Recently, an undergraduate student, Mingkai He, from Department of Physics, published research results on Applied Physics Letters (listed as one of the Nature Index journals) as first author. The paper, entitled “Excellent Thermoelectric Performance Achieved Over Broad Temperature Plateau in Indium-doped SnTe-AgSbTe2 Alloys”, is about their latest progress on SnTe as a promising thermoelectric material, where another undergraduate student Yingdong Guan participated as the forth author. 

Thermoelectrics ls, which can transfer heat into electricity (or vice versa) without any hazardous byproducts, represents an eco-friendly and sustainable energy conversion technique, thus is believed to have wide application prospects in thermoelectric cooling and waste heat power-generation. However, the relatively low energy conversion efficiency has always been a big issue hindering the commercial application of thermoelectric material. 

SnTe is deemed as a natural candidate to replace the state-of-the-art thermoelectric material PbTe, due to its low-cost, low-toxicity, and mechanical stability. Nevertheless, both the peak and average figure of merits of SnTe currently are way too inferior as compared to PbTe. In this work, the paper report that a peak figure of merit as high as 1.3 can be achieved at 873 K in p-type SnTe when it is simultaneously doped with Indium and alloyed with AgSbTe2. Moreover, the average figure of merit can be lifted astonishingly from 0.244 up to 0.84, by a factor of 344%, which is the record high value ever reported. The enhanced thermoelectric performance comes from a synergetic improvement of the power factor and reduction of lattice thermal conductivity. The method of combining resonant states with alloying may provide inspiration on further research in other thermoelectric materials. 

Mingkai He is an undergraduate student from Department of Physics class of 2014. Ever since his junior second year when he joined Professor Jiaqing He’s research group, under the guidance of Professor He and Research Assistant Professor Di Wu, Mingkai He has demonstrated sound scientific literacy and outstanding research ability. He has conducted most of the experiments in the above-mentioned research independently. The research was supported by Special Fund Program for Guangdong College Student Research & Innovation Cultivation (Climbing Program). 

Source link: http://aip.scitation.org/doi/full/10.1063/1.5018477