Flexible Ag2Se-based thin-film thermoelectrics for sustainable energy harvesting and cooling
Wenyi Chen, Meng Li, Xiaodong Wang, Joseph Otte, Min Zhang, Chengyang Zhang, Tianyi Cao, Boxuan Hu, Nanhai Li, Wei‐Di Liu, Matthew S. Dargusch, Jin Zou, Qiang Sun, Zhi‐Gang Chen, Xiao‐Lei Shi
Abstract
Abstract The high cost and complexity of fabrication limit the large-scale application of flexible inorganic thermoelectric materials. Currently, Bi 2 Te 3 -based materials are the only commercially viable option, but the inclusion of Te significantly increases production costs. This study presents a simple and cost-effective method for fabricating flexible Ag 2 Se films, employing a combination of solvothermal synthesis, screen printing, and spark plasma sintering. The incorporation of a small amount of Te improves film density and facilitates Te diffusion doping, leading to Ag 2 Se films with a high power factor of 25.7 μW cm −1 K −2 and a figure of merit ( ZT ) of 1.06 at 303 K. These films exhibit excellent flexibility, retaining 96% of their performance after 1000 bending cycles at a 5 mm bending radius. Additionally, we design a flexible thermoelectric device featuring a triangular p-n junction structure based on these films. This device achieves a normalized power density of 4.8 μW cm −2 K −2 at a temperature difference of 20 K and a maximum cooling of 29.8 K with an input current of 92.4 mA. These findings highlight the potential of this fabrication method for developing thermoelectric materials and devices for energy harvesting and cooling applications.