Order–disorder transition and Fano-interference in thermoelectric Cu3SbSe3 nanoparticles

• First experimental Raman Scattering study of thermoelectric Cu3SbSe3.
• Observation of order–disorder transition at 380 K.
• Phonon frequency anomaly across the phase-transition.
• Observation of Fano-interference in the temperature range 80–250 K.
• Signature of negative thermal expansion (NTE) effect.

Temperature dependent Raman scattering measurements were carried out to investigate the phonon behavior of thermoelectric Cu3SbSe3 nanoparticles. The anomalous behavior of phonon mode (Ag) frequency with temperature indicates the possibility of a lattice instability related to the order–disorder structural transition at 380 K. In the low temperature region (80–250 K) we found an asymmetric line shape of Ag mode, which is analyzed and discussed in the light of phonon–continuum Fano-interference effect. We have obtained the thermal conductivity (κ) ∼ 2.04 W/mK at room temperature. The change in thermal conductivity with temperature strongly correlates with the change in total anharmonicity of the Cu3SbSe3 lattice.