Proton‐Irradiation Effects on the Thermoelectric Properties of Flexible Bi₂Te₃/PEDOT:PSS Composite Films

Abstract

Abstract Bismuth telluride (Bi 2 Te 3 ) and poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) are two major inorganic and organic thermoelectric (TE) materials that are widely investigated for TE device applications. An inorganic–organic composite, based on Bi 2 Te 3 and PEDOT:PSS possessing a high TE figure of merit, has immense potential in fabricating highly efficient and flexible TE generators. In order to achieve an enhanced TE performance, the interdependent TE parameters such as electrical conductivity and Seebeck coefficient of the composite should be decoupled. In this study, the TE properties of the composites are enhanced through the creation of additional defects in Bi 2 Te 3 via proton irradiation. The structural variations occurred in Bi 2 Te 3 via proton irradiation are analyzed using X‐ray diffraction, X‐ray photoelectron spectroscopy, and transmission electron microscopy, which quantitatively reveal structural damages as well as deviations from the Bi 2 Te 3 stoichiometry. The proton irradiation‐induced antisite defects in the Bi 2 Te 3 crystal are found to be beneficial in decoupling the interdependent TE parameters of Bi 2 Te 3 /PEDOT:PSS composite thin films, through which enhanced TE performance is achieved. The findings demonstrate that proton irradiation of Bi 2 Te 3 is an effective method to engineer the TE properties through inducing defects in Bi 2 Te 3 and enhancing the interaction between Bi 2 Te 3 and PEDOT:PSS.