Constructing bulk-contact inside single crystals of organic semiconductors through gel incorporation

Single crystals of organic semiconductors are promising for high-performance semiconducting materials by virtue of their superior charge mobilities. Interfacing these single crystals with other foreign materials is needed to fabricate varied electronic devices. However, it is difficult to construct interfaces inside a single crystal that is typically homogeneous. In this work, single crystals of two typical organic semiconductors, anthracene and 9,10-diphenylanthracene, were grown from both silica gels and phenyl-modified silica gels. X-ray diffraction analysis demonstrated their single crystallinity. Examination of the residues which remained after sublimation of the gel-grown crystals revealed that the single crystals grown from phenyl-modified silica gels incorporated the gel networks, with the gel networks penetrating through the crystal in three-dimensional space, whereas the silica gel-grown crystals did not. This discrepancy suggests that the affinity between the crystal and the gel network favours gel incorporation. As such, our work provides a potential way to fabricate bulk contact between single crystals of organic semiconductors and foreign materials through gel crystallization.