Realizing high thermoelectric performance flexible free‐standing PEDOT:PSS/Bi 0.5 Sb 1.5 Te ₃ composite films for power generation

Flexible thermoelectrics provide a distinct solution for developing sustainable and portable power supplies. Inorganic/organic material compositing is an effective strategy to induce a significant enhancement of thermoelectric (TE) performance. However, the poor electrical performance of inorganic/organic material is attributed to the poor carrier transport between organic/inorganic interfaces induced by the low contribution of composited inorganic materials. Herein, we prepared a high room temperature figure‐of‐merit ( ZT ) value of ~ 0.19 and high bending resistance (surviving 1200 bending cycles at the bending radius of 16.5 mm) of p‐type poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS)/Bi 0.5 Sb 1.5 Te 3 free‐standing composite film via a facile vacuum‐assisted filtration approach. Compositing Bi 0.5 Sb 1.5 Te 3 nano‐spherical particles into PEDOT:PSS results in the optimized interfacial contact and carrier concentration, leading to a high Seebeck coefficient of ~ 43.79 μV·K −1 . Accordingly, a high‐power factor of ~ 1.52 μW·cm −1 ·K −2 is achieved in the PEDOT:PSS/Bi 0.5 Sb 1.5 Te 3 composite film at room temperature. In addition, the PEDOT:PSS/Bi 0.5 Sb 1.5 Te 3 interfaces with phase boundaries, nanograins and point defects could further decrease the thermal conductivity to ~ 0.20 W·m −1 ·K −1 , leading to a high ZT value. Furthermore, a 6‐leg free‐standing film device was assembled, which provided an output power of 44.94 nW. This study demonstrates that free‐standing organic/inorganic composite films are effective power sources for wearable electronic products.