The work entitled “Strong enhancement in phonon scattering through nanoscale grainsin lead sulfide thermoelectrics” was recently published on NPG Asia Materials(IF=9.902, 2013).NPG AsiaMaterials is one Nature research journal, aimed at an audience of scientistsand researchers across the full spectrum of materials research. This is thefirst report in Nature research journal in SUSTC, which is both thefirst-author and corresponding-author affiliate.

       Thermoelectricmaterials that transform waste heat generated by equipment or buildings intoelectricity are emerging as an important green energy technology. Currently,researchers are trying to improve thermoelectric substances by embedding withinthem nanoscale precipitates that allow these materials to capture more heat. Aninternational research group led by Prof. Jiaqing He from the SUSTC has nowdiscovered a way to improve this process by systematically introducingnanoscale crystal structure defects, or ‘nanograins’, into lead sulfide (PbS)particles, Figure (a). Theirapproach tripled the thermoelectric performance of this low-cost mineral fromits bulk state without introducing charge-disrupting centers commonlyassociated with nanoscale precipitates, Figure(b). Detailed analysis revealed that the densely packed nanograins trapheat by scattering solid-state vibrations, or phonons, while simultaneouslysuppressing ‘bipolar’ interactions between charge carriers that can diminishthermoelectric power.

Figure. (a)TEM image for nanograins, the inset is grain-size distribution histogram; (b) Resultof the fit of the theoretical model to the experimental thermal conductivitydata of micro-PbS and nano-PbS.

Link: http://www.nature.com/am/journal/v6/n6/abs/am201439a.html