Abstract

Perovskite solar cells (PSCs) have made remarkable strides in achieving high power conversion efficiency, but their commercialization is still challenged by stability issues. Formamidinium (FA)-based two-dimensional (2D) perovskites have emerged as highly promising candidates due to the outstanding optoelectronic characteristics exhibited by inherent FA-based perovskites and enhanced environmental stability provided by 2D structures. The efficiency and stability of FA-based 2D PSCs are still relatively low.

In the first work using one-step deposition method. We tuned the Pb-I octahedral twisting and lattice distortion by organic spacer cation engineering to stabilize the FA-based 2D perovskite lattice. We further modulated the crystallization kinetics with a molecular-type Selenourea (SU) additive to inhibit the in-plane growth of quantum wells in 2D perovskites. The optimized FA-based 2D PSCs achieved a record-high power conversion efficiency (PCE) of 20.03% and exhibited less than 1% efficiency degradation after operating at maximum power point for 1000 hours.[1]

In the second work, we developed an additive-stabilized spacer-cation-preponed two-step deposition method to achieve the out-of-plane orientation and grain sizes larger than 5 µm in 2D perovskites. The optimized 2D PSCs achieved a high PCE of 21.16% and a short-circuit current of 23.71 mA cm⁻², among the highest in 2D PSCs. The PSCs demonstrate remarkable stability, with a PCE decrease of less than 5% after exposure to 65±10% humidity for 1100 hours, operation at 85°C for 1077 hours, or continuous illumination for 1045 hours.[2]

References
[1].  Zeng, Kong, Liang, Li, Lvtao, Su, Wang, Peng, Ye, Chen, Gao, Huang, Zheng, and Yang, Advanced Materials  35, 2306051, 2023.

[ 2].  Zeng, Su, Kong, Li, Liang, Zhang, Wang, Zhang, Lvtao, Liu, Gao, Huang, Yang, and Zheng, Energy & Environmental Science 17, 8284 2024.