Effect of electrical doping on molecular level alignment at organic-organic heterojunctions

The effect of electrical doping on the interface molecular level alignment at organic-organic (OO) heterojunctions is studied with ultraviolet photoemission spectroscopy. Interfaces between hole transport layers (HTL) and electron transport layers are investigated as a function of p doping of the HTLs. Doping induces the formation of an interface dipole with corresponding shift in the relative position of molecular levels across the interface. The modification of the OO electronic structure is believed to be due to the presence of doping-induced excess holes at the interface. (C) 2003 American Institute of Physics.