Search

Perovskite solar cells (PSCs) based on formamidinium lead iodide (FAPbI3) have demonstrated the highest power conversion efficiencies. Typically fabricated through solution‐processing, FAPbI3 films necessitate intricate crystallization control to avoid the formation of a more stable non‐perovskite phase. Magnetron sputtering, an effective solvent‐free technique, has gained attention for producing large‐area perovskite films. Here, a novel approach to create high‐quality FAPbI3‐based perovskite thin films by employing magnetron sputtering is presented. Specifically, a mechanosynthesized blend of (FA1‐xMAx)Pb(I1‐xBrx)3 (MA = methylammonium) is used as a single‐source target for sputtering, and a post‐annealing transforms various phases in the initial deposited film into coherent FAPbI3‐based films with an ultra‐long and controlled crystallization process. Despite minimal residual MABr after post‐annealing, its presence is crucial in the formation of perovskite film, as evidenced by a distinct solid‐state phase transformation process is presented. A comprehensive investigation of the films' structural, compositional, and optical properties, with respect to varying MABr doping ratios, reveals details of perovskite phase development and the pivotal influence of MABr. PSCs fabricated with the optimized films display a substantial increase in the power conversion efficiency, reaching 20.1%. These results underscore the potential of combining magnetron sputtering and post‐annealing in the scalable production of high‐efficiency PSCs. [ABSTRACT FROM AUTHOR]

The last decade has witnessed a rapid growth of perovskite solar cells extended from mesoporous to planar architecture as well as from solution processing to solvent-free fabrication. The preparation of perovskite films by solvent-free method still presents significant challenges, such as the difficulty of film preparation by multiple evaporation sources in vapor deposition and the immaturity of the sputtered method. Here, we present a planar perovskite solar cell fabricated by solvent-free magnetron sputtering without the assistance of the mesoporous TiO 2 layer, and lead chloride (PbCl 2 ) was mechanically milled into the target of methylammonium lead halides (MAPbI 3 ) to improve the quality of perovskite film by regulating the crystallization process with the Cl element. Furthermore, the internal reason for the effect of different PbCl 2 doping contents on the trap density of perovskite films was also investigated in detail. These lead to an improved power conversion efficiency of planar heterojunction perovskite solar cells up to 17.10%, which is the highest efficiency recorded for the sputtered perovskite solar cells so far. The stability of resulting solar cells has also been significantly improved by exploring the doping mechanism of perovskite films with PbCl 2 in detail, showing great research and application prospect.

Organic-inorganic hybrid perovskites have emerged as promising light harvesting materials for many optoelectronic devices. Here, we present a facile mechanochemical synthesis (MCS) route for the preparation of a series of pure phase mixed-cation/anion (FAPbI 3 ) x (MAPbBr 3 ) 1- x (0 ≤ x ≤ 1) hybrid perovskite materials for high-efficiency thin-film perovskite solar cells (PSCs). The use of (α-FAPbI 3 ) 0.95 (MAPbBr 3 ) 0.05 perovskite prepared by MCS for the thin-film PSCs achieves a maximum PCE of 15.9% from a current-voltage ( J - V ) scan, which stabilises at 15.4% after 120 s of the maximum power point output. Furthermore, PSCs based on (KPbI 3 ) 0.05 (FAPbI 3 ) 0.9 (MAPbBr 3 ) 0.05 perovskite prepared by MCS exhibit higher photovoltaic performance and lower hysteresis compared with (α-FAPbI 3 ) 0.95 (MAPbBr 3 ) 0.05 , with a maximum PCE of 16.7%. These results indicate that the use of mechanochemically synthesised perovskites provides a promising strategy for high performance PSCs and superior control in optoelectronic properties, leading to improved control in fabrication approaches and facilitating the development of efficient and stable PSCs in the future., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Hybrid perovskites have recently received much attention in optoelectronic applications. However, hybrid perovskites are unstable in a humid environment. Mixed halide perovskites (MHPs) show enhanced stability and band-gap tunability upon engineering of their halide composition. Here, MHPs are prepared through a solvent-free mechanochemical synthesis (MCS) route that allows superior control over halide compositions than the solvent synthesis routes (SS). The MCS route eliminates the problem in the preparation of MAPb(I x Br 1-x ) 3 with continuously varying x, while maintaining the material properties and suppressing phase segregation present in SS routes. UV-vis absorption and X-ray diffraction patterns confirm the production of the desired pure-phase MHPs. For MAPb(I x Br 1-x ) 3 (0≤x≤1), with increased ratio of halide (x), the cubic phase gradually transforms into the tetragonal phase and band-gap tunability is accomplished. The MCS route for the preparation of MHPs is a very promising and efficient technique for superior control in optoelectronic properties, leading to improved control in fabrication approaches., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)