制备了蓝光染料BCzVB和红光染料Btp2Ir(acac)共掺杂的白色有机电致发光器件。保持蓝光染料掺杂浓度为69/6而将红光染料掺杂浓度从6%,3%,1%减小到0.2%,器件色坐标从(0.60,0.35)调整至(0.55,0.34),(0.45,0.30)和(0.34,0.27),实现了白光发射。并且,器件在驱动电流4~200mA/cm^2变化范围内,发光色坐标稳定,几乎不随驱动电流密度的增大而漂移。对器件发光光谱和亮度-电流密度曲线等分析表明:器件色度的稳定性是由CBP基质向Btp2Ir(acac)掺杂剂完全的能量传递、蓝光染料BCzVB向红光染料Btp2Ir(acac)不完全的能量传递等内在物理过程决定的。
White organic electroluminescent devices (OLEDs) are constructed with a structure of ITO//NPB/CBP:BCzVB: Btp2Ir(acac)/BAlq/Alq/LiF/Al. Keeping the blue dye BCzVB dopant concentration of 6% and decreasing the red dye dopant concentration of from 6 %, 3%, 1% to 0.2%. The color coordinates change from (0.60, 0.35) to (0.55, 0.34), (0.45, 0. 30) and (0.34,0.27). And color coordinates of these devices remains unchanged with driven current density range from 4 mA/cm^2 to 200 mA/cm^2. The reason of the chromaticity stability has been discussed in detail. It is found that the color purity stability of devices are jointly determined by complete energy transfer from host CBP to dopant Btp2Ir(acac) and incomplete energy transfer from blue dye of BCzVB to red dye of Btp2Ir(acac).