Component Distribution Regulation in Sn-Pb Perovskite Solar Cells through Selective Molecular Interaction.

Zhang, Wenxiao; Yuan, Haobo; Li, Xiaodong; Guo, Xuemin; Lu, Chunyan; Liu, Acan; Yang, Hui; Xu, Lin et al. · Adv Mater · 2023

basic_science · Level V

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Abstract

Tin-lead (Sn-Pb) perovskite solar cells (PSCs) with near-ideal bandgap still lag behind the pure lead PSCs. Disordered heterojunctions caused by inhomogeneous Sn/Pb ratio in the binary perovskite film induce large recombination loss. Here, an Sn-Pb perovskite film is reported with homogeneous component and energy distribution by introducing hydrazine sulfate (HS) in Sn perovskite precursor. HS can form hydrogen bond network and coordinate with FASnI<sub>3</sub> thus no longer bond with Pb<sup>2+</sup> , which reduces the crystallization rate of tin perovskite to the level of lead analog. The strong bonding between SO<sub>4</sub> <sup>2-</sup> and Sn<sup>2+</sup> can also suppress its oxidation. As a result, the Sn-Pb PSCs with HS exhibit a significantly improved V<sub>OC</sub> of 0.91 V along with a high efficiency of 23.17%. Meanwhile, the hydrogen bond interaction network, strong bonding between Sn<sup>2+</sup> and sulfate ion also improve the thermal, storage, and air stability of resulting devices.