Embedded in-situ nanodomains from chemical composition fluctuation in thermoelectric A2Cu3In3Te8 (A = Zn, Cd)

Complex diamond-like chalcogenides , A 2 Cu 3 In 3 Te 8 (A = Zn, Cd, Mn, Mg), were discovered and demonstrated to be promising thermoelectric materials in our prior work. Here we disclose that in-situ nanodomains coherently embedded in the A 2 Cu 3 In 3 Te 8 (A = Zn, Cd) matrixes are generated by the chemical composition fluctuation. Cations enter into the interstitial lattice sites to form in-situ nanodomains, which slightly influence electron migration but effectively scatter phonons . The nanodomains can be successfully tailored by further composition fluctuation with the substitution of Cu + for A 2+ , resulting in significantly improved electrical transport properties and reduced lattice thermal conductivity . The peak zT values of ∼1.0 and 1.2 at 873 K are achieved for Zn 1.6 Cu 3.4 In 3 Te 8 and Cd 1.6 Cu 3.4 In 3 Te 8 , respectively, exceeding the hitherto reported zT values among quaternary diamond-like chalcogenides. Manipulating in-situ nanodomains in A 2 Cu 3 In 3 Te 8 by introducing chemical composition fluctuation renders a promise in enhancing thermoelectric efficiency by nanostructure engineering within the complex thermoelectric materials.