Theoretical Study of Interfacial and Electronic Properties of Transition Metal Dichalcogenides and Organic Molecules Based van der Waals Heterostructures

Heterostructures built from 2D materials and organic semiconductors offer a unique platform for addressing many fundamental physics and construction of functional devices. Interfaces play a crucial role in tailoring the heterostructure properties. Here, density functional theory computations are performed to explore the interfacial properties of heterostructures made of group VI transition metal dichalcogenides (TMD) and organic molecules such as perylene tetracarboxylic dianhydride (PTCDA) and pentacene. First principle calculations predict that the organic pentacene layer exhibits covalent interfacing with MoSe2 and WSe2, while the interface of other studied TMD/organic heterostructures form van der Waals (vdW) interfaces. Owing to the different molecular geometry of PTCDA and pentacene in their respective heterostructures, the work function can be modulated of the order of 1.0 eV in comparison with pure monolayer MX2 in MX2/pentacene (M = Mo, W; X = S, Se) heterostructures, while the change of work function in MX2/PTCDA (M = Mo, W; X = S, Se) is negligible (order of 0.1 eV) in comparison with pure monolayer MX2. This study will be helpful to design high-performance optoelectronic devices based on TMDs and organic semiconductors.