Achieving >23% Efficiency Perovskite Solar Minimodules with Surface Conductive Coordination Polymer

Abstract Despite the reported high efficiencies of small‐area perovskite photovoltaic cells, the deficiency in large‐area modules has impeded the commercialization of perovskite photovoltaics. Enhancing the surface/interface conductivity and carrier‐transport in polycrystalline perovskite films presents significant potential for boosting the efficiency of perovskite solar modules (PSMs) by mitigating voltage losses. This is particularly critical for multi‐series connected sub‐cell modules, where device resistance significantly impacts performance compared to small‐area cells. Here, an effective approach is reported for decreasing photovoltage loss through surface/interface modulation of perovskite film with a surface conductive coordination polymer. With post‐treatment of meso‐tetra pyridine porphyrin on perovskite film, PbI 2 on perovskite film reacts with pyridine units in porphyrins to generate an iso‐structural 2D coordination polymer with a layered surface conductivity as high as 1.14 × 10 2 S m −1 , due to the effect of surface structure reconstruction. Modified perovskite film exhibits greatly increased surface/interface conductivity. The champion PSM obtains a record efficiency up to 23.39% (certified 22.63% with an aperture area of 11.42 cm 2 ) featuring only 0.33‐volt voltage loss. Such a modification also leads to substantially improved operational device stability.