Anti-solvent treatment time approach to high efficiency perovskite solar cells with temperature of coating environmental

Abstract

The fabrication conditions of the light absorber layer (organic-inorganic halide perovskite) have a very large effect on the device performance in perovskite solar cells. In case of using the 1-step anti-solvent treatment (AST), their show very different characteristics depending on the AST time, amount, and temperature, etc. Here, we determined the optimal AST time for the synthesis of perovskite light absorber layer in relation to the turbidity point (TP) of the precursor solution during spin coating according to the temperature inside the glovebox. The TP was examined according to the fluid flow of the host solvent, and it depended on various conditions, such as the temperature and substrate. The measured TP was almost identical to the estimated TP, and both tended to decrease as the internal temperature increased. The AST time and the internal temperature of the glovebox significantly affected the crystallinity and device performance of the perovskite, and the best device performance of 18.9% for a methylammonium lead iodide (MAPbI3) solar cell with n-i-p normal planar structure was achieved by applying an AST time of 9.5 s at 25 degrees C. Drive-level capacitance profiling and thermal admittance spectroscopy results confirmed that the optimal AST time of 9.5 s yielded a minimum trap density of 2.1 x 1015/cm3, which was related to the trap states of MAPbI3.