Ag-Nanoinclusion-Induced Enhanced Thermoelectric Properties of Ag2S

• Published in: ACS applied energy materials Vol. 2; no. 9; pp. 6383 - 6394
• Main Authors: Tarachand, Mukherjee, Bodhoday, Saxena, Monika, Kuo, Yung-Kang, Okram, Gunadhor Singh, Dam, Siddhartha, Hussain, Shamima, Lakhani, Archana, Deshpande, Uday, Shripathi, Thoudinja
• Format: Journal Article
• Language: English
• Published: American Chemical Society 23.09.2019
• Subjects: thermoelectricity; semiconductor to metal transition; polyol method; ductile Ag2S; nanocomposites; Ag nanoinclusion; Ag2S−Ag; band bending
• ISSN: 2574-0962; 2574-0962
• DOI: 10.1021/acsaem.9b01016

The effects of Ag nanoinclusions on thermoelectric properties of Ag2S semiconducting nanostructures, synthesized by a novel one-pot facile polyol method, have been investigated. The resulting products are characterized by powder XRD, EDAX, XPS, and UV–vis techniques. FESEM images reveal the formation of disc-shaped Ag2S nanoparticles with an average thickness of 52 nm and diameters ranging from 50 nm to a few hundreds of nm. All samples show a systematic reduction in electrical resistivity with increasing Ag content in the composites. The Seebeck coefficient (α) values for the Ag nanoparticle-incorporated Ag2S nanocomposites are notably high near 300 K because of the low-energy charge-carrier filtering effect, which is due to preferential scattering of low-energy electrons at the barrier potentials set up at metal–semiconductor interfaces. The theoretical fitting of α data reveals a systematic shift of the Fermi level toward the conduction band edge with increasing Ag content in the composites. A significantly improved thermoelectric power factor at 325 K is observed for a wide range of Ag nanoinclusions with the highest ZT of 0.0029 at 325 K in the Ag2S–Ag nanocomposite with 20.1% Ag.