| 초록 |
A graphene-organic heterointerface was employed to demonstrate anisotropic exciton behavior in crystalline organic semiconductors. A large area, residue-free monolayer graphene served as an atomically thin, transparent and highly conductive epitaxial template for organic crystal growth with specific orientation. A significant enhancement in exciton diffusion length, optical absorption was observed as well as the increment in carrier lifetime. Especially, spectroscopic analysis revealed that the exciton diffusion length increases up to nearly 100 nm in the direction of face-to-face crystallographic plane, which can be attributed to the proximity of adjacent chromophores in such direction. In application to photovoltaic devices, the device yielded 5 times higher power conversion efficiency in comparison to conventional planar heterojunction organic photovoltaic cells. |
