用光伏效应研究有机薄膜电致发光器件中的接触性质

首次发现了有机薄膜电致发光器件的光生伏特效应，通过对器件的光电流响应谱的详细研究，分析了不同结构的有机发光器件中的有机半导体之间，以及有机半导体与电极材料之间的半导体接触性质，发现有机发光材料Ａｌｑ３，有机空穴传输材料ｄａｉｍｉｎｅ与金属铝电极之间形成阻挡接触，是电致发光器件发光和产生光电效应的根本原因；而双层器件中有机层Ａｌｑ３与ｄｉａｍｉｎｅ之间的结是双层器件产生高发光效率的原因，正是这种结在双层器件中起了局限载流子和激子的作用，使发光亮度大为提高，结合分区掺杂实验结果，给出了较完善的能带模型．

THE INVESTIGATION OF SEMICONDUCTOR CONTACT IN ORGANIC ELECTROLUMINESCENT DEVICE WITH PHOTOVOLTAIC METHOD

hotovoltaic properties of single and double layer structural organic thin film electroluminescent devices have been firstly reported. The polarity of photovoltaic indicated that the photovoltaic effect was Schottky effect. And different semiconductor contactsbetween different organic semiconductors or organic materials and electrodes of the devices have been given by analysing the action spectra of pbotocurrent of devices. In thesingle layer device(ITO/Alq3/Al),the photocurrent was generated from Alq3/Al interface, which implied that there was a Schottky barrier here. For double layer device (ITO/diamine/Alq3/Al), the photocurrent was generated from both Alq3/Al and diamine/Alq3 interfaces. This comfirmed that a p-n junction exists at the interface of diamine/Alq3, which had been assumed in prior paper. It is the p-n junction that confines the carriers and the excitons in a narrow luminessent layer and increases the EL efficiency and brightness in double layer device. Energy band models were proposed to explain the photovoltaic behaviors and the EL charactoristics of the devices.