Charge Transfer at the PTCDA/Black Phosphorus Interface

The interfacial electronic structure at the organic–inorganic semiconductor interface plays an important role in determining the electrical and optical performance of organic-based devices. Here, we studied the molecular alignment and electronic structure of thermally deposited 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) molecules on cleaved black phosphorus using photoelectron spectroscopy. The work function of black phosphorus is substantially upped with an organic thin film, originating from the charge transfer from black phosphorus to PTCDA. According to our photoemission spectrum and theoretical simulation, we also define the interaction between PTCDA and black phosphorus as weak van de Waals physisorption, rather than bonding chemisorption. Furthermore, we show that PTCDA thin film can effectively isolate reactive oxygen species, thereby protecting BP surface oxidation and deterioration under ambient conditions. Our results suggest the possibility of manipulating interfacial electronic structures of black phosphorus interface by noncovalent with organic semiconductor, in particular for applications in high-performance organic–inorganic hybrid photovoltaic