High Thermoelectric Performance of Cu₃SbSe₄ Obtained by Synergistic Modulation of Power Factor and Thermal Conductivity

Abstract

In this work, Cu 3−y Ag y Sb 1−x Ge x Se 4 (x = 0, 0.04, 0.06, 0.08, 0.10, 0.12; y = 0, 0.1, 0.2, 0.3, 0.4) is fabricated using a high-temperature melting process, and the thermoelectric properties are investigated in the temperature range of 300−700 K. As a result, a remarkable improvement in thermoelectric performance of Cu-based ternary thermoelectric materials is achieved here. Ge doping increases the carrier concentration leading to a decrease in electrical resistivity; Ag alloying can reduce thermal conductivity significantly and enhance the power factor. Consequently, a maximum figure of merit, 0.95, is obtained for Cu 2.7 Ag 0.3 Sb 0.94 Ge 0.06 Se 4 and Cu 2.6 Ag 0.4 Sb 0.94 Ge 0.06 Se 4 at 700 K, which is higher than most reported Cu 3 SbSe 4 -based systems.

Copper-Based Diamond-like Thermoelectric Compounds: Looking Back and Stepping Forward

“…The Cu 3 SbSe 4 diamond-like compound with a small bandgap is also an example influenced by the strong relativistic orbital-contraction effect [164,165]. Softening p-d hybridization, as an active strategy, has been adopted to synergistically improve the electronic and thermal transport performance of Cu 3 SbSe 4 via Ag-doping [49,166], as shown in Figure 7b. Zhang et al [49] discovered that the PF of Cu 3 SbSe 4 was significantly enhanced by changes in the bandgap and the density of states caused by the softening of p-d hybridization, which, accompanied by Ag-doping, induced large strain fluctuations in some local structural distortions and resulted in greatly reduced κ L .…”

Enhanced near-room temperature thermoelectric performance and mechanical strength of n-type BiTeSe materials incorporated with Ag2Se inclusions

“…However, these thermoelectric parameters (S, σ and κ) are intertwined, which remains a challenge for improving ZT. [10][11][12][13][14][15][16][17] Bi 2 Te 3 -based materials are the most successful commercial TE materials and have been used in TE coolers. They also have potential applications as TE generators for low-grade heat sources.…”

“…However, these thermoelectric parameters ( S , σ and κ ) are intertwined, which remains a challenge for improving ZT. 10–17…”

Inducing High Power Factor in Cu2GeSe3-Based Bulk Materials via (Bi, Zn)-Co-doping

“…Therefore, a larger PF ave value is more suitable for obtaining a higher output power in practical applications . In the past decades, a number of methods were carried out to increase the PF and PF ave , including adjusting the carrier concentration ( n ) and optimization of electronic band engineering, which were mainly achieved by doping. − …”