Electric field tunable electronic structures and ultrahigh power conversion efficiency of BC 6 N/MoSe 2 van der Waals heterostructure: A promising material for high-efficiency solar cell applications

A novel BC 6 N/MoSe 2 van der Waals heterostructure (vdWH) was fabricated by stacking monolayer BC 6 N onto monolayer MoSe 2 . The structural stability, electronic structure, optical properties, and power conversion efficiency (PCE) of the BC 6 N/MoSe 2 vdWH were systematically investigated using first -principles calculations and by considering the effects of electric fields. The results indicated that the stable BC 6 N/MoSe 2 vdWH has an indirect band gap of 1.84 eV, and exhibits a type II band alignment which is not affected by external electric fields. Additionally, the band gap of BC 6 N/MoSe 2 decreased linearly with increasing intensity of the electric field, and the maximum band gap was 1.88 eV under an electric field of -0.05 V/& Aring;. The optical absorptivity of the BC 6 N/ MoSe 2 vdWH increased in the visible region, with the highest optical absorptivity (23.1 %) observed in the violet region. The BC 6 N/MoSe 2 vdWH displayed an ultrahigh PCE (22.9 %), which reached 23.6 % under an electric field of -0.05 V/& Aring;. The PCE decreased with increasing intensity of the electric field, but was still high (19.1 %) under an electric field of 0.2 V/& Aring;. The optimal optical absorptivity and ultrahigh and tunable PCE of the BC 6 N/ MoSe 2 vdWH indicate its great potential for application as high -efficiency solar cell materials.