Pozov Sergey M, Ioakeimidis Apostolos, Papadas Ioannis T, Sun Chen, Chrusou Alexandra Z, Bradley Donal D C, Choulis Stelios A
Molecular Electronics and Photonics Research Unit, Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, Limassol 3603, Cyprus.
Department of Physics, Clarendon Laboratory, University of Oxford, Parks Rd, Oxford OX1 3PU, UK.
Materials (Basel). 2020 Nov 11;13(22):5082. doi: 10.3390/ma13225082.
The performance of solution-processed organic light emitting diodes (OLEDs) is often limited by non-uniform contacts. In this work, we introduce Ni-containing solution-processed metal oxide (MO) interfacial layers inserted between indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to improve the bottom electrode contact for OLEDs using the poly(p-phenylene vinylene) (PPV) derivative Super-Yellow (SY) as an emission layer. For ITO/Ni-containing MO/PEDOT:PSS bottom electrode structures we show enhanced wetting properties that result in an improved OLED device efficiency. Best performance is achieved using a Cu-Li co-doped spinel nickel cobaltite [(Cu-Li):NiCoO], for which the current efficiency and luminous efficacy of SY OLEDs increased, respectively, by 12% and 11% from the values obtained for standard devices without a Ni-containing MO interface modification between ITO and PEDOT:PSS. The enhanced performance was attributed to the improved morphology of PEDOT:PSS, which consequently increased the hole injection capability of the optimized ITO/(Cu-Li):NiCoO/PEDOT:PSS electrode.
溶液处理的有机发光二极管（OLED）的性能常常受到非均匀接触的限制。在这项工作中，我们引入了含镍的溶液处理金属氧化物（MO）界面层，将其插入氧化铟锡（ITO）和聚（3,4 - 乙撑二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT:PSS）之间，以改善使用聚对苯撑乙烯（PPV）衍生物超黄（SY）作为发光层的OLED的底部电极接触。对于ITO/含镍MO/PEDOT:PSS底部电极结构，我们展示了增强的润湿性，这导致OLED器件效率得到提高。使用铜锂共掺杂的尖晶石镍钴矿[(Cu - Li):NiCoO]可实现最佳性能, 对于这种材料，SY OLED的电流效率和发光效率分别比在ITO和PEDOT:PSS之间没有含镍MO界面改性的标准器件所获得的值提高了12%和11%。性能的提高归因于PEDOT:PSS形态的改善，这相应地提高了优化后的ITO/(Cu - Li):NiCoO/PEDOT:PSS电极的空穴注入能力。
