Alq₃ 두께 변화에 따른 유기 발광 소자의 내장 전압

Abstract

Built-in voltage in ITO/Alq₃/Al organic light-emitting diodes was studied by varying a thickness of Alq₃ layer using modulated photocurrent technique at ambient condition. A thickness of the Alq₃ layer was varied from 100 to 250 nm. From the bias voltage-dependent photocurrent, built-in voltage of the device was able to be determined. The obtained built-in voltage is about 0.8 V irrespective of the Alq₃ layer thickness in the device. This value of built-in voltage confirms that the built-in voltage is generated due to a difference of work function of the anode and cathode. The Alq3 layer thickness independent built-in voltage indicates that the built-in electric field in the device is uniform across the organic layer.