磁控溅射法制备TiO2空穴缓冲层的有机发光器件

采用磁控溅射方法在ITO表面制备了不同厚度的TiO2超薄膜用做有机发光二极管（OLEDs）的空穴缓冲层，使OLEDs（ITO／TiO2／TPD／Alq3／Al）的发光性能得到很大改善。研究TiO2缓冲层厚度对器件性能影响的结果表明，当TiO2缓冲层厚度为1nm，电流密度为100mA／cm^2时，器件的发光效率为2cd／A，比未加缓冲层器件的发光效率增加了近一倍。这是由于加入适当厚度的TiO2缓冲层限制了空穴的注入并且提高了空穴与电子注入之间的平衡。

Investigation on organic light-emitting diodes with TiO2 ultra-thin films as hole buffer layer by RF magnetron sputtering

Organic light-emitting diodes(OLEDs) using TiO_2 ultra-thin films as a hole injecting buffer layer of different thicknesses were prepared by RF magnetron sputtering.The diodes with a typical structure of ITO/ TiO_2/ TPD/ Alq_3 / Al(TPD : N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine,Alq_3 : tris(8-quinolinolato)-aluminum) show better electroluminescent properties in comparison with the samples without TiO_2 buffer layer.The investigation on the effects of the thickness for TiO_2 shows that EL efficiency of the device,which contains 1 nm TiO_2 buffer layer,is improved to 2 cd/A by approximately 100% in comparison with the device without buffer layer at the current density of 100mA/cm~2.It can be attributed to the limit of the injecting number of hole and the improvement of the balance of hole and electron injections by the TiO_2 ultra-thin film with suitable thickness as a hole buffer layer.