Boosting interfacial contact for the NiOx-based inverted perovskite solar cells via D-A type semiconductor

Inorganic NiOx x emerges as a promising hole transport material for inverted perovskite solar cells (PSCs). However, the NiOx/perovskite x /perovskite interface in PSCs typically faces challenges such as energy level mismatch, existence of surface defects, complex active species etc., hindering the enhancement of power conversion efficiency (PCE) and device stability for NiOx-based x-based PSCs. Herein, it is proposed an interfacial modification strategy with a donor-acceptor type semiconductor, in which the planar tetrathienopyrrole as electron-acceptor and triphenylamine-free indeno[1,2-b]carbazole as electron-donor. When fabricated as the interlayer between perovskite and NiOx, x , this semiconductor effectively tunes the interfacial energy level alignment, facilitates the hole extraction/transfer, bifacially passivates the defect sites within the interface, and suppresses the detrimental reaction between perovskite and NiOx. x . As a result, a significantly improved fill factor and open circuit voltage is achieved, attributing a champion PCE of 19.05 % with negligible hysteresis, outstripping that with pristine NiOx x (18.12 %). Moreover, after CQ37 modification, PSC maintains over 78 % of its original PCE following 2000 hat room temperature, which compares excellently with that of the pristine NiOx-based x-based device. This study renders the promise CQ37 to address the challenging issues that have hindered the process of NiOx-based x-based PSCs.