Enhanced thermoelectric performance of a simple method prepared polycrystalline SnSe optimized by spark plasma sintering

Abstract

In this study, polycrystalline SnSe was synthesized via a rapid, cost-effective, and large-scale synthesis route. The obtained SnSe powders were pressed into pellets via spark plasma sintering (SPS) at different temperatures. Powder X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) were used to characterize the crystal structures and morphology of the SnSe samples. The XRD results indicate that the orientation factors increase monotonously with the increase of sintering temperature. The FESEM images show that sintering temperatures have no obvious influence on the particle size. Positron annihilation measurements indicate that vacancy defects exist in all the sintered SnSe samples, and they recover gradually with increasing sintering temperatures. These vacancy defects are responsible for the lower lattice thermal conductivity in samples sintered at lower temperatures. The electrical conductivity, power factor, thermal conductivity, and figure of merit ZT show nearly the same variation trend, which increases initially with the increasing sintering temperature up to 550 °C then decreases with further increase of the sintering temperature, which is possibly due to slight oxidation of SnSe. A maximum ZT value of ∼0.47 at 430 °C was achieved for the 550 °C sintered sample, which is higher than those reported for undoped polycrystalline SnSe around this temperature. Thus, we provide a simple, energy-saving, and effective method to synthesize polycrystalline SnSe in large quantities, and SPS is an effective method to optimize thermoelectric performance.

Tin-selenide as a futuristic material: properties and applications

“…119 The thermoelectric parameters of poly-crystals SnSe are tuned by sintering temperature in the spark plasma sintering (SPS). Zhang et al 120 varied the sintering temperature from 300 to 650 C in SPS and showed that vacancy defects (Se, Sn, and Se-Sn) were responsible for the performance variation. The optimized sintering temperature for the best performance of the material was 550 C. The ZT of 0.47 was observed at 430 C. Ge alloying's effect was studied by varying Ge concentration in the range x ¼ 0.01 to 0.03 (Sn 1Àx Ge x Se).…”

“… 119 The thermoelectric parameters of poly-crystals SnSe are tuned by sintering temperature in the spark plasma sintering (SPS). Zhang et al 120 varied the sintering temperature from 300 to 650 °C in SPS and showed that vacancy defects (Se, Sn, and Se–Sn) were responsible for the performance variation.…”

Cold Sintering Mediated Engineering of Polycrystalline SnSe with High Thermoelectric Efficiency

“…(h) Detailed XRD patterns between 28° and 32° in (g). (i) F value of bulk samples in this work and the previous studies. − …”

Giant Reduction in the Thermal Conductivity of Porous β-Ga2O3 with Multiple Heat-Blocking Mechanisms

“…The variations on the microscopic defects including the defect size and relative concentration in the sample can be detected by positron annihilation spectroscopy. ,, Figure S1 in the Supporting Information shows the peak-normalized positron lifetime spectra of GO-600 and GO-1200. The spectrum of GO-600 shows a longer tail than that of GO-1200, suggesting that there are abundant nanopores in GO-600, which is consistent with nitrogen adsorption/desorption isotherms and SEM results.…”