Constant illumination improves photovoltaic efficiency of hybrid perovskite crystal

Perovskite minerals have been investigated for some time as alternatives to crystalline silicon for photovoltaic cells, as they may be cheaper and easier to manufacture. A team at Rice University and Los Alamos National Laboratory has now discovered that the properties of a particular perovskite compound can be improved simply by illuminating it.

The team, led by Aditya Mohite and David Tsai, is investigating hybrid perovskite compounds with the general formula of AMX3, where A is a cation, M a divalent metal, and X is a halide. "It's a polar semiconductor with a direct band gap similar to that of gallium arsenide,” Mohite said.

Published in Science, the research explains that under normal circumstances these materials have a strained crystal structure, with a distorted lattice. But when illuminated, the lattice relaxes and uniformly expands in all directions. This aligns the crystal planes cures defects in the structure, which makes it easier for electrons to move through the system and deliver energy to end-user devices.