Halide perovskite solar cells (PSCs) have shown outstanding performance, which can be further improved through enhancing the built-in electric field (V_bi) and reducing non-radiative recombination pathways. Here we in-situ grow an organic-inorganic ferroelectric layer on the perovskite film, which can be easily and quickly processed even at room-temperature within one minute. The in-situ process endows intimate growth of ferroelectric layer on the original perovskite grains, which can reduce the formation of grain boundaries and thus minimize the recombination of electron and hole at grain boundaries. The V_bi of the PSCs is enhanced from 1.02 V to 1.28 V due to the widened space charge depletion region after the formation of ferroelectric layer. Finally, an output photovoltage up to 1198 mV is achieved with a champion efficiency of 22.45% and a low voltage deficit of 352 mV. The strategy offers a new platform of growing intimate ferroelectric layers on perovskite photoactive films for integration between ferroelectrics and PSCs.

卤化物钙钛矿太阳能电池 (PSC) 表现出出色的性能，可以通过增强内建电场 ( V _bi ) 和减少非辐射复合途径进一步提高性能。在这里，我们在钙钛矿薄膜上原位生长有机-无机铁电层，即使在室温下也可以在一分钟内轻松快速地进行处理。原位工艺赋予原始钙钛矿晶粒上铁电层的紧密生长，可以减少晶界的形成，从而最大限度地减少电子和空穴在晶界处的复合。V_双_由于铁电层形成后空间电荷耗尽区变宽，PSC 的电压从 1.02 V 提高到 1.28 V。最后，以 22.45% 的冠军效率和 352 mV 的低压差实现了高达 1198 mV 的输出光电压。该策略提供了一个在钙钛矿光敏薄膜上生长紧密铁电层的新平台，用于铁电体和 PSC 之间的集成。