热处理提高蓝色有机电致发光器件性能的研究

Enhancement of the Luminescence Performance of Polymer BlueLightEmitting Diodes with Single Layer Structure by Heattreatment

选取梯形次对苯基聚合物LPPP和小分子二唑材料OXD-7分别作为具有空穴转移特性的发光层材料及电子输运材料制备了蓝色有机电致发光(OEL)器件,采用热处理方法显著地提高了其发光性能,其最佳热处理条件为:真空中,170℃,1h。初步分析了热处理提高器件发光性能的原因,主要有两个因素:高温作用促进异质结的形成;热处理改善器件阴极/有机薄膜界面的接触状况,有效地减少器件工作中产生的黑斑。

Heat treatment at low vacuum on LPPP:OXD-7 polymer blue-light-emitting diodes with single-layer structure at different temperature was performed. Our experiments indicated that the optimum heat treatment condition for the above device is 170°C, 1 h. Then, the turn-on voltage of the device is reduced by 1 V, the maximum EL intensity is increased by 5.5 times and the relative energy efficiency is improved by 10. 0 times at 13 V. We consider that this mechanism can be attributed to the follow reasons: heat treatment promotes the formation of heterojunction between LPPP and OXD-7 and improves the characteristics of the interface between the light emitting polymer and the cathode, this can reduce black spots caused by the evolved gases which were probably produced by the electrolysis of water coming from the humid air and as a result, the electron injection is improved.