Microstructurally Tailored Thin beta-Ag2Se Films toward Commercial Flexible Thermoelectrics

Aiming to overcome both the structural and commercial limitations of flexible thermoelectric power generators, an efficient room-temperature aqueous selenization reaction that can be completed in air within less than 1 min, to directly fabricate thin beta-Ag2Se films consisting of perfectly crystalline and large columnar grains with both in-plane randomness and out-of-plane [201] preferred orientation, is designed. A high power factor (PF) of 2590 +/- 414 mu W m(-1) K-2 and a figure-of-merit (zT) of 1.2 +/- 0.42 are obtained from a sample with a thickness of approximate to 1 mu m. The maximum output power density of the best 4-leg thermoelectric generator sample reach 27.6 +/- 1.95 and 124 +/- 8.78 W m(-2) at room temperature with 30 and 60 K temperature differences, respectively, which may be useful in future flexible thermoelectric devices.