As an inorganic halide perovskite (IHP), CsPbI2Br has generated enormous publicity due to its suitable optical bandgap (≈1.92 eV) and thermal stability. Unfortunately, the terrible phase stability of CsPbI2Br film will cause a phase change in a wet environment and decelerate light response, seriously hindering the progression of IHP photovoltaics. Herein, a synergistic postmodification strategy with CsBr and MABr to achieve high‐quality CsPbI2Br film at a low‐temperature (≈150 °C) and positive perovskite/carbon interface is presented. Adding a small amount of MABr can promote the crystallization of perovskite. The evaporated CsBr accumulates on the grain boundaries and surface of CsPbI2Br and forms Br‐rich perovskite, which provides the protection of CsPbI2Br and segregation of water vapor. The carbon‐based perovskite solar cell (C‐PeSC) with the modified CsPbI2Br harvests a high power conversion efficiency (PCE) of 11.04%. Notably, the unpackaged cell maintains 81% of its original PCE after being stored for 21 days in an air atmosphere with 25–35% humidity. Flexible devices are further manufactured, whose PCE drops to 90% of the initial value during 150 bending cycles. The flexible device also exhibits excellent blue photodetection performances. The maximum responsivity and detection reach 0.68 A W−1 and 8.91 × 1012 Jones, respectively. These findings provide broader avenues for flexible IHP in multifunctional devices.
As an inorganic halide perovskite (IHP), CsPbI2Br has generated enormous publicity due to its suitable optical bandgap (≈1.92 eV) and thermal stability. Unfortunately, the terrible phase stability of CsPbI2Br film will cause a phase change in a wet environment and decelerate light response, seriously hindering the progression of IHP photovoltaics. Herein, a synergistic postmodification strategy with CsBr and MABr to achieve high‐quality CsPbI2Br film at a low‐temperature (≈150 °C) and positive perovskite/carbon interface is presented. Adding a small amount of MABr can promote the crystallization of perovskite. The evaporated CsBr accumulates on the grain boundaries and surface of CsPbI2Br and forms Br‐rich perovskite, which provides the protection of CsPbI2Br and segregation of water vapor. The carbon‐based perovskite solar cell (C‐PeSC) with the modified CsPbI2Br harvests a high power conversion efficiency (PCE) of 11.04%. Notably, the unpackaged cell maintains 81% of its original PCE after being stored for 21 days in an air atmosphere with 25–35% humidity. Flexible devices are further manufactured, whose PCE drops to 90% of the initial value during 150 bending cycles. The flexible device also exhibits excellent blue photodetection performances. The maximum responsivity and detection reach 0.68 A W−1 and 8.91 × 1012 Jones, respectively. These findings provide broader avenues for flexible IHP in multifunctional devices.
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