Rigid Amino Acid as Linker to Enhance the Crystallinity of CH3NH3PbI3 Particles

Abstract

Organic-inorganic hybrid perovskites have attracted extensive interest in recent years due to their remarkable properties in highly efficient solar cells. The quality of the perovskite thin films has been identified as a critical factor to affect the performances of the solar cells. To achieve uniform and dense perovskite films, many efforts have been attempted on controlling the crystallinity of the particles, grain size, as well as surface coverage. Using organic coupling agents to connect the mesoporous TiO2 with the perovskite film is an effective way to guide the growth of perovskite film. However, the influences of organic molecular configurations on the perovskite crystallization are still not being well studied. In this article, two amino acids, 4-aminobenzoic acid and 4-aminobutyric acid, are employed with similar molecular size and closed chain length to study the molecular rigidity of the organic coupling agents affecting the quality of perovskite films. Greatly improved perovskite film has been obtained with the template effect of rigid 4-aminobenzoic acid and thus the cell performance has been significantly increased.