Photo-enhanced seebeck coefficient by photoinduced carrier dedoping in air-stable MAPbI3

We present an enhanced photo-Seebeck effect in air-stable MAPbI(3) by optical gating, where both the Seebeck coefficient (SC) and the electrical conductivity increase significantly when illuminated by a laser diode. A PbI2-rich MAPbI(3) perovskite pellet exhibited n-type charge carrier transport and showed a significant increase in the magnitude of the SC in air upon illumination. Compared with the p-type perovskite, the n-type MAPbI(3) perovskite showed higher Seebeck enhancement, along with higher photoconductivity. This indicates that the residual PbI2 in the n-type perovskite accelerates photoinduced charge transfer at the MAPbI(3)/PbI2 interface. The enhanced photo-Seebeck effect through dedoping induced by charge transfer can be applied to increase the thermoelectric figure of merit (ZT) in thermoelectric materials using non-destructive methods.