There are several ways to enhance the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Science (IF 47.728) published a study in July 2022. In halide perovskite solar cells, the formation of secondary-phase excess lead iodide (PbI₂) has some positive effects on power conversion efficiency (PCE) but may be detrimental to device stability and lead to large hysteresis effects in voltage sweeps.

To solve this problem, the research team converted PbI₂ into an inactive (PbI₂)₂RbCl compound by doping RbCl, which effectively stabilized the perovskite phase. With this method, the researchers successfully obtained a certified power conversion efficiency of 25.6% for a FAPbI₃ (FA, formamidinium) perovskite solar cell!

The device retained 96% of the original PCE values after 1000 hours of storage, and after 500 hours of thermal stability testing at 85°C, the device retained 80% of the original PCE value of power conversion efficiency.

The research used solar simulator, QE-R quantum efficiency measurement system, and electroluminescence efficiency test system LQ-50X of Enlitech. Research indicates that 5% RbCl doping is the optimal condition. It can generate a passivated inactive (PbI₂)₂RbCl phase and stabilize the perovskite phase and reduce its bandgap.

The method proposed in this study can improve the stability and efficiency, which will provide a new direction and promote the development of perovskite solar cells; there is also potential for use in other optoelectronic devices such as light-emitting diodes and photodetectors.