The Controlling Mechanism for Potential Loss in CH3NH3PbBr3 Hybrid Solar Cells

We investigated moisture and thermal stability of MAPbBr(3) perovskite material. Cubic MAPbBr3 was found to be moisture-insensitive and can avoid the thermal stability issues introduced by low-temperature phase transition in MAPbI(3). MAPbBr(3) and MAPbI(3) hybrid solar cells with efficiencies of similar to 7.1% and similar to 15.5%, respectively, were fabricated, and we identified the correlation between the working temperature, light intensity, and the photovoltaic performance. No charge-carrier transport barriers were found in the MAPbBr(3) and MAPbI(3) solar cells. The MAPbBr(3) solar cell displays a better stability under high working temperature because of its close-packed crystal structure. Temperature-dependent photocurrent voltage characteristics indicate that, unlike the MAPbI(3) solar cell with an activation energy (EA) nearly equal to its band gap (E-g), the E-A for the MAPbBr(3) solar cell is much lower than its Eg. This indicates that a high interface recombination process limits the photovoltage and consequently the device performance of the MAPbBr(3) solar cell.