基于PVK的高色纯度高稳定性有机电致红光器件

利用旋涂法和真空蒸镀法相结合的方法,根据能量空间传递的原理制备了PVK ∶ Ir(piq)₂(acac)体系的红色有机电致发光显示器件。器件的结构为ITO/CuPc/PVK ∶ Ir(piq)₂(acac)/BCP/Alq₃/LiF/Al。研究了不同主客体掺杂比对器件发光性能的影响,得到了高色纯度、单色性较好的红光器件。当Ir(piq)₂(acac)掺杂的质量比为1 ∶ 0.08时,器件的综合性能达到最佳,发光峰位于625 nm,CIE坐标为(x=0.66,y=0.33)。通过对各层厚度的合理选择,形成相对优化的微腔结构,充分利用其对光谱的窄化效应,使得器件的EL光谱的发射半峰全宽仅为55 nm,提高了器件的发光性能。器件光谱具有很好的单色性,色纯度达到98.2%。

Organic Red Electroluminescence Devices Based on PVK with High Color Purity and High Stability

Since Tang and VanSlyke developed an efficient organic light-emitting diode (OLED) based on an organic bilayer structure in 1987, the efficiency has been increased, particularly, the use of n- and p-doped organic transport materials with small-molecule OLEDs leads to improving conductivities and significantly better injection of charge carriers into the OLED. Further concepts have been established such as the insertion of additional organic layers as exciton and charge carrier blockers which can localize the emission zone and prevent exciton quenching effects as well as charge carrier imbalance. In spite of rapid advances in the organic electroluminescent device (OELD), there have still been many hurdles to be overcome for manufacturing a high-resolution full color display. The development of a stable, efficient, and saturated red device remains an important goal for OLEDs which is obtained by using a discrete emitting layer or doping fluorescent and phosphorescent dyes into a host layer. In this report,a organic red electroluminescent device was fabricated based on hole transporting material PVK doped with Ir(piq)_2(acac) by the spin-coating method and vacuum evaporate plating technology. The structure of the device is ITO/CuPc/PVK:Ir(piq)_2(acac)/BCP/Alq_3/LiF/Al. The effect of the doping ratio on the performance of the device was investigated. The device has high perfor-mance when the doping ratio is 1:0.08 in mass that the CIE coordinate is located at (x=0.66,y=0.33) and the main emission peak is at 625 nm. The full width at half maximum of the spectrum is only 55 nm. It is attributed to the structure of micro-cavity which is improved by the reasonable thickness of films. The color of a dye can be modified by inserting it into a microcavity. Indeed, a microcavity is formed within a OLED by weak reflections from interfaces. The spectrum of the device has fine monochromaticity that the color purity is 98.2%. The luminescence performance of the device is well improved.