摘要
Both single-layer and double-layer organic light-emitting devices based on tris-(8-hydroxylquinoline)-aluminum(Alq3) as emitter are fabricated by thermal vacuum deposition.The electroluminescent characteristics of these devices at various temperatures are measured,and the temperature characteristics of device performance are studied.The effect of temperature on device current conduction regime is analyzed in detail.The results show that the current-voltage(I-V) characteristics of devices are in good agreement with the theoretical prediction of trapped charge limited current(TCLC).In addition,both the charge carrier mobility and charge carrier concentration in the organic layer increase with the rise of temperature,which results in the monotonous increase of Alq3 device current.The current conduction mechanisms of two devices at different temperatures are identical,but the exponent m in current-voltage equation changes randomly with temperature.The device luminance increases slightly and the efficiency decreases monotonously due to the aging of Alq3 luminescent properties caused by high temperature.A tiny blue shift can be observed in the electroluminescent(EL) spectra as the temperature increases,and the reduction of device monochromaticity is caused by the intrinsic characteristics of organic semiconductor energy levels.
Both single-layer and double-layer organic light-emitting devices based on tris-（8-hydroxylquino- line）-aluminum （AIq3） as emitter are fabricated by thermal vacuum deposition. The electroluminescent characteristica of these devices at various temperatures are measured, and the temperature characteristics of device performance are studied. The effect of temperature on device current conduction regime is analyzed in detail. The results show that the current-voltage （I-V） characteristics of devices are in good agreement with the theoretical prediction of trapped charge limited current （TCLC）. In addition, both the charge carrier mobility and charge carrier concentration in the organic layer increase with the rise of temperature, which results in the monotonous increase of AIq3 device current. The current conduction mechanisms of two devices at different temperatures are identical, but the exponent m in current-voltage equation changes randomly with temperature. The device luminance increases slightly and the efficiency decreases monotonously due to the aging of AIq3 luminescent properties caused by high temperature. A tiny blue shift can be observed in the electroluminescent （EL） spectra as the temperature increases, and the reduction of device monochromaticity is caused by the intrinsic characteristics of organic semiconductor energy levels.
基金
Supported partially by the National Natural Science Foundation of China (Grant No. 60425101)
Program for New Century Excellent Talents in University (Grant No. 06-0812)
the Excellent Young Scholars Program of University of Electronic Science and Technology of China (Grant No. 060206)
关键词
有机发光二极管
温度
载流子活性
三-(8-羟基喹啉)铝
organic light-emitting device, temperature, charge carrier mobility, current conduction regime, Alq3
