Boosting the thermoelectric performance of zinc blende-like Cu2SnSe3 through phase structure and band structure regulations. Issue 24 (6th June 2022)

• Record Type: Journal Article
• Authors: Wang, Meng; He, Mingkai; Zhu, Lujun; Ma, Baopeng; Zhang, Fudong; Liang, Pengfei; Chao, Xiaolian; Yang, Zupei; He, Jiaqing; Wu, Di
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 24(2022)
• Page Start: 12946
• Page End: 12956
• Publication Date: 2022-06-06
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta02888c
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Phase transition from the (cation) ordered δ-phase to the disordered cubic phase upon In/Sb co-doping leading to a significantly enhanced thermoelectric performance in zinc blende-like Cu2 SnSe3 . Abstract : As a variant of the zinc blende structure, p-type semiconducting Cu2 SnSe3 exhibits a high potential in the field of thermoelectric energy conversion, due to the low lattice thermal conductivity and large abundance of the constituent elements. Till now, the bottleneck of achieving a comparable thermoelectric performance in Cu2 SnSe3 with state-of-the-art thermoelectric material systems is its unsatisfactory electrical power factor. In this work, we realized a simultaneous increment of charge carrier concentration and mobility through In/Sb co-doping at the Sn site; detailed X-ray diffraction (XRD), Rietveld refinement, and density functional theory (DFT) band structure calculations revealed a gradual phase structure (and an associated band structure) transition from a low-symmetry monoclinic phase to a high-symmetry cubic one, which was further verified by Cs-corrected scanning transmission electron microscopy (Cs-corrected STEM) characterization. Eventually, we achieved a peak figure of merit, ZT max ∼0.90 at 773 K and an average ZT avg ∼0.36 (323–773 K) for the composition of Cu2 (Sn0.85 In0.05 Sb0.05 Ti0.05 )Se3, representing the state of the art for all Cu2 SnSe3 -based thermoelectric materials reported thus far.