Materials Institute, The Scientific and Technological Research Council of Turkey (TUBITAK)-Marmara Research Center (MAM), Gebze/Kocaeli, 41470, Turkey.
Department of Physics, Gebze Technical University, Gebze/Kocaeli 41400, Turkey.
Nanotechnology. 2017 Jun 16;28(24):245204. doi: 10.1088/1361-6528/aa6f55. Epub 2017 Apr 25.
The electrode/organic interface is one of the key factors in attaining superior device performance in organic electronics, and inserting a tailor-made layer can dramatically modify its properties. The use of nano-composite (NC) materials leads to many advantages by combining materials with the objective of obtaining a desirable combination of properties. In this context, zinc oxide/polyethyleneimine (ZnO:PEI) NC film was incorporated as an interfacial layer into inverted bottom-emission organic light emitting diodes (IBOLEDs) and fully optimized. For orange-red emissive MEH-PPV based IBOLEDs, a high power efficiency of 6.1 lm W at a luminance of 1000 cd m has been achieved. Notably, the external quantum efficiency (EQE) increased from 0.1 to 4.8% and the current efficiency (CE) increased from 0.2 to 8.7 cd A with rise in luminance (L) from 1000 to above 10 000 cd m levels when compared to that of pristine ZnO-based devices. An identical device architecture containing a ZnO:PEI NC layer has also been used to successfully fabricate green and blue emissive IBOLEDs. The significant enhancement in the inverted device performance, in terms of luminance and efficiency, is attributed to a good energy-level alignment between the cathode/organic interface which leads to effective carrier balance, resulting in efficient radiative-recombination.
电极/有机界面是获得有机电子学优异器件性能的关键因素之一，插入定制层可以显著改变其性质。通过将具有目标性质的材料组合在一起使用纳米复合材料（NC）材料，可以带来许多优势。在这种情况下，将氧化锌/聚乙烯亚胺（ZnO：PEI）NC 薄膜作为界面层并入倒置底发射有机发光二极管（IBOLED）中，并进行了全面优化。对于基于 MEH-PPV 的橙红色发射 IBOLED，在亮度为 1000 cd/m 时实现了 6.1 lm W 的高光功率效率。值得注意的是，与原始 ZnO 基器件相比，当亮度从 1000 cd/m 升高到 10000 cd/m 以上时，外量子效率（EQE）从 0.1%提高到 4.8%，电流效率（CE）从 0.2 cd/A 提高到 8.7 cd/A。含有 ZnO：PEI NC 层的相同器件结构也成功地制备了绿色和蓝色发射 IBOLED。倒置器件性能在亮度和效率方面的显著提高归因于阴极/有机界面之间的良好能级对准，这导致有效的载流子平衡，从而实现有效的辐射复合。
