Suppressing defects through the synergistic effect of a Lewis base and a Lewis acid for highly efficient and stable perovskite solar cells

By Fei Zhang, Dongqin Bi, N. Pellet, C. Xiao, Zhen Li, J. Berry, S. M. Zakeeruddin, K. Zhu, M. Graetzel. 2018

193 citations recorded by the source corpus.

Achieving long-term operational stability at a high efficiency level for perovskite solar cells is the most challenging issue toward commercialization of this emerging photovoltaic technology. Here, we investigated the cooperation of a Lewis base and a Lewis acid by combining commercial bis-PCBM mixed isomers as the Lewis acid in the antisolvent and N-(4-bromophenyl)thiourea (BrPh-ThR) as the Lewis base in the perovskite solution precursor. The combination of the Lewis base and the Lewis acid synergistically passivates Pb2+ and PbX3− antisite defects, enlarges the perovskite grain size, and improves charge-carrier separation and transport, leading to improved device efficiency from 19.3% to 21.7%. In addition, this Lewis base and acid combination also suppresses moisture incursion and passivates pinholes generated in the hole-transporting layer. The unsealed devices remained at 93% of the initial efficiency value in ambient air (10–20% relative humidity) after 3600 h at 20–25 °C and dropped by 10% after 1500 h under continuous operation at 1-sun illumination and 55 °C in nitrogen with maximum power-point tracking.

Subfields: Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/bd4e8dbe527c360f2f0c224fd16977366d1ebbb2