Local phase-modulated heterostructures for perovskite solar cells with high-efficiency and ultra-stability

Abstract

Simultaneous effective defect passivation and excellent charge extraction can maximize the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Unlike previously established heterojunction-based PSCs, we herein introduce a brand-new local phase-modulated heterostructure capable of exerting the aforementioned effects on PSCs, in which we incorporate a substantial quantity of a newly developed organic semiconductor (CY molecules) into the entire perovskite lattices, as well as on the surface and at grain boundaries. A promising PCE of 26.0% (certified at 25.28%) is realized by the local phase-modulated heterostructure PSC. Various characterization results confirm the key reasons for the superior performance of the CY-incorporated device over the reference device without CY. In CY-incorporated devices, we also demonstrate outstanding 96% and 71% PCE retention for the unencapsulated (85% relative humidity (RH), 25 °C, and 2000 h) and encapsulated (85% RH, 85 °C, and 1000 h) cells, respectively, and achieve a PCE of 22.7% for a 1.0-cm² large cell.