Conjugated polyelectrolyte doped perovskite films with enhanced photovoltaic performance and stability

Perovskite solar cells (PSCs) have achieved great success in the past few years because of outstanding photovoltaic performance. However, the existence of electronic trap states in the perovskite film is an obstacle for the fabrication of high-performance and stable PSCs. Herein, a linear conjugated polyelectrolyte was developed and employed as a dopant to improve the performance and stability of the perovskite film. The PPNNA doping can passivate surface defects to reduce the electronic trap states in the perovskite film, while simultaneously enhancing the electron extraction and transport to achieve high-efficiency solar cells. Furthermore, the PPNNA-doped perovskite film shows better stability from efficient surface passivation. The optimal 0.4% PPNNA-doped device exhibits better photovoltaic efficiency (20.38%) with enhanced device stability as compared to the control device (18.51%). This novel method by doping with the conjugated polyelectrolyte provides a pathway to fabricate high-efficiency and stable inverted PSCs.