Tuning power factors of two-dimensional Bi2O2Se nanoplates through vacancy engineering

Abstract

Bi2O2Se, as a novel two-dimensional (2D) material, is attracting much attention owing to unique electrical and optoelectrical properties. Particularly, 2D Bi2O2Se with high mobility and a suitable bandgap has been predicted to be a promising thermoelectric material. Here, we performed systematic investigation of thermoelectric properties of 2D Bi2O2Se through both experimental measurements and theoretical calculations. It is found that the post-growth 2D Bi2O2Se nanoplates exhibit semi-metallic behavior because of existence of oxygen vacancies. Furthermore, vacancy engineering through annealing, which effectively tunes the concentration of oxygen vacancies, can significantly enhance the Seebeck coefficient of 2D Bi2O2Se (30–90 μV/K) and the power factor (1–2.7 μW/cm/K2), competitive as an air-stable oxide thermoelectric material. Our results not only demonstrate the promising power factor of 2D Bi2O2Se, but also provide a general and alternative strategy of vacancy engineering for tuning the thermoelectric properties of low-dimensional materials.