A Universal Grain “Cage” to Suppress Halide Segregation of Mixed-Halide Inorganic Perovskite Solar Cells

Abstract

Bandgap-tunable mixed-halide perovskites offer exciting opportunities to construct efficient multijunction tandem solar cells. However, the ion migration always causes halide segregation, which inevitably creates detrimental defects and deteriorates the photovoltaic performances. Here, we report a universal caging strategy to suppress halide segregation by in situ formation of conjugated covalent organic frameworks (COFs) catalyzed by PbX2 (X = Br and I) during the formation of mixed-halide perovskite. Through theoretical calculation and systematic investigation, the strong electron-donating feature of COFs is shown to effectively solidify the soft lattice and impede the iodide ion transport from bulk to grain boundary, decelerating the light-induced halide-demixing process. Finally, the nonradiative recombination is significantly reduced, boosting efficiency up to 11.50% for an inorganic CsPbIBr2 perovskite solar cell and 14.35% for a CsPbI2Br cell with a prolonged shelf life and an improved photostability.

Targeting the imperfections at the ZnO/CsPbI2Br interface for low-temperature carbon-based perovskite solar cells

“…1,2 At present, most state-of-the-art C-IPSCs are composed of a titanium dioxide (TiO 2 ) electron transport layer (ETL). 11 However, the growth of TiO 2 generally requires a high annealing temperature ($450 °C) and a complicated fabrication process, which are both energy-consuming and incompatible with exible devices. 12 Meanwhile, the lower electron mobility (m e ) and excellent photocatalytic activity of TiO 2 will cause unbalanced charge transport and thus adversely affect device stability.…”

Pure‐Iodide Wide‐Bandgap Perovskites for High‐Efficiency Solar Cells by Crystallization Control

“…The improved perovskite film was verified by the hole transport layer (HTL)-free carbon electrode-based PSCs (C-PSCs), which are devices with a simplified structure avoiding the use of expensive HTL and metal electrode, thereby possessing the advantage of low cost. [36][37][38][39][40][41][42][43][44][45][46] Benefiting from the optimal MDACl 2 modification, the efficiency of the FA 0.5 Cs 0.5 PbI 3 C-PSCs was improved from 16.72% to 18.52%. To our knowledge, this PCE delivers one of the highest levels in the field of HTL-free C-PSCs, even based on wide-bandgap perovskite.…”

Dual Interface Passivation in Mixed-Halide Perovskite Solar Cells by Bilateral Amine

“…Aside from that, the majority of passivation materials are deposited on top of a perovskite thin film with no strong bonding or chemical interaction between the perovskite and passivator . The passivation of perovskite interfaces at both ETL and HTL without introducing an intermediate quasi-2D phase can significantly improve the nonradiative recombination and photovoltage. ,,, However, the way to overcome these limitations while fabricating the perovskite solar cells is still unclear and the predicted V OC is not achieved yet.…”

“…37 The passivation of perovskite interfaces at both ETL and HTL without introducing an intermediate quasi-2D phase can significantly improve the nonradiative recombination and photovoltage. 29,31,32,38 However, the way to overcome these limitations while fabricating the perovskite solar cells is still unclear and the predicted V OC is not achieved yet.…”