M. Raikh et X. Wei, CURRENT-VOLTAGE CHARACTERISTICS OF POLYMER LIGHT-EMITTING DIODE AT LOW VOLTAGES, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 256, 1994, pp. 563-569
We argue that the passage of current through a polymer light-emitting
diode at low applied voltages U < 10V is dominated by a sequential tun
neling of electrons (holes) from a contact into the states of the cond
uction (valence) band via the chains of localized states in the gap. T
he current-voltage characteristics I(U), determined by such a mechanis
m, is predicted to be \1nI\alpha 1/root U.