不同掺杂顺序的磷光OLED器件发光性能的研究

绿色GIr1和红色R-4B磷光染料，采用红绿红、绿红、红绿、绿红绿等顺序，与主体材料CBP共蒸，制备了四种红绿磷光器件，并结合TCTA和BCP对载流子和激子的阻挡作用，研究了发光层掺杂顺序对器件性能的影响。结果表明，四种器件光谱、光效、亮度和发光颜色均有较大差异，且BCP和CBP界面附近是主要的激子复合区。在电压为5v,红绿红掺杂型器件，亮度、电流效率和色坐标分别为40.12 cd·m-2，7.68 cd·A-1 和(0.630 1，0.365 4);而绿红绿掺杂型器件为104 cd·m-2，19.75cd·A-1和(0.371 7，0.576 8)。分析认为：CBP与GIr1，R-4B，BCP，TCTA有较大的LUMO能级差异，发光层中电子的主要传输方式为掺杂分子上的俘获和分子间跳跃，不同掺杂顺序会形成不同能级势垒分布，发光层内电荷累积形成的空间电场分布不同。

Properties of Phosphorescent Organic Light-Emitting Diodes with Different Doping Order on Light Emitting Layer

Utilizing GIr1(green) and R-4B(red) phosphorescent dye, organic light-emitting diodes with different doping orders on red and green light-emitting layers were fabricated. The authors investigated the luminescent properties of devices combined with the effect of electron (TCTA) and hole (BCP) blocking layer. The results showed that the great impacts on spectrum, light efficiency, luminance and luminescent color were produced based on different doping order, and the authros also found the strong emission peak at the interface of the BCP and CBP layer. With the use of the red and green doping type, 0.527 mA·cm-2, 104 cd·m-2, 19.75 cd·A-1 and (0.371 7，0.576 8) could be reached, respectively. The reasons were that on the one hand, because of large difference between energy levels of host material CBP and doping material GIr1, R-4B, and charge trapping and hopping via dopants were the main mechanism of change; on the other hand, for the different energy levels between dopants and blocking layers, the doping sequence could affect barrier distribution, and then affect the electric field distribution.