Understanding the synergistic influence of the propylammonium bromide additive and erbium-doped CsPbI2Br for highly stable inorganic perovskite solar cells

Inorganic cesium lead halide perovskites have gained increasing attention to boost photovoltaic performance and device stability. Nevertheless, the photoactive to photo-inactive phase transition under ambient conditions hampers its further enhancement. Here, we varied various amounts of propylammonium bromide (PABr) additive in the CsPbI2Br perovskite and further varied the erbium (ErCl3)-doped CsPbI2Br (herein CsPb1-nErnI2BrXn) (where X = Cl; 0 <= n < 1) perovskite. Further, in the optimized (CsPb0.97Er0.03I2BrCl0.09) composition, we studied the influence of various amounts of the PABr additive. Our results clearly show the PABr additive added film results in high-quality surface morphology, high crystallinity, and decreased trap-state density. Accordingly, our champion CsPb0.97Er0.03I2BrCl0.09 + 2 mg ml(-1) PABr (CsEr-PA)-based inorganic perovskite solar cell (IPVSC) device showed 16.74% power conversion efficiency (PCE), which is much higher than that of bare (13.20%) and CsPb0.97Er0.03I2BrCl0.09-based perovskite devices (15.73%). In addition, the CsEr-PA-based IPVSC device revealed increased long-term stability, which maintained 90% of its initial PCE at 65 degrees C and thermal stress of over 400 h under ambient conditions. These dual stabilization strategies cover a new way to increase the photovoltaic performance of IPVSCs.

Automated summary

Adding propylammonium bromide (PABr) and erbium (ErCl3) doping to CsPbI2Br perovskite can improve the photovoltaic performance and stability of inorganic cesium lead halide perovskite solar cells. The optimized composition (CsPb0.97Er0.03I2BrCl0.09) with 2 mg ml(-1) PABr additive shows high-quality surface morphology, high crystallinity, and reduced trap-state density. The resulting CsEr-PA-based inorganic perovskite solar cell achieves a power conversion efficiency (PCE) of 16.74%, higher than the bare (13.20%) and CsPb0.97Er0.03I2BrCl0.09-based perovskite devices (15.73%). Additionally, the CsEr-PA-based IPVSC device exhibits increased long-term stability, maintaining 90% of its initial PCE after 400 hours of thermal stress at 65 degrees C under ambient conditions. These dual stabilization strategies provide a new approach to enhance the photovoltaic performance of inorganic perovskite solar cells.