Enhanced thermoelectric performance of Cu2Se thin film derived from potential barrier scattering by incorporating SnSe nano-dispersions

Incorporating nano-dispersions into thermoelectric (TE) materials is an effective approach to enhance the TE properties. Herein, the TE performance of Cu2Se thin film is significantly enhanced by incorporating highly dispersed SnSe nano-inclusions. The high power factor (PF, ∼11.0 μW cm−1 K−2, 310 K) at near room temperature is achieved mainly due to the enhanced energy filtering effect that originated from the potential barrier difference. The total thermal conductivity is decreased owing to the simultaneously reduced electrical conductivity and enhanced phonon scattering. As a result, a high zT value (∼0.59 at 375 K) is achieved, which is about 12 times of pristine Cu2Se film. Remarkably, the calculated average zT values of Cu2Se/SnSe films from 310 to 375 K greatly exceed those of the pristine Cu2Se film, as well as the most state-of-the-art studies. High room-temperature PF and average zT value are crucial for expanding the practical application of Cu2Se at near room temperature. This work provides a feasible strategy to optimize the zT values of some other TE films by introducing nano-dispersions.