Reducing Perovskite/C60 Interface Losses via Sequential Interface Engineering for Efficient Perovskite/Silicon Tandem Solar Cell

Wide‐bandgap (WBG) perovskite solar cells hold tremendous potential for realizing efficient tandem solar cells. However, nonradiative recombination and carrier transport losses occurring at the perovskite/electron‐selective contact (e.g. C60) interface present significant obstacles in approaching their theoretical efficiency limit. To address this, a sequential interface engineering (SIE) strategy that involves the deposition of ethylenediamine diiodide (EDAI2) followed by sequential deposition of 4‐Fluoro‐Phenethylammonium chloride (4F‐PEACl) is implemented. The SIE technique synergistically narrows the conduction band offset and reduces recombination velocity at the perovskite/C60 interface. The best‐performing WBG perovskite solar cell (1.67 eV) delivers a power conversion efficiency (PCE) of 21.8% and an impressive open‐circuit voltage of 1.262 V. Moreover, through integration with double‐textured silicon featuring submicrometer pyramid structures, a stabilized PCE of 29.6% is attained for a 1 cm2 monolithic perovskite/silicon tandem cell (certified PCE of 29.0%). This work implements a sequential interface engineering (SIE) strategy that involves the deposition of ethylenediamine diiodide followed by sequential deposition of 4‐Fluoro‐Phenethylammonium chloride on perovskite film. This technique synergistically narrows the conduction band offset and reduces recombination velocity at the perovskite/C60 interface. Based on the SIE strategy, the PCE of 29.6% for a 1 cm2 monolithic perovskite/silicon tandem cell is achieved.