被动驱动有机发光二极管矩阵屏老化性能的研究

Decay Study on a Passive Matrix Organic Light Emitting Diode Display

对102×64点阵的单色被动驱动的有机电致发光(OLED)矩阵屏进行了老化研究。矩阵屏的结构为ITO/CuPc/NPB/Alq3∶C545/LiF/Al。测量了老化前后矩阵屏的电流-电压-亮度曲线,以及电致发光(EL)和光致发光光谱(PL)。比较发现,老化后的器件在同样恒电流的情况下表现出更高的驱动电压,更小的漏电流,以及在阴极和有机层界面上电致发光和光致发光的光谱强度减弱。矩阵屏在老化17 h后,电致发光和光致发光的强度分别降低到初始值的75.6%和81.4%,分析认为,这是因为老化过程中部分发光材料分解,从而造成对矩阵屏的永久损伤。

The decay process of 102 × 64 monochromatic passive matrix organic light-emitting diode （PMOLED） displays is studied. The structure of the device is ITO（ indium tin oxide ）/CuPc（copper pht halocyanine）/NPB（ N, N＇-di （ naphthalene-l-yl ）-N, N＇-diphenyl-benzidine） / Alq3 （ tris-（ 8hydroxyquinoline）aluminum） ： C545 （coumarin）/Alq：3/LiF/Al. Electrical （I-V） and optical characterizations are measured, the EL and PL spectra before and after the aging test are analyzed . The aged device under constant current appeared higher driving voltage, smaller leak current, lower EL and PL intensities which come from the peeling of cathode/organic layers, the burning of shorted routes between the electrodes and the decomposition of light-emitting materials. The EL intensity remains 75.6 % while the PL does 81.4 % of their initials values after 17 h aging, which means the EL and PL decay simultaneously. The decomposition of emissive material is dominant in the decay process and results in the permanent damage in the display panel.