Year: 2018
Type: article
Abstract: Thermoelectric energy conversion has attracted much attention as an efficient and environment-friendly energy technology.Thermoelectric energy conversion performance is directly influenced by the figure of merit (ZT) of the thermoelectric material, however, most known thermoelectric materials with high ZT contain toxic and/or scarce elements.Herein, we report the thermoelectric properties of a polycrystalline p-type Si composite.Si is not only one of the most abundant elements in the earth's crust and but also non-toxic.The composite was prepared by consolidating melt-spun B-doped Si ribbons using spark plasma sintering to achieve a nanocrystalline composite.However, unexpectedly, the resulting material was composed of micron-sized grains with submicron-sized pores.This microstructural character provided unexpected benefits from a thermoelectric point of view.First, the mobility of the composite was quite compatible with that of single crystalline B-doped Si wafer, as elucidated by our calculations based on Masseti's formula.Furthermore, the hole concentration was increased in the compound compared to the B-doped Si wafer, due to unintentional Cu-doping during the melt-spinning process, which resulted in enhanced electrical conductivity.Notably, the lattice thermal conductivity was significantly reduced by the existence of pores, while the electrical conductivity was enhanced.This phonon-glass electron-crystal (PGEC), realized in the polycrystalline p-type Si composite, could lead to an increase in ZT.
Source: 대한금속재료학회지
Authors: Ju Hyeong Sun, Young Soo Lim
Institution: Pukyong National University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2890189935