Mutually Tuned Dual Additive Engineering Synergistically Enhances the Photovoltaic Performance of Tin-Based Perovskite Solar Cells

Abstract

Tin-based perovskite solar cells (T-PSCs) have become the star photovoltaic products in recent years due to their low environmental toxicity and superior photovoltaic performance. However, the easy oxidation of Sn 2+ and the energy level mismatch between the perovskite film and charge transport layer limit its efficiency. In order to regulate the microstructure and photoelectric properties of tin-based perovskite films to enhance the efficiency and stability of T-PSCs, guanidinium bromide (GABr) and organic Lewis-based additive methylamine cyanate (MAOCN) are introduced into the FA 0.9 PEA 0.1 SnI 3 -based perovskite precursor. A series of characterizations show that the interactions between additive molecules and perovskite mutually reconcile to improve the photovoltaic performance of T-PSCs. The introduction of GABr can adjust the band gap of the perovskite film and energy level alignment of T-PSCs. They significantly increase the open-circuit voltage (V oc ). The MAOCN material can form hydrogen bonds with SnI 2 in the precursor, which can inhibit the oxidation of Sn 2+ and significantly improve the short-circuit current density (J sc ). The synergistic modulation of the dual additives reduces the trap-state density and improves photovoltaic performance, resulting in an increased champion efficiency of 9.34 for 5.22% of the control PSCs. The unencapsulated T-PSCs with GABr and MAOCN dual additives prepared in the optimized process can retain more than 110% of their initial efficiency after aging for 1750 h in a nitrogen glovebox, but the control PSCs maintain only 50% of their initial efficiency kept in the same conditions. This work provides a new perspective to further improve the efficiency and stability of T-PSCs.

Carrier Transport in Low‐Dimensional Tin Perovskite Solar Cells

“…[ 69 ] Liu et al introduced two additives, namely guanidine bromide (GABr) and methylamine cyanate (MAOCN) in TPSCs. [ 70 ] GABr can adjust the bandgap and energy level arrangement of films, and MAOCN can reduce the proportion of Sn 4+ . Benefiting from the synergistic effect of the two additives, the defects can be reduced and the device with a PCE of 9.34% can be obtained.…”