Study On Photoeletric Performance Of Perovskite Solar Cells Based On Morphology Regulation Of Light Active Layer

Recently, perovskite solar cells(PSCs) have become a research hotspot in photovoltaic technology as their low price, simple fabrication process, and high conversion efficiency, etc. Perovskite solar cells have mesoporous and planar structures, and the organic-inorganic hybrid lead trihalides are the key component in all types of PSCs. Owing to the suitable band gap and excellent crystallization property, perovskite materials present strong light absorption, high carrier mobility and long carrier diffusion length. However, photovoltaic performance of perovskite material shows strong dependence on their composition and morphology. Therfore, control of composition and structure of perovskite material is significant for high performance perovskite solar cells.We mainly investigated the problem of effective control methods of perovskite film in both mesoporous and planar structure PSCs. For mesoporous one, we attempted to modify the dispersion of perovskite material in porous TiO2 layer and enhance the coverage of perovskite material on porous TiO2 layer by controlling perovskite crystal nucleation-growth rate and perovskite dissolving-recrystallizing processes. In regard to planar PSCs, we explored preliminarily the effect of spinning rate and annealing process on perovskite films. Additionally, we researched the influence of perovskite morphology on charge transfer and recombination processes at TiO2/perovskite interface. The main results are listed as follows:1. Benzylammonium iodide(C6H5CH2NH3I, BAI) or ammonium iodide(NH4I) as additives were utilized to fabricate perovskite films in one-step solution deposition method. By adding proper amount of BAI or NH4 I, photon-to-electricity conversion efficiencies of corresponding mesoporous PSCs increased from 6.83% to 9.05% and 9.49%, respectively.2. DMSO/CBZ, DMF/CBZ, and GBL/CBZ mixed solutions were employed to post-treating perovskite active layers, which were prepared by traditional sequential deposition process. The efficiencies of assembled PSCs with mesoporous layer obviously rose from 10.10% to 11.68%, 11.82%, and 10.66%, respectively.3. A flat and compact high-quality CH3NH3PbI3-xClx perovskite layer was obtainted via regulating the spin-coating speed and annealing time. The average conversion efficiency of PSCs was about 13%, and the optimized one of 15.48% was achieved.A series of perovskite morphology controlling techniques were investigated in this research. We successfully improved the quality of perovskite film and enhanced the photovoltaic performance of corresponding PSCs. This research is meaningful for developing high performance perovskite solar cells in future.