Engineering intermediate band states in Cu-intercalated 2D transition metal chalcogenides

Intercalated layered transition metal chalcogenides and metal atom hybrids have been shown to have remarkable properties with a high degree of tunability. Herein, we have studied the optoelectric properties of hybrid structures derived from Cu-intercalated atomically thin GeSe/SnS heterostructures. Using the Green's function and Coulomb interaction and Bethe-Salpeter equation approaches, we determined the single-particle electronic and two-particle absorption properties. In the hybrid materials, we find intermediate band (IB) states with subband gap values of 0.78 and 1.26 eV, which are remarkably close to the subband gaps (~0.71 and 1.24 eV) for IB solar cell materials predicted by the Luque-Marti model.