An integrated bulk and surface modification strategy for gas-quenched inverted perovskite solar cells with efficiencies exceeding 22%

Inverted perovskite solar cells (PSCs) prepared by anti-solvent method have achieved power conversion efficiencies (PCEs) of over 23%, but they are not ideal for device upscaling. Conversely, gas-quenched PSCs offer great potential for upscaling, but their performance still lags behind. Herein, we seek to upgrade the gas-quenched films through both surface and bulk modifications. First, a novel surface modifier, benzylammonium thiocyanate (BASCN), is found to allow remarkably improved surface properties, but the PCE gain is limited by the existence of longitudinally multiple grains. Thus, we further utilize methylammonium chloride (MACl) additive as a second modifier to realize monolithic grains. Such an integrated strategy enables the average open-circuit voltage (V_oc) of the gas-quenched PSCs to increase from 1.08 V to 1.15 V, leading to a champion PCE of 22.3%. Moreover, the unencapsulated device shows negligible degradation after 150 h of maximum power point operation under simulated 1 sun illumination in N₂.