Enhancement of thermoelectric performance of CH₃NH₃PbI₃ through strain driven topological phase transition and doping

Abstract

The effects of compressive strain, doping and temperature on the thermoelectric properties of CH3NH3PbI3 have been investigated by employing first principles based calculations and semi-classical Boltzmann theory. CH3NH3PbI3 displays a topological phase transition under 9.9% external compressive strain. Thermoelectric studies reveal that application of strain enhances the Seebeck coefficient for electron and hole-doped regions. This increment is attributed to the strain induced band inversion and modifications in the electronic density of states at the topological transition point. The strain driven topological phase transition produces a ZT value of 0.89 for hole-doped CH3NH3PbI3 at 800 K.