Doping-mediated stabilization of copper vacancies to promote thermoelectric properties of Cu2−xS. (July 2021)

• Record Type: Journal Article
• Authors: Zhang, Yu; Xing, Congcong; Liu, Yu; Spadaro, Maria Chiara; Wang, Xiang; Li, Mengyao; Xiao, Ke; Zhang, Ting; Guardia, Pablo; Lim, Khak Ho; Moghaddam, Ahmad Ostovari; Llorca, Jordi; Arbiol, Jordi; Ibáñez, Maria; Cabot, Andreu
• Is Part Of: Nano energy. Volume 85(2021)
• Publication Date: 2021-07
• Subjects: Copper sulfide -- Charge transport -- Vacancies -- Thermoelectricity -- Nanocrystal; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2021.105991
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Copper chalcogenides are outstanding thermoelectric materials for applications in the medium-high temperature range. Among different chalcogenides, while Cu2−x Se is characterized by higher thermoelectric figures of merit, Cu2−x S provides advantages in terms of low cost and element abundance. In the present work, we investigate the effect of different dopants to enhance the Cu2−x S performance and also its thermal stability. Among the tested options, Pb-doped Cu2−x S shows the highest improvement in stability against sulfur volatilization. Additionally, Pb incorporation allows tuning charge carrier concentration, which enables a significant improvement of the power factor. We demonstrate here that the introduction of an optimal additive amount of just 0.3% results in a threefold increase of the power factor in the middle-temperature range (500–800 K) and a record dimensionless thermoelectric figure of merit above 2 at 880 K. Graphical Abstract: Small Pb amounts substitute Cu atoms within the Cu1.8 S lattice to create a superstructure that shows improved stability against sulfur volatilization at temperatures up to 880 K, translating into unprecedented thermoelectric figures of merit up to ZT = 2.03. ga1 Highlights: Small dopant amounts prevent sulfur loss from Cu2−x S during heating. Small amounts of Pb significantly improve Cu2−x S power factors. At an optimal dopant concentration, a record ZT = 2.03 is reached.