Band Engineered I/III/V–VI Binary Metal Selenide/MWCNT/PANI Nanocomposites for Potential Room Temperature Thermoelectric Applications

Room temperature thermoelectric studies are reported herein of ternary hybrids fabricated by ex situ processing involving polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs), and binary metal selenide nanoparticles (MSe NPs) such as CuSe, Ag2Se, In2Se3, and Sb2Se3 synthesized by using cyclohexeno-1,2,3-selenadiazole (SDZ) as selenium precursor. The presence of phase pure MSe NPs in ternary hybrids was confirmed by XRD analysis. FTIR analysis suggested a strong π–π interaction between PANI and MWCNTs. Electrical conductivities, Seebeck coefficients, and power factors of these band engineered ternary nanocomposites were investigated at room temperature. Ag2Se NPs/MWCNT/PANI (ASCP) showed p-type behavior with figure of merit (zT) of 0.012 at room temperature, while other hybrids exhibited n-type behavior. All of the ternary hybrids showed high electrical conductivities, and among n-type hybrids, CuSe NPs/MWCNT/PANI showed the best thermoelectric performance. The present work opens up an efficient approach to enhance the utility of metal chalcogenides as sensitizers in thermoelectric applications. The possible mechanism for charge transport is also discussed.