First-Principles Investigation of the Electronic Properties of 2-D Organic-TMDC Heterostructures

Two-dimensional transition metal dichalcogenides (TMDCs) are considered encouraging materials for photovoltaic applications, with differing electronic and optical properties from their bulk counterparts. Pentacene is an organic compound with high exciton mobility, and complimentary electronic properties to TMDCs. Here are investigated systems of adsorbed pentacene on to monolayers of Group-VI dichalcogenides; MoS2, MoSe2, WS2 and WSe2, for photovoltaic applications. Using ab initio methods within density functional theory, optimized atomic positions were calculated and energetically favourable adsorption sites of pentacene were determined. These sites were further investigated with a varying concentration of adsorbed pentacene, with the aim of investigating how molecule-molecule interactions affect the interaction between molecule and substrate. The electronic properties of the favourable systems were then probed and the charge balance of the systems analysed.