LAUSR

Inorganic CsSnI3 with low toxicity and a narrow band gap is a promising photovoltaic material. However, the performance of CsSnI3 perovskite solar cells (PSCs) is much lower than that of Pb-based and hybrid Sn-based (e. g. CsPbX3 and FASnX3 ) PSCs, which might be attributed to its poor film-forming property and deep traps induced by Sn4+ . Here, a bifunctional additive carbazide (CBZ) was adopted to deposit a pinhole-free film and remove the deep traps via two-step annealing. The lone electrons of the -NH2 and -CO units in CBZ can coordinate with Sn2+ to form a dense film with large grains during the phase transition at 80°C. The decomposition of CBZ can reduce Sn4+ to Sn2+ during annealing at 150°C to remove deep traps. Compared with the control device (4.12%), the maximum efficiency of the CsSnI3 :CBZ PSC reached 11.21%, which is the highest efficiency of CsSnI3 PSC reported to date. A certified efficiency of 10.90% was obtained in an independent photovoltaic testing laboratory. In addition, the unsealed CsSnI3 :CBZ devices maintained initial efficiencies of approximately 100%, 90%, and 80% under an inert atmosphere (60 days), standard maximum power point tracking (650 h at 65°C), and ambient air (100 h), respectively. This article is protected by copyright. All rights reserved.