Nanoengineering Approach toward High Power Factor Ag₂Se/Se Composite Films for Flexible Thermoelectric Generators

Herein, a flexible Ag₂Se/Se composite film with a high power factor has been fabricated on a nylon membrane. The film has a high density and contains well-crystallized Ag₂Se grains and embedded Se nanoinclusions, which exhibits not only excellent flexibility but also a comparably large room-temperature power factor and Seebeck coefficient of up to 2023 μW m^-1 K^-2 and -155 μV K^-1, respectively. The high Seebeck coefficient is ascribed to the energy-filtering effect as caused by the Se/Ag₂Se heterointerface. The assembled flexible thermoelectric generator (4-leg) exhibits a maximum output power of 1135 nW and a power density of up to 16.4 W m^-2 when the applied temperature difference is 30 K. This work offers a feasible method to design high-performance and low-cost flexible thermoelectric generators used for wearable electronics.