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通过将荧光共轭聚合物G-PF(芴与噻吩的共聚物)与聚苯乙烯(PS)共混制备出了高效率的聚合物发光二极管.当采用G-PF与PS的浓度比为80/20的共混物薄膜为发光层时,其器件最高量子效率为12 cd/A,而纯的荧光共轭聚合物G-PF器件的最高量子效率只有6.5 cd/A.通过对其电致发光谱和光致发光谱的研究,发现量子效率的提高主要是因为聚苯乙烯的加入,增加了荧光共轭聚合物链间的距离,减少了容易发生无辐射跃迁的链间复合物的形成,从而提高了荧光共轭聚合物的荧光量子产率.聚苯乙烯的浓度超过20％后,再进一步增加聚苯乙烯的含量,会导致器件的量子效率下降.这可能是由于聚苯乙烯本身是一种绝缘材料,它的加入会降低电子与空穴的传输性能,从而减少了正负载流子复合的概率.
A highly efficient polymer light-emitting diode was prepared by blending a fluorescent conjugated polymer G-PF (copolymer of fluorene and thiophene) with polystyrene (PS) .When a concentration ratio of G-PF to PS of 80 / 20 is a luminescent layer, the highest quantum efficiency of the device is 12 cd / A, while the highest quantum efficiency of a pure fluorescent conjugated polymer G-PF device is only 6.5 cd / A. The results show that the increase of quantum efficiency is mainly attributed to the addition of polystyrene, the increase of the distance between the fluorescent conjugated polymer chains and the reduction of the formation of interchain complexes which are prone to nonradiative transition. Thereby increasing the fluorescence quantum yield of the fluorescent conjugated polymer.When the concentration of polystyrene exceeds 20%, further increase of the content of polystyrene will result in a decrease of the quantum efficiency of the device.This may be due to the fact that polystyrene itself is An insulating material whose addition reduces the transport of electrons and holes, reducing the probability of positive and negative carrier recombination.