Charge localization induced tunable thermopower in ZnSb intercalated polyaniline:CSA flexible films
Anmol Sharma, Nagendra S. Chauhan, Masako Nishimagi, Takao Mori
Abstract
Modulating doping levels and nanofillers blending has facilitated optimization of electrical properties in polymeric nanocomposite films for thermoelectric applications. Herein we report, free-standing flexible films of PANI:CSA/ZnSb polymer nanocomposites, with varying nanofillers ZnSb ratios, to realize charge localization induced enhancement in power factor (≈10 times) and thermopower (≈6 times) within the protonated PANI:CSA. Le Bail refinement of the XRD pattern reveals lattice expansion and reoriented chain conformation in the pseudo-orthorhombic PANI structure due to ZnSb intercalation. The thermopower, enhanced to ≈50 μV/K at room temperature, was tunable due to the suppressed bipolaronic states and associated charge localization, resulting in an improved power factor of ≈10 μW/m·K 2 . The synthesized polymeric films exhibit excellent mechanical durability, retaining ∼90 % of their electrical conductivity after 2000 bending cycles. A flexible thermoelectric generator (FTEG) fabricated using six PANI:CSA/70 wt% ZnSb films produced an output voltage of ∼0.9 mV on a human wrist and ∼6.7 mV under a temperature gradient of ∼50 K, highlighting prospects of charge localization in improving the low and smeared Seebeck response in conducting polymers like PANI and their potential for wearable thermoelectric energy harvesting applications.