【摘要】 含吡啶基的二唑类材料 (PDPyDP)作为一种新型的电子传输层被有效地应用于可溶性聚对苯乙炔(MEH PPV)为发光层的双层结构的有机发光二极管器件中 ,并将其光电性能与MEH PPV的单层结构器件及分别含苯环 (PDPDP)和反 1 ,2 亚乙烯基 (PDVDP)的另外两种二唑类电子传输层的双层结构器件进行比较。EL光谱测量表明 ,它们的发光均来自于MEH PPV层 ,而它们相似的器件电流和光输出随驱动电场变化的规律表明这些器件中相似的电荷转移过程 ,但电致发光阈值电场对于双层结构器件来说低于单层结构器件 ,而插入PDPyDP层的器件 ,其阈值电场最低。在电流密度为 5 0mA/cm2 时 ,单层器件及各插入PDVDP、PDPDP和PDPyDP的双层器件的外量子效率相对值分别为 3× 1 0 -3 % ,5× 1 0 -3 % ,2× 1 0 -2 %和 0 1 %。并分析了插入PDPyDP使器件发光性能提高最为明显的原因。通过将此类器件的结构等作进一步优化 ,其最佳量子效率可高达 1 4 4%。更多还原

【Abstract】 In this paper we focus on a new type of bis(1,3,4-oxadiazole)system and electron transportingmaterial-2,5-bis[2-(4-tert-buty/pheny/-1,3,4-oxadiazole-5-y1)]pyridine(PDPyDP).We have fabricated organic light-emitting diodes(OLED)using poly[2-methoxy-5-(2-ethy/hexoxy-1,4-pheny/ene)](MEH-PPV),ITO and aluminium as the light emitting layer,anode and cathode;with and without a thermallyevaporated electron transport layer of either PDPyDP or its vinylene analog 1,2-bis[2-(4-tert-buty/pheny)-1,3,4 oxadiazole-y1]benzene(PDPDP). PDPDP is the pare isomer of OXD-7,which is a widely used electron transporting material. Electroluminescence spectra for all devices indicate that light originates only from the MEH-PPV layer.The three bilayer structure devices possess almost identical current versus electric field data ,suggesting a similar electrical transport process in each device. The lowest value of the turn-on electric field for EL has been observed for the OLED incorporating PDPyDP. At a current density of 50mA/cm 2,the values of external quantum efficiency were 3×10 -3% for the MEH-PPV single layer device,5×10 -3% for the bilayer device using PDVDP,2×10 -2% for the PDPDP-containing structure and 0.1% for the OLED incorporating PDPyDP. The reason of the above different EQE was analysed. It is worth noting that further improvement in the efficiency figures is possible by optimizing the device structure and material for the OLED incorporating PDPyDP.The calibrated quantum efficiency for ITO/PEDOT/MEH-PPV∶Rubrene/Al device is 1.44%.更多还原