Doping Effect of Tetrathianaphthacene Molecule in Organic Semiconductors on Their Interfacial Electronic Structures Studied by UV Photoemission Spectroscopy

Abstract

The n-type doping ability of the electron-donating organic molecule tetrathianaphthacene (TTN) was examined by ultraviolet photoemission spectroscopy (UPS) for two kinds of matrix organic semiconductors, hexadecafluorophthalocyaninatozinc (F 16 ZnPc) and tris(8-hydroxyquinoline)aluminum (Alq 3 ). The observed dependence of the UPS spectra suggests that TTN acts as a good donor in F 16 ZnPc, while the effect was not so significant for Alq 3 . These results and the consideration of the energy parameters of these molecules indicate that a close match between the highest occupied molecular orbital of the dopant and the lowest unoccupied molecular orbital of the matrix is important for efficient n-type doping.