Stable copper‐based 2D perovskite (NH3C3H6NH3)CuBr4 thin film processed from green solvent for thermoelectric application

Great achievements about lead‐based halide perovskites have been made in the fields of photovoltaic solar cells, light emitting diodes, photodetectors, and thermoelectric devices. However, the toxicity and instability of lead‐based materials hinder their practical application. Herein, we used propane‐1,3‐diammonium cation to construct a copper‐based halide perovskite material (NH3C3H6NH3)CuBr4 with a two‐dimensional layered structure. This material exhibits a suitable bandgap of 1.71 eV for a broad‐band absorption. Dense and flexible (NH3C3H6NH3)CuBr4 thin film can be obtained by simple spin‐coating of the solution using green solvent DMSO. Furthermore, (NH3C3H6NH3)CuBr4 shows excellent stability towards temperature, humidity and UV‐light. Finally, the (NH3C3H6NH3)CuBr4 thin film shows a reasonable Seebeck coefficient of −13.8 μV K−1 and a power factor of 1.70 μW m−1 K−2 at 298 K, demonstrating the great potential for flexible n‐type thermoelectric application. We report a n‐type copper‐based two‐dimensional perovskite (NH3C3H6NH3)CuBr4 towards thermoelectric application at room temperature. The (NH3C3H6NH3)CuBr4 thin films can be processed from green DMSO solvent and exhibit high stability towards air/UV light and decent thermoelectric performance. This material demonstrates the potential of Cu‐based perovskites in fabricating stable and flexible thermoelectric devices in an environmentally friendly way.