Bandgap widening by pressure-induced disorder in two-dimensional lead halide perovskite

Tuning the structure of organic–inorganic perovskites by pressure holds great promise for discovering materials with favorable properties. However, most of their high-pressure structures cannot be preserved at ambient conditions and little is known about how to control the properties of these materials recovered from high pressure. Here, we have manipulated the bandgap in a high-pressure-treated 2D organic-inorganic halide perovskite. We find that the bandgap of this compound can be largely altered by pressure-induced lattice disorder. Below 25 GPa, the phase transition is reversible and the thus-produced lattice distortion cannot be preserved after pressure release. In contrast, for the sample treated above 25 GPa, the structural disorder can be preserved at ambient pressure. Consequently, the bandgap of the sample can be profoundly tuned from 2.98 to 3.46 eV. These findings offer an extraordinary example for manipulating the structure and electronic properties of organic–inorganic perovskites by high pressure treatment.