Defect Compensation and Lattice Stabilization Enables High Voltage Output in Tin Halide Perovskite Solar Cells

Abstract

Tin halide perovskite solar cells (PSCs) are regarded as the most promising lead‐free alternatives for photovoltaic applications. However, they still suffer from uncompetitive photovoltaic performance because of the facile Sn2+ oxidation and Sn‐related defects. Herein, a defect and carrier management strategy by using diaminopyridine (DP) and 4‐bromo‐2,6‐diaminopyridine (4BrDP) as multifunctional additives for tin halide perovskites is reported. Both DP and 4BrDP induced strong interaction with tin perovskites by coordinate bonding and N─H···I hydrogen bonding, which greatly suppresses the micro‐strain and Urbach energy of tin halide perovskite films. The strong hydrogen bonding inhibits the formation of I3− and related defect density. Meanwhile, the electron‐donor species of halogen bond in 4BrDP provides higher reactivity of 2 and 6 sites, which indicates stronger passivation ability with tin halide perovskites. These advances enable a champion power conversion efficiency (PCE) of 13.40% in 4BrDP‐processed devices with remarkable improvement in both open‐circuit voltage (Voc) of 881 mV and fill factor (FF) of 71.26%. The 4BrDP devices retain 91% and 82% of the pristine PCE after 2000 h storage in N2 atmosphere and 1000 h under 85 °C, respectively. Therefore, this work provides new insight into molecular design for high‐performance and stable lead‐free optoelectronics.

Improving Hybrid Tin Halide Layers by Melt Assisted Annealing for Lead‐Free Perovskite Solar Cells

“…As the small Urbach energy is usually related to the low density of defects, APZ additives tend to decrease the defect states in the perovskite layers. [53] These results are consistent with the improved quality and reduced band edge states of perovskite layers due to APZ additives.…”

Multi-functional molecule advancing the efficiency of pure 3D FASnI3 perovskite solar cells based on the tin tetraiodide reduction method

“…This suggests that the Sn 2+ generated by the TTR method interacts more strongly with DMF/DMSO. 30,31 Moreover, by comparing the redox potential (Table S2†), the higher reduction potential of Sn favors the formation and stability of Sn 2+ in the presence of SnI 4 . 32…”

Tailoring Low-Dimensional Phases for Improved Performance of 2D–3D Tin Perovskite Solar Cells

“…Based on the D-HLH optimized tin perovskite films, inverted tin PSCs are fabricated by adopting common PCBM as an electron transport material rather than the expensive ICBA. 35 The optimized devices show a champion PCE of 12.45%, significantly surpassing the control device, and the device stability is also improved.…”

“…Moreover, the D-HLH can suppress the oxidation of Sn 2+ and reduce the defect density of the 2D–3D tin perovskite film, which is favorable for improving the device performance. Based on the D-HLH optimized tin perovskite films, inverted tin PSCs are fabricated by adopting common PCBM as an electron transport material rather than the expensive ICBA . The optimized devices show a champion PCE of 12.45%, significantly surpassing the control device, and the device stability is also improved.…”