Hefei Research Institute made progress in optimizing thermoelectric properties of chalcopyrite material system

[ Instrument Network Instrument Development ] Recently, Qin Xiaoying, a researcher at the Institute of Solid State Physics, Hefei Institute of Material Science, Chinese Academy of Sciences, made new progress in thermoelectric material performance research. It was introduced into Cu-type Cu-Cu2 material by p-type 赝 cubic structure by Ag and In alloying. The multi-component domain structure suppresses the phonon transport in the material while significantly enhancing its thermoelectric potential, thereby maintaining a high power factor while greatly reducing the thermal conductivity, and finally its thermoelectric performance is greatly improved, ZT=1.64@873K The highest value has been reported for this system. The results are published online in the journal Advanced Materials.

Thermoelectric devices with thermoelectric materials as the core components can directly convert thermal energy and electrical energy without moving parts, no noise pollution, and no toxic or greenhouse gases. The material system of chalcopyrite structure, CuGaTe2, etc., has attracted much attention due to its high power factor, but its inherently high lattice thermal conductivity limits the further improvement of the thermoelectric performance of the system.

Based on the material system and based on the previous research basis, researchers have prepared a multi-component alloy compound system Cu1-xAgxGa0.4In0.6Te2 with complex nano-sized strain domain structure by introducing isoelectronic elements In and Ag into CuGaTe2 ( 0 ≤ x ≤ 0.4). The nanoscale multi-domain domain structure causes strong phonon scattering (Figures 1, 2), which results in a significant decrease in the thermal conductivity of the optimized compound system. For example, the thermal conductivity at 300 K is 6.1 W from the matrix compound CuGaTe2. • m-1·K-1 drops to 1.5 W·m-1·K-1 of x = 0.4 sample, as shown in Figure 3. Finally, the optimized chalcopyrite sample Cu0.7Ag0.3Ga0.4In0.6Te2 has excellent thermoelectric properties, ZT reached the highest reported value of 1.64 (873K, as shown in Figure 1), and the average ZT reached in the 300-873K temperature range. 0.73, the average value of ZT maximum and temperature (300-873K) of the optimized chalcopyrite compound is increased by about 37% and 35%, respectively, compared with the ZT value of pure phase CuGaTe2, indicating that in this chalcopyrite compound, Alloying by isoelectronic elements and nanoscale domain structures can effectively inhibit thermal conductivity and significantly improve thermoelectric properties. Related work also provides an important reference for the subsequent design and construction of microstructures to improve the thermoelectric performance of other related material systems.

The work was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Anhui Province.