Study Of High Performance Perovskite Solar Cell

In 2009, perovskite solar cell was firstly reported. Several years later, the PCEs of perovskite solar cells have skyrocketed, superior to their organic rivals, and become comparable to silicon solar cell. It can be fabricated at low cost and low energy consumption. These outstanding characteristics promise its vast potential application.In this paper, we conducted some research in three areas as listed below:First of all, we studied the effect of chemical precursors on perovskite thin film. We studied how the ratio of MAI and PbCl₂ affect the performance of perovskite films by utilizing the co-evaporation technique. With varied ratio of the precusors, the morphology of perovskite film varied, showing diverse electrical and optical performance. When MAI is insufficient,the final product in the perovskite film has excess Pb I2 。 When MAI is excessive, the film shows porours morphology, and hydroscopicity property.Secondly, to improve the crystallization of perovskite films, solvent annealing technique and its work mechanism were studied. The grain size of perovskite film can be enlarged from 300 nm to 1000 nm when annealed in DMSO atmosphere. The defects of the film can be also reduced, along with improved device performance.Thirdly, charge transport layer is vital to performance of solar cells. We developed a new electron transport layer（ETL） of metal sulfide. We studied energy bands of metal sulfide and found that the mismatch of energy bands between perovskite and ETL impede electrons passing through the interface. The successful application of CdS ETL in solar cell provide possibility for developing flexible perovskite solar cells.Finally, how ETL works in perovskite cells is still under research. Through studying the device performance with varied ETL materials, we proposed an energy bending model. Base on the model, we explained that the “S” shape in J-V curve when single layer of PCBM is used, and also the reason why PCBM-BCP bi-ETL outperform their rivals.