Abstract
We have measured the temperature dependence of electroluminescence in poly(p-phenylene vinylene) (PPV) devices in order to study charge injection across the electrode/polymer interfaces. The devices used were made with an indium tin oxide (ITO) hole injecting contact, and either an aluminium, magnesium, or calcium electron injecting contact. The IV curves show two distinct features. There is a thermally activated process at low fields, followed by field emission at high fields, when light is seen. The thermally activated process is frozen out below ∼200K, and has an activation energy of ∼0.3eV - 0.4eV. These data suggest that the field emission is that of holes across the ITO/PPV interface. The thermally activated process may be space charge limited conduction, in which case the activation energy measured is that of the charge mobility in the polymer. © 1993.
Original language | English (US) |
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Journal | Synthetic Metals |
Volume | 57 |
Issue number | 1 |
DOIs | |
State | Published - Apr 12 1993 |
Externally published | Yes |