Strong interlayer coupling mediated giant two-photon absorption in MoSe2/graphene oxide heterostructure: Quenching of exciton bands

A complex few-layer MoSe2/graphene oxide (GO) heterostructure with strong interlayer coupling was prepared by a facile hydrothermal method. In this strongly coupled heterostructure, we demonstrate a giant enhancement of two-photon absorption that is in stark contrast to the reverse saturable absorption of a weakly coupled MoSe2/GO heterostructure and saturable absorption of isolated MoSe2. Spectroscopic evidence of our study indicates that the optical signatures of isolated MoSe2 and GO domains are significantly modified in the heterostructure, displaying a direct coupling of both domains. Furthermore, our first-principles calculations indicate that strong interlayer coupling between the layers dramatically suppresses the MoSe2 excitonic bands. We envision that our findings provide a powerful tool to explore different optical functionalities as a function of interlayer coupling, which may be essential for the development of device technologies.