硅片上顶发射的有机电致发光器件

Top-emitting Organic Light-emitting Devices Based on Silicon Substrate

为了更好地实现有机发光器件在硅片上的有源矩阵显示,有必要探讨在硅片上直接制作透明阴极的顶发射有机发光器件。在顶发射发光器件中,为了到达高的发光效率,底部阳极一般采用高反射率的金属。在通常所用的各种金属当中,金属银对可见光具有很高的反射率,然而由于其具有相当低的功函数,导致与有机材料间能级的不匹配,从而引起有机发光器件中阳极空穴注入的不理想而影响器件的性能。我们在硅片上制备顶发射的有机发光器件,用薄层QAD(quinacridone)作为发光层,表面修饰的银作为阳极,制备的有机发光器件的亮度在外加电压10V时达到13 700cd/m2,器件的最大电流效率在7V时达到4. 3cd/A,是没有薄层QAD器件的2倍多,是由在器件中存在Alq3 与QAD之间F ster能量转移机制引起的。

Top-emitting organic light-emitting devices (OLEDs) offer a feasible fabrication of OLED displays on opaque substrates, such as Si wafers and active-matrix backplanes with complicated pixel circuits of thin-film transistors and integrate circuit. In top-emitting OLEDs, high reflectivity of the bottom anode is essential for achieving high luminance efficiency. Among various metals, Ag has the highest reflectivity for visible light. However, it is generally not considered as an ideal hole-injecting anode for OLEDs due to its rather low work function, not matching well the ionization potentials of organic materials commonly used in OLEDs. In this letter, we report a top-emitting organic light-emitting device on silicon substrate with high luminance and current efficiency utilizing Ag as electrodes and ultrathin quinacridone(QAD) as emitting layer. Surface-modified Ag and thin Ag films act as anode. The luminance reaches 13 700 cd/m 2 at 10 V and the maximum current efficiency of the device using such electrode is 4.3 cd/A at 7 V, which is about twice times than those devices without QAD. The improved performance is owing to the characteristics of quinacridone, which accepts excitation energy from tris(8-hydroxyquinoline) aluminium via Fster mechanism.