Effect of doping on optical and transport properties of charge carriers in Alq3

We investigated the optical and transport properties of charge carriers in doped amorphous Tris (8-hydroxyquinolinato) aluminum (Alq3) films from room temperature to 130 °C. The doping concentration of dopant DCM was up to 24 wt% in Alq3 films. The current–voltage, electroluminescence (EL) and light–current characteristics were measured. The current density was sharply increased up to a DCM concentration of 1.5 wt% in Alq3 films for the same bias voltage. The EL peak position shifted from green to red color with DCM doping concentration in Alq3. The highest EL efficiency was found for a DCM doping concentration of 0.5 wt%. The EL intensity was increased by about 2.5 times than that of the pure Alq3. The EL intensity was reduced with temperature.