Photoemission of Some Organic Donor–Acceptor Complexes

Abstract

Photoemissive thresholds were determined of a number of donor–acceptor complexes (tetramethyl-p-phenylenediamine and p-phenylenediamine as donors with chloranil and bromanil as acceptors) by extrapolation of the wavelength-vs-photocurrent curves to zero current. These thresholds were compared with those of the constituent components. The thresholds of the complexes are found to be somewhat higher than those of the donors (by about 0.1–0.2 eV) and also the behavior of the wavelength-vs-photocurrent curves near the threshold appears to be different. The observed phenomena are consistent with a model in which the lattice of a donor–acceptor complex contains neutral molecules as well as ions.