Nanohybrids of 2D Black Phosphorus with Phthalocyanines: Role of Interfacial Interactions in Heterostructure Development

New 2D black phosphorus (bP)-phthalocyanine (Pc) nanohybrids have been synthesized by liquid phase exfoliation of black phosphorus crystals in the presence of two organic dyes: phthalocyanine (Pc) and manganese phthalocyanine (MnPc). The key role of the metal cation in the interfacial interaction between the organic dye and bP nanosheets was demonstrated by X-ray absorption spectroscopy and associated with an electron transfer between the metal cation Mn2+ and bP nanosheets, which resembles a coordinative chemical bond. On the other hand, the interaction between bP nanosheets and pure phthalocyanine is governed by van der Waals forces. The fluorescence of both hybrids is significantly reduced indicating effective separation of the photoinduced charge, implying the formation of a heterojunction between the organic molecules and the bP nanosheets. These findings provide important insights into the interfacial interactions in bP-Pc nanohybrids that are relevant for application in 2D organic/inorganic devices.