采用真空蒸镀的方法制备了以八羟基喹啉铝(Alq3)为功能层的单层同质结有机电致发光器件,器件结构为indium-tin-oxide(ITO)/tris-(8-hydroxylquinoline)-aluminum(Alq3)x nm)/Mg:Ag。通过改变有机功能层的厚度,采用陷阱电荷限制电流(TCLC)理论对器件电流的数值拟合方法具体地研究了不同薄膜厚度的有机半导体器件内部电流的传导机制,验证了实验结果和理论推导的一致性。结果表明,Alq3层厚度较低的单层器件随外加电压增大,器件电流经历了从欧姆电导区、TCLC区到TCLC-空间电荷限制电流(SCLC)过渡区三个区域的变化;而对于Alq3层厚度较高的单层器件,Alq3层中的陷阱机构增多,导致电流-电压曲线的SCLC区域消失。
Single-layer homojtmctional organic light-emitting diodes based on tris-(8-hydroxylquinoline)-aluminum(Alq3)as emitting layer were fabricated using vacuum deposition method. The device structure is:indium-tin-oxide(ITO)/Alq3(x nm)/Mg: Ag. According to trapped charge limited current(TCLC)theory, the current conduction regime in OLEDs devices with different thin film thicknesses was investigated systematically by varying the thickness.ss of organic functional layer. A fi .fitting analysis of device current via TCLC theory was adopted to study the relationship between experimental data and theoretical prediction. The results demonstrated that the current of single-layer device with Alq3 thin film has a change from ohmic conduction region, TCLC region to TCLC-SCLC transition region; while the current of device with relatively thick film has no SCLC region due to the increase of traps in the Alq3 layer. The numerical fitting is very beneficial for Alq3 film thickness optimization during device fabrication process.