Achieving\nHigh Thermoelectric\nPerformance in Bi<sub>2</sub>(Te, Se)<sub>3</sub> Thin Film with (00<i>l</i>)‑Oriented\nby Incorporating Tellurization and Selenization Processes

Flexible thermoelectric (TE) generators\nhave received\ngreat attention\nas a sustainable and reliable option to convert heat from the human\nbody and other ambient sources into electricity. This study provides\na synthesis route that involves thermally induced diffusion to introduce\nTe and Se into Bi, fabricating an n-type Bi–Te–Se flexible\nthin film on a flexible substrate. This specific synthesis alters\nthe crystal orientation (00<i>l</i>) of the thin film, improving\nin-plane electrical transportation and optimizing carrier concentration.\nConsequently, Bi<sub><i>x</i></sub>Te<sub><i>y</i></sub>Se<sub>0.42</sub> enhanced both the Seebeck coefficient and\nelectrical conductivity, achieving a power factor of 17.1 μW\ncm<sup>–1</sup> K<sup>–2</sup> at room temperature.\nThe TE device assembled with p-type Sb<sub>2</sub>Te<sub>3</sub> exhibited\nexceptional flexibility with only a 26.2% change in resistance after\n1000 times of bending at a radius of about 6 mm. The resistance change\nwas further reduced to 7.5% after the application of a vinyl laurate\ncoating. The fabricated TE device generated an ultrahigh output power\nof 792 nW with a temperature difference of 30 K.