Enhanced Thermoelectric Properties and Flexibility of 2D Bi₂Si₂Te₆ Nanosheets and PEDOT:PSS-Based Thermoelectric Composites

Herein, dimethyl sulfoxide (DMSO)-treated Bi 2 Si 2 Te 6 nanosheet (NS)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) composite films with enhanced thermoelectric (TE) properties and flexibility are prepared. First, the Bi 2 Si 2 Te 6 NSs for use as inorganic fillers are manufactured via a hydrothermal reaction to intercalate lithium, followed by exfoliation. The as-fabricated Bi 2 Si 2 Te 6 NS are then dispersed into the PEDOT:PSS, and Bi 2 Si 2 Te 6 NS/PEDOT:PSS composite films are fabricated via a drop-casting method. The as-synthesized Bi 2 Si 2 Te 6 NS/PEDOT:PSS composite shows an enhanced power factor due to the outstanding electrical conductivity and Seebeck coefficient of the Bi 2 Si 2 Te 6 NSs. Specifically, the composite film with 50 wt % Bi 2 Si 2 Te 6 NSs shows a maximum power factor of ∼140.4 μW/m·K 2 . Furthermore, the electrical conductivity of the Bi 2 Si 2 Te 6 NS/PEDOT:PSS composite was improved via post-synthetic treatment with DMSO. An enhanced power factor of ∼164.1 μW/m·K 2 was reached by using 50 wt % Bi 2 Si 2 Te 6 NS and 5 vol % of DMSO. The as-prepared TE composite is expected to provide an important component for flexible organic/inorganic hybrid materials with enhanced TE performance.