Researchers from Australia’s University of New South Wales (UNSW) Sydney have developed a defects passivation strategy for chloride-iodide-based perovskite. The team targeted the hard-to-avoid local defects in chloride-iodide-based perovskites, using two organic halide passivators named 4-chlorobenzylammonium chloride and 4-chlorobenzylammonium bromide.
The scientists passivate both the surface and bulk of the perovskite thin film. The surface of the perovskite thin film is passivated with the bulky organic benzylammonium cations. The bulk of the perovskite thin film is passivated with the diffusion of chlorine or bromine.
With different combinations of the two passivators, the team varied the chlorine range from 50% to 100% and the bromine range from 25% to 50%. The scientists found the champion cell performance for 75% chlorine and 25% bromine combination.
The enhancement of device efficiency was around 15% compared to the control device and the device stability was also considerably enhanced.
