Electron Delocalization and Structure Coupling Promoted π-Conjugated Charge Transport in a Novel [Ga-Tpy2]PbI5 Perovskite-like Single Crystal.

Abstract

Multidimensional perovskite techniques are of intense research interest since they are proved to be advantageous to enhance the perovskite stability. Thereinto, the structure engineering strategy has been widely used to regulate the low dimensional (LD) perovskite structures and obtain expected optoelectronic properties. In this work, we intercalate a thus far unreported metallic coordination compound [Ga-Tpy2]3+ (Tpy: 2,2 ;6 ,2″-terpyridine) to the inorganic Pb-I building block as the A-site organic group, and the zero dimensional (0D) [Ga-Tpy2]PbI5 perovskite-like single crystal is obtained. This material displays suitable band edge levels, which enable its potential application as light absorber in solar cells. The DFT calculations manifest delocalized charge distribution on Tpy ligands that can facilitate electron transport, which is attributed to the formation of a double hybrid coordinate bond, i.e., σ bonds and π bonds, between Ga3+ ions and Tpy ligands. These coordinate bonds make metallic complexes promising molecules to regulate structure-associated optoelectronic performances of the LD perovskites.