在空穴传输层TCTA与电子传输层TPBi之间引入磷光染料Ir(ppy)3超薄发光层,制备了结构为ITO/MoO_3(2 nm)/NPB(40 nm)/TCTA(10 nm)/Ir(ppy)3(xnm)/TPBi(40 nm)/LiF(1 nm)/Al(80 nm)的非掺杂磷光有机电致发光器件。通过调控非掺杂发光层的厚度,详细研究了Ir(ppy)3层厚度对器件性能的影响。实验结果表明,当非掺杂发光层厚度为0.2 nm时,器件的性能最好,器件的亮度、效率和外量子效率分别达到26 350 cd·m(-2)、42.9 cd·A(-1)和12.9%。研究结果表明,采用超薄的非掺杂发光层可以简化器件结构和制备工艺,获得高效率的OLED器件。
The nondoped emitting layer( EML) was constructed by introducing a ultrathin layer of pure green phosphorescent dye tris( 2-phenylpyridine) iridium[Ir( ppy)3]between a hole transporting layer TCTA and an electron transporting layer TPBi. The device structure is ITO / MoO_3( 2 nm) /NPB( 40 nm) / TCTA( 10 nm) / Ir( ppy)3( 0. 1-0. 5 nm) /TPBi( 40 nm) /Li F( 1 nm) /Al( 80 nm).The thickness of EML can affect the performance of green phosphorescent organic light emitting diodes( Ph OLEDs). By changing the thickness of emitting layers,the best performance of green PhOLEDs can be achieved with a 0. 2 nm pure phosphorescent dye. The device exhibits highly efficient green emission with a maximum luminance of 26 350 cd·m(-2),a maximum current efficiency of 42. 9 cd·A(-1) and a maximum external quantum efficiency of 12. 9%. These results indicate that the high performance PhOLEDs can be realized with only ultrathin nondoped EMLs in a simple way.