掺杂有机电致发光中电压调制变色两种机制的探讨  

Two Mechanisms of the Color-tunable Organic Electroluminescence by the Voltage Applied

作　　者：章婷[1] 徐征[1] 陈晓红[1] 沈鸿[1] 刘舒曼[1] 

机构地区：[1]北方交通大学光电子技术研究所,信息存储,显示与材料部级开放实验室,北京100044

出　　处：《光谱学与光谱分析》2002年第6期891-894,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金 (批准号 :2 9992 530 ;1 99740 0 2 ) ;北方交通大学攀登基金

摘　　要：研究两种掺杂电致发光器件聚乙烯基咔唑 (PVK) :Rubrene和Alq3:MN PPV。通过其光致发光及电致发光特性的研究 ,发现两种器件的光致发光与电致发光有较大差别。分析认为这是能量传递及电致发光中陷阱对载流子吸引的共同作用使得PVK激子在光致发光和电致发光中的复合速率不同造成的 ;同时发现对于不同浓度的PVK :Rubrene及Alq3:MN PPV电致发光随电压增加都发生变色现象 ,但是它们分别是由两种不同的机制造成的 :前者作为染料分子Rubrene ,不能形成类似Alq3那样的分相体系 ,Rubrene发光主要来自PVK的能量传递及陷阱电子对PVK空穴的吸引 ;后者是由于分相造成载流子在两相中的迁移不平衡。Two devices structures of ITO/PVK: Rubrene/Al and ITO/Alq(3): MN-PPV/Al were developed. Their characters of photoluminescence and electroluminscence were studied. The result showed that there were great difference between the photoluminescence and electroluminscence at a doping ratio of 2wt % in ITO/PVK: Rubrene/Al. It is conluded that energy transfer in these dye-doped devices occurred by Forster energy transfer processes. And the trap effect of electrons of Rubrene on holes of PVK resulted in different combination probability of PVK excitation in photoluminescence and electroluminescence. At the same time, the two EL devices were color-tunable when the bias voltage was increased. The mechanisms which cause color variation are different. In the first device, it indicates that the energy transfer process from PVK to Rubrene is riot complete. The combination probability of PVK excitation which does not contribute to the emmision of Rubrene is increased when the bias voltage increases. But in the second device, there are many micro-interfaces due to the phase-separation just like the interface in a double layer device. The tunneling interface barriers of carriers is the main cause of color variation in the second device.

关 键 词：掺杂 有机电致发光 电压调制变色 有机电致发光器件 能量传递 聚乙烯基咔唑 聚合物 发光机理 Alq3:MN-PPV 

分 类 号：TN383.1[电子电信—物理电子学] O631[理学—高分子化学]