In four-color phosphorescent white organic light-emitting diodes (WOLEDs), the thickness ratio of the planar heterojunction spacer (NPB/mCP or NPB/TPBi) between green ultrathin emitting layer (UEML) and yellow UEML can change the capability and direction of exciton energy transfer in this heterojunction. When the thickness (y) of TPBi is 1.5 nm, the value of CRI increases to 93 in device B22 with NPB/TPBi spacer because that the position of recombination zone (RZ) and direction of exciton energy transfer in device B22 are different from that in device A without the planar heterojunction spacer. With little decline in CRI from 93 to 91, the luminance can be improved by reducing the doping concentration (z %) of FIrpic in the blue EML (close to electron transport layer) in device C2 based on the structure of device B22. As z is 3.3, the maximum luminance is 36230 cd/m², the shift of CIE_x,y is (0.0440, 0.0029) from 5.5V-8.5V in device C2.

在四色磷光白色有机发光二极管（WOLED）中，绿色超薄发光层（UEML）和黄色UEML之间的平面异质结间隔层（NPB / mCP或NPB / TPBi）的厚度比可以改变其能力和方向。激子在该异质结中的能量转移。当TPBi的厚度（y）为1.5 nm时，在带有NPB / TPBi间隔物的器件B22中，CRI的值增加到93，这是因为器件B22中的复合区（RZ）的位置和激子能量转移的方向与CBI的位置不同在器件A中没有平面异质结隔离层。在CRI从93下降到91的情况下，通过减小基于器件B22的器件C2中蓝色EML（靠近电子传输层）中FIrpic的掺杂浓度（z％），可以提高亮度。由于z为3.3，^{如图2所示}，在器件C2中，CIE _x，y从5.5V至8.5V的偏移为（0.0440，0.0029）。