Enhanced thermoelectric properties of highly textured Bi2O2-xSe1+x with liquid-phase mechanical exfoliation

In the present work, an artificial designed composition defects coupled with liquid-phase mechanical exfoliation (LME) was introduced to improve the thermoelectric performance of Bi2O2Se. The results indicate that non-stoichiometric of Bi2O2Se with LME could induce high grain orientation. Moreover, the electrical conductivity of Bi2O2-xSe1+x with LME have been greatly improved due to both higher carrier concentration and holes mobility. In contrast, a relatively low thermal conductivity had been retained. Finally, A high ZT(peak) of around 0.54 at 773 K was obtained for the sample Bi2O1.96Se1.04 with LME, which is a new ZT record of Bi2O2Se based thermoelectrics. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.