(The) controls of process condition for high efficiency organic-inorganic hybrid perovskite solar cells

Abstract

We studied the effects of post-synthesis thermal treatments on material properties of organic-inorganic hybrid perovskite films and their photovoltaic performance for Pb-based and Bi-based materials. Kelvin probe force microscopy revealed the existence of a positive potential barrier at grain boundaries, which is known to be beneficial by suppressing carrier recombination. The height of the barrier increased with the annealing duration, which directly correlated with the device performance. The origin of the potential barrier appeared to be chemical inhomogeneity as revealed by Nano-Auger electron spectroscopy. Qualitatively similar temperature-dependence of current-density vs bias characteristics were observed regardless of the annealing duration, where efficiency collapsed at low temperatures due to a diverging series resistance. We compared optical and structural properties of Bi-based perovskite material with different compositional ratio $(A_3B_2X_9 vs. AB_3X_{10})$