Dithiols enhance the photovoltaic performance and stability of perovskite solar cells and modules by elongating the carrier lifetime

Metal-halide perovskite solar cells (PSCs) exhibit outstanding efficiencies when fabricated as mm-sized cells, but the fabrication of high-performing larger-area modules presents a challenge. Emerging evidence suggests the serious recombination reaction caused by the limited carrier lifetime is the bottleneck, because we lack effective strategy to deposit large-area perovskite film with sufficient long carrier lifetime. Herein, we report on a strategy of modulating the formation of perovskite film on larger-area substrates via introducing alkyl dithiol additives. Among the dithiols with different lengths, we find hexane-1,6-dithiol can effectively elongate carrier lifetime of perovskite film from 1.5 to 7.6 μs, which is due to the suppression of the formation of inactive PbI2 and hexagonal δH phase, along with the enlarged grain size. As a result, we improved the efficiency of solar cells (0.16 cm2) from 21.8% to 23.5%, as well as 16.9%–18.1% for the mini-modules (10.0 cm2). More importantly, the modified modules retained 92% of their initial efficiencies after 500-h aging under ambient condition without encapsulation (ISOS-D-1). This dithiol additive strategy shows great promise for pursuing high-performance PSCs.