Efficiency enhancement of perovskite solar cell by using pre-heat treatment in two-step deposition method

The power conversion efficiency (PCE) of perovskite solar cell (PSC) is investigated by using pre-heat treatment of perovskite layer in two-step deposition method. In this work, the perovskite films are prepared by varying heat treatment conditions of lead iodide (PbI2) films and methylammonium iodide (MAI) solution before their reaction. The surface morphology is characterized by field emission scanning electron microscopy and crystal structure is investigated by X-ray diffractometry. It is found that the PSC device fabricated with pre-heat treatment of PbI2 films exhibit the highest PCE of 8.4% (compared to the device fabricated without pre-heat treatment of 1.4%). The efficiency enhancement can be attributed to morphological smoothness and pinhole-free of perovskite layer resulting in an increase of photocurrent. From photoluminescence results, it is found that the decay time of cells with pre-heat treatment is shorter suggesting faster charge transfer These results suggest that the pre-heat treatment of PbI2 films before spin coated MAI solution can be used to modify the perovskite layer and can enhance the performance of perovskite solar cells.