Retarding Crystallization for High-Quality Printable All-FA-Based Sn-Pb Perovskite Thin-Films and All-Perovskite Tandem Photovoltaic Devices

Improving the intrinsic stability of Tin-Lead (Sn-Pb) perovskite is of great significance to extend their lifetime of the solar devices. However, the presence of a considerable amount of volatile MA⁺ species in the advanced Sn-Pb perovskite films constrains their stability. Here, we report scalable blade coating high-quality all-FA-based Sn-Pb perovskite thin films by incorporating the precursor a small amount of thiosemicarbazide hydrochloride (TH). It is found that TH molecules not only suppress oxidation of Sn²⁺, thereby reducing electronic defects, but more importantly, retard crystallization process, which effectively eliminates the macroscopic defects at the buried interface. The combination of these two merits allows to produce high-quality all-FA-based Sn-Pb perovskites with significantly reduced nonradiative recombination, alongside marked improved intrinsic thermal stability. Eventually, the open-circuit voltage of the best-performing all-FA Sn-Pb solar devices rises from 801 to 856 mV, yielding a high efficiency of 20.16%. Mini-modules with active area of 2.048 and 11.28 cm² realize efficiencies of 19.02% and 18.37%, respectively. As well, the all-perovskite tandem devices are constructed, delivering a state-of-the-art high efficiency of 26.23%.