  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.
