Tuning of the Thermoelectric Figure of Merit of CH$_3$NH$_3$MI$_3$ (M=Pb,Sn) Photovoltaic Perovskites

TL;DR

This study explores how doping strategies can enhance the thermoelectric efficiency of hybrid perovskite materials, potentially reaching performance levels comparable to leading thermoelectric compounds.

Contribution

It demonstrates that doping can significantly improve the thermoelectric figure of merit in CH$_3$NH$_3$MI$_3$ perovskites, a novel approach for these photovoltaic materials.

Findings

Pristine samples show low $ZT$ values.

Photoinduced and chemical doping can increase $ZT$ toward unity.

Doping optimization could make these materials competitive thermoelectrics.

Abstract

The hybrid halide perovskites, the very performant compounds in photovoltaic applications, possess large Seebeck coefficient and low thermal conductivity making them potentially interesting high figure of merit ($ZT$) materials. For this purpose one needs to tune the electrical conductivity of these semiconductors to higher values. We have studied the CH$_3$NH$_3$MI$_3$ (M=Pb,Sn) samples in pristine form showing very low $ZT$ values for both materials; however, photoinduced doping (in M=Pb) and chemical doping (in M=Sn) indicate that, by further doping optimization, $ZT$ can be enhanced toward unity and reach the performance level of the presently most efficient thermoelectric materials.