CsPbI2.69Br0.31 Solar Cells from A Low-Temperature Fabrication

A low-temperature one-step solution process for cesium lead iodide perovskite solar cells (PSCs) was developed by adding hydrobromic acid (HBr) into the precursor solution. CsPbI2.69Br0.31 was confirmed as the best structure, with a bandgap of 1.75 eV. A 9.58% power conversion efficiency (PCE) was achieved, which was the highest for PEDOT:PSS-based inorganic perovskite solar cells. The device efficiency decreased 4% after being stored in N2 for 1200 hours.