Kim Yejin, Nam Hyuckjin, Ryu Boeun, Son Seo Yeong, Park Seong Yeon, Park Sejung, Youn Sung-Min, Yun Changhun
School of Polymer Science and Engineering, Chonnam National University, Gwangju 61186, Republic of Korea.
Energy & Nano Technology Group, Korea Institute of Industrial Technology, Gwangju 61012, Republic of Korea.
ACS Appl Mater Interfaces. 2024 May 15;16(19):25053-25064. doi: 10.1021/acsami.4c03104. Epub 2024 May 1.
Among various conductive polymers, the poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) film has been studied as a promising material for use as a transparent electrode and a hole-injecting layer in organic optoelectronic devices. Due to the increasing demand for the low-cost fabrication of organic light-emitting diodes (OLEDs), PEDOT:PSS has been employed as the top electrode by using the coating or lamination method. Herein, a facile method is reported for the fabrication of highly efficient polymer light-emitting diodes (PLEDs) based on a laminated transparent electrode (LTE) consisting of successive PEDOT:PSS and silver-nanowire (AgNW) layers. In particular, thermally induced phase separation (TIPS) of the PEDOT:PSS film is found to depend on the annealing temperature () during preparation of the LTE. At close to the glass transition temperature of the PSS chains, a PSS-rich phase with a large number of PSS molecules enhances the work function of the PEDOT:PSS on the glass-side surface relative to the air side. By using the optimized LTEs, bidirectional laminated PLEDs are obtained with a total external quantum efficiency of 2.9% and a turn-on voltage of 2.6 V, giving a comparable performance to that of the reference bottom-emitting PLED based on a costly evaporated metal electrode. In addition, an analysis of the angular characteristics, including the variation in the electroluminescence spectra and the change in luminance according to the emission angle, indicates that the laminated PLED with the LTE provides a more uniform angular distribution regardless of the direction of emission. Detailed optical and electrical analyses are also performed to evaluate the suitability of LTEs for the low-cost fabrication of efficient PLEDs.
在各种导电聚合物中，聚（3,4 - 亚乙基二氧噻吩）：聚（4 - 苯乙烯磺酸盐）（PEDOT:PSS）薄膜作为一种有前途的材料，被用于有机光电器件中的透明电极和空穴注入层。由于对低成本制造有机发光二极管（OLED）的需求不断增加，PEDOT:PSS已通过涂层或层压方法用作顶部电极。在此，报道了一种简便的方法，用于制造基于由连续的PEDOT:PSS和银纳米线（AgNW）层组成的层压透明电极（LTE）的高效聚合物发光二极管（PLED）。特别地，发现PEDOT:PSS薄膜的热致相分离（TIPS）取决于LTE制备过程中的退火温度（）。在接近PSS链的玻璃化转变温度时，富含大量PSS分子的PSS富集相相对于空气侧提高了玻璃侧表面上PEDOT:PSS的功函数。通过使用优化的LTE，获得了双向层压PLED，其总外量子效率为2.9%，开启电压为2.6 V，性能与基于昂贵的蒸发金属电极的参考底部发射PLED相当。此外，对角度特性的分析，包括电致发光光谱的变化和根据发射角度的亮度变化，表明具有LTE的层压PLED无论发射方向如何都提供更均匀的角度分布。还进行了详细的光学和电学分析，以评估LTE对于低成本制造高效PLED的适用性。
