanisms of Lewis bases. The doping of adenosine improves the crystallinity, reduces the density of trap states and enhances the light absorption, and finally obtains PSCs with the best PCE of 10.24%, which is 30.8% higher than that of the standard device. In addition, adenine is also introduced as a comparative study, and the treated CsPbIBr2 PSC with a PCE of 9.72% is finally obtained. [ABSTRACT FROM AUTHOR]

Favorable stability is a big challenge for the commercialization of perovskite solar cells, and all‐inorganic perovskite semiconductors have attracted much attention due to their excellent performance in this field. In reality, the poor stability is mainly due to the high‐density defects in the perovskite films, which provide a channel for charge nonradiative recombination and ion migration. In this work, a multifunctional aminoguanidine hemisulfate (AG HSUL) is introduced into the CsPbIBr2 perovskite layer to achieve defect passivation. Guanidine cations (GA+) can form strong hydrogen bonds with under‐coordinated halogen ions to stabilize the crystal lattice; the nitrogen atom in the amino group can form a complex with the under‐coordinated lead ion; inorganic acids and ions can not only compensate for halogen anion vacancies, but also combine with lead clusters or capped lead ions to reduce defect density. The synergistic effect of anions and cations can effectively passivate the defects, and an energy conversion efficiency of 10.10% is obtained at the optimal concentration of modification. In addition, carbon electrodes are used instead of metal electrodes, which greatly reduces the cost. The results provide a new idea for the development of efficient all‐inorganic CsPbIBr2 perovskite solar cells. [ABSTRACT FROM AUTHOR]

Inorganic cesium lead halide perovskite solar cells have attracted widespread attention owing to their excellent stability relative to organic–inorganic solar cells. However, all‐inorganic perovskite solar cells without hole transport layers and using carbon layers as electrodes have serious energy level mismatch problems. To overcome this problem, here, the CsPbIBr2 surface is treated with 4‐aminomethyltetrahydropyran acetate to form a gradient energy band on the CsPbIBr2 perovskite/carbon interface. As a result, the hole extraction efficiency is successfully improved, and the morphology and crystallization of the perovskite layer are also improved. Moreover, the nonradiative recombination inside the perovskite and the charge recombination at the interface are effectively inhibited. Therefore, the power conversion efficiency of CsPbIBr2 solar cell is enhanced to 10.12%, and the high photovoltage of 1.32 V is obtained under one solar illumination, which are both higher than the pristine one (7.79%, 1.23V, respectively). [ABSTRACT FROM AUTHOR]

High‐quality and low‐defect perovskite active layer (PVK) and electron transport layer (ETL) are essential for high‐performance perovskite solar cells (PSCs). Herein, an alkylamine salt, cyclohexylmethylammonium chloride (CMACl) is introduced into tin oxide (SnO2) ETL. CMACl, possessing protonated −NH3+ group and Cl− ions, not only effectively inhibits the aggregation of SnO2 colloids and enhances the quality of the ETLs, but also reduces and passivates the defects on ETLs. On the other hand, via the across‐interface effect of alkylamine salt by thermal diffusion, the CMACl‐PbI2 intermediate phase is formed and leads to the high quality of PVK, meanwhile, the defect on the buried interfaces and in the bulk of PVK are passivated by CMA+ and Cl− ions. Consequently, the CMACl‐modified PSC achieves a preeminent power conversion efficiency of 25.47% and excellent stability. This work demonstrates a facile and effective approach for synchronous optimization of ETL and PVK for high‐performance PSCs by across‐interface effect. [ABSTRACT FROM AUTHOR]

In recent years, carbon-based CsPbI 2 Br perovskite solar cells (PSCs) have attracted more attention due to their low cost and good stability. However, the power conversion efficiency (PCE) of carbon-based CsPbI 2 Br PSCs is still no more than 16%, because of the defects in CsPbI 2 Br or at the interface with the electron transport layer (ETL), as well as the energy level mismatch, which lead to the loss of energy, thus limiting PCE values. Herein, a series of cadmium halides are introduced, including CdCl 2 , CdBr 2 and CdI 2 for dual direction thermal diffusion treatment. Some Cd 2+ ions thermally diffuse downward to passivate the defects inside or on the surface of SnO 2 ETL. Meanwhile, the energy level structure of SnO 2 ETL is adjusted, which is in favor of the transfer of electron carriers and blocking holes. On the other hand, part of Cd 2+ and Cl - ions thermally diffuse upward into the CsPbI 2 Br lattice to passivate crystal defects. Through dual direction thermal diffusion treatment by CdCl 2 , CdI 2 and CdBr 2 , the performance of devices has been significantly improved, and their PCE has been increased from 13.01% of the original device to 14.47%, 14.31%, and 13.46%, respectively. According to existing reports, 14.47% is one of the highest PCE of carbon-based CsPbI 2 Br PSCs with SnO 2 ETLs., (© 2022 Wiley-VCH GmbH.)

A catalytic enantioselective formal [2+2] cycloaddition between α-halo acroleins and electronically diverse arylalkenes is described. In the presence of (S)-oxazaborolidinium cation as the catalyst, densely functionalized cyclobutanes containing two vicinal tetrasubstituted stereocenters were produced in high yields and high diastereoselectivities with excellent enantioselectivities. Mechanistic studies revealed that the cis isomer could be transformed into the trans isomer via an enantiocontrolled process. A gram-scale reaction of this catalytic method was used to demonstrate its synthetic potential., (© 2020 Wiley-VCH GmbH.)