Excellent visible light absorption and ultra-high photoelectric conversion efficiency of two-dimensional (MoSe2)x(MoSTe)1-x mosaic heterostructures

Solar cells are a promising and potentially sustainable energy technology due to their cost-effectiveness, eco-friendliness, and capacity for integration into pliable apparatuses. Developing new photovoltaic materials to achieve higher photovoltaic conversion efficiency is a hot topic in the field of solar cells. In this work, the electronic structures and optical properties of two-dimensional (MoSe2)x(MoSTe)1-x mosaic heterostructures have been studied by density functional theory. Our results show that the mosaic heterostructures retain semiconductors with tunable band gap of 1.14–1.53 eV. With the augmentation of MoSe2 concentration in the mosaic heterostructures, the band gap of the materials has gradually increased. Besides, the mosaic heterostructures exhibit excellent optical absorption in the visible light region. Furthermore, the maximum theoretical photoelectric conversion efficiency of (MoSe2)0.80(MoSTe)0.20 mosaic heterostructure can reach 32.36 %. The tunable band gap, excellent light absorption, and ultra-high photoelectric conversion efficiency of (MoSe2)x(MoSTe)1-x mosaic heterostructures make them candidates for new nanocrystalline thin-film solar cells.