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 Bi2O2 Se 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 Bi 2O2Se through both experimental measurements and theoretical calculations. It is found that the post-growth 2D Bi2O2 Se 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 Bi 2O2Se (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 Bi 2O2Se, but also provide a general and alternative strategy of vacancy engineering for tuning the thermoelectric properties of low-dimensional materials.