Effects of precursor solution composition on the performance and I-V hysteresis of perovskite solar cells based on CHNHPbICl.

Precursor solution of CHNHPbICl for perovskite solar cells was conventionally prepared by mixing PbCl and CHNHI with a mole ratio of 1:3 (PbCl:CHNHI). While in the present study, CHNHPbICl-based solar cells were fabricated using the precursor solutions containing PbCl and CHNHI with the mole ratios of 1:3, 1.05:3, 1.1:3, and 1.15:3, respectively. The results display that the solar cells with the mole ratio of 1.1:3 present higher power conversion efficiency and less I-V hysteresis than those with the mole ratio of 1:3. Based on some investigations, it is concluded that the higher efficiency could be due to the smooth and pinhole free film formation, high optical absorption, suitable energy band gap, and the large electron transfer efficiency, and the less I-V hysteresis may be attributed to the small low frequency capacitance of the device.