The Performance of OLEDs Improved by Co-doping PEDOT: PSS Films
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摘要: 为了克服PEDOT: PSS作为空穴注入层时强酸性和低导电性的问题，采用将适量咪唑和碘化铯共掺杂于PEDOT: PSS的方法，制备了高效有机电致发光器件(OLEDs)。结果表明：有效调节PEDOT: PSS的酸碱性，可提高PEDOT: PSS的空穴注入能力，使载流子传输更加平衡。与纯PEDOT: PSS作空穴注入层的OLEDs相比，优化后器件的最大亮度和电流效率分别提高了30%和31%。该研究为掺杂PEDOT: PSS为空穴注入层在OLEDs领域的研究提供了理论和实验参考。Abstract: In order to overcome the problems of strong acidity, low conductivity of PEDOT: PSS which as hole injection layer in OLEDs, an appropriate amount of imidazole and cesium iodide was co-doping into PEDOT: PSS to prepare efficient OLEDs. The results show that co-doping can effectively adjust the acidity and alkalinity of PEDOT: PSS, improve the hole injection capacity of PEDOT: PSS, so that the carrier transport is more balanced. Compared with OLEDs with pure PEDOT: PSS as hole injection layer, the maximum luminance and current efficiency of the optimized device are increased by 30% and 31%, respectively. This study provides theoretical and experimental reference for the research of doping PEDOT: PSS as hole injection layer in the field of OLEDs.
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Key words:
- organic light-emitting devices /
- hole injection layer /
- co-doping /
- current efficiency /
- luminance
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图 2 不同PEDOT: PSS样品的SEM图及0.5%掺杂样品的EDS图
Figure 2. The SEM images of different PEDOT: PSS samples and the EDS images of the 0.5%-doped sample
图 3 器件示意图、XRD图谱以及不同薄膜的元素分布EDS图
Figure 3. The device schematic diagram, XRD diagram and EDS diagram of element distribution of different films
图 4 OLEDs器件的EL光谱、电流效率-亮度曲线以及亮度-电压曲线
注：A图插图为器件在9.0 V下的发光照片；C图插图为器件的色坐标。
Figure 4. The FL spectra, curves of current efficiency-luminance and of luminance-voltage
图 5 咪唑吸收光谱与不同PEDOT: PSS薄膜的透射光谱
Figure 5. The absorption of imidazole and the transmittance of different PEDOT: PSS films
图 6 以不同PEDOT: PSS薄膜为HIL的单空穴器件电流密度曲线
Figure 6. The current density curves of hole-only devices with different PEDOT: PSS films as HIL
图 8 不同PEDOT: PSS薄膜的XPS谱与归一化亮度-时间曲线
Figure 8. The XPS spectra of different PEDOT: PSS films and the normalized luminance as a function of time
表 1 不同CsI掺杂率下OLEDs的性能参数
Table 1. The performance of OLEDs with different doping concentrations of CsI
掺杂率/% 启亮电压/V 最大亮度/(cd·m-2) 最大电流效率/(cd·A-1) CIE(x, y) 0 4.0 19 310 4.27 (0.31, 0.50) 0.1 4.2 22 470 5.11 (0.30, 0.48) 0.3 4.5 25 110 5.61 (0.31, 0.48) 0.5 4.9 21 420 4.89 (0.31, 0.48) 
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