Calcium manganate: A promising candidate as buffer layer for hybrid halide perovskite photovoltaic-thermoelectric systems

摘要

We have systematically studied the feasibility of CaMnO thin film, an n-type perovskite, to be utilized as the buffer layer for hybrid halide perovskite photovoltaic-thermoelectric device. Locations of the conduction band and the valence band, spontaneous polarization performance, and optical properties were investigated. Results indicate the energy band of CaMnO can match up well with that of CHNHPbI on separating electron-hole pairs. In addition, the consistent polarization angle helps enlarge the open circuit voltage of the composite system. Besides, CaMnO film shows large absorption coefficient and low extinction coefficient under visible irradiation, demonstrating high carrier concentration, which is beneficial to the current density. More importantly, benign thermoelectric properties enable CaMnO film to assimilate phonon vibration from CHNH3PbI. All the above features lead to a bright future of CaMnO film, which can be a promising candidate as a buffer layer for hybrid halide perovskite photovoltaic-thermoelectric systems.