Influence of structure phase transition on the thermoelectric properties of Cu2Se1- x Te x liquid-like compounds

Trung Kien Mac; Thi Thu Ta; Huu Tuan Nguyen; Van Du Nguyen; Thi Lan Huong Pham; Van Thiet Duong; Tran Dang Thanh; Bach Thang Phan; Anh Tuan Duong

doi:10.1039/d2ra04268a

Influence of structure phase transition on the thermoelectric properties of Cu₂Se_{1- x} Te _x liquid-like compounds

RSC Adv. 2022 Sep 15;12(40):26383-26389. doi: 10.1039/d2ra04268a. eCollection 2022 Sep 12.

Authors

Trung Kien Mac^{1

2}, Thi Thu Ta^{1

2}, Huu Tuan Nguyen^{2

3}, Van Du Nguyen¹, Thi Lan Huong Pham⁴, Van Thiet Duong⁵, Tran Dang Thanh^{5

6}, Bach Thang Phan⁷, Anh Tuan Duong^{1

2}

Affiliations

¹ Faculty of Materials Science and Engineering, Phenikaa University Yen Nghia, Ha-Dong District Hanoi 12116 Vietnam tuan.duonganh@phenikaa-uni.edu.vn.
² Phenikaa Research and Technology Institute (PRATI), A&A Green Phoenix Group 167 Hoang Ngan Hanoi 10000 Vietnam.
³ Faculty of Electrical and Electronic Engineering, Phenikaa University Hanoi 12116 Vietnam.
⁴ Faculty of Biotechnology, Chemistry and Environmental Engineering, Phenikaa University Hanoi 10000 Vietnam.
⁵ Graduate University of Science and Technology, Vietnam Academy of Science and Technology 18-Hoang Quoc Viet, Cau Giay Hanoi 10000 Vietnam.
⁶ Institute of Materials Science, Vietnam Academy of Science and Technology 18-Hoang Quoc Viet, Cau Giay Hanoi 10000 Vietnam.
⁷ Center for Innovative Materials and Architectures, Vietnam National University Ho Chi Minh City Vietnam.

Abstract

Copper chalcogenide Cu₂(Se,Te) compounds are well known as typical p-type thermoelectric materials with a figure of merit (ZT) that can be optimized by the ratio of Se : Te. Here, by using the mechanical alloying and solid-state reaction methods, Te was substituted into Se sites within Cu₂Se as the formula Cu₂Se_1-x Te _x (x = 0.1, 0.2, 0.25, and 0.3). The observed changes in structural phase, grain morphologies, and grain size were recorded by XRD and FE-SEM imaging with the appearance of the secondary phase of Cu₂Te, with a Te content of x = 0.25. The layered structure morphology was observed more clearly at the high Te content. The electrical conductivity was greatly increased with enriched Te content while the maximum Seebeck coefficient was obtained in the Cu₂Se_0.75Te_0.25 sample. Accordingly, a power factor value of up to 9.84 μW cm^-1 K^-2 at 773 K was achieved. The appearance of a Cu₂Te phase with a Te content of 0.25 created a structural phase transition which results in a ZT value of 1.35 at 773 K in the Cu₂Se_0.75Te_0.25 sample.