Improved thermoelectric performance of bilayer Bi2O2Se by the band convergence approach

Abstract

Using first-principles calculations combined with Boltzmann transport theory, we investigate the effects of the interlayer distance on the electronic and phonon thermal transport properties of the bilayer Bi₂O₂Se. As the interlayer distance varies from 3.65 to 3.35 Å, the maximum power factors of 13–90 and 10–13 μW cm⁻¹ K⁻² are found for p-type and n-type doped bilayer Bi₂O₂Se, respectively. The figure of merit value of p-type doped bilayer Bi₂O₂Se is enhanced to 1.86 with an interlayer spacing of 3.35 Å at 300 K. At 800 K, it is as high as 5.9, which is much larger than the highest value of 3.35 for Bi₂O₂Se reported in the literature. This study thus demonstrates that structural dimension reduction and band convergence are effective methods for improving the thermoelectric performance of Bi₂O₂Se.