Dual-side synergistic modification for inverted CsPbI3 inorganic perovskite solar cells

CsPbI 3 is a promising light-absorbing material for photovoltaics due to its excellent thermal stability and optimal bandgap. However, poor film quality and interfacial defects severely restricted the improvement of such devices. In addition, systematic studies on the selection of hole transport layers for inverted CsPbI 3 perovskite solar cells remain limited. In this work, we systematically compared the optoelectronic properties of four HTLs and their effects on the quality of CsPbI 3 films, including NiO X , MeO-2PACz, and their composite films. Specially, the NiO X /MeO-2PACz composite HTLs demonstrated improved substrate coverage and enhanced charge transport characteristics, thereby improving the crystallinity of CsPbI 3 films and the performance of the final device. Furthermore, dimethylammonium chloride (DMACl) compound was employed as a CsPbI 3 surface passivator, with Cl - compensating for I - vacancies to suppress Pb 0 defects and DMA + improving moisture stability. Additionally, the energy level mismatch between the ETL and PVK was significantly reduced after DMACl passivation. Through this dual-side synergistic strategy, the best-performing inverted CsPbI 3 PSCs achieve an impressive power conversion efficiency (PCE) of 15.05 % and a short-circuit current density (J sc ) of 20.9 mA cm −2 . Additionally, the unencapsulated optimized device retains 80 % of its initial PCE after 800 h of storage in dry air.