Investigation of Förster-type energy transfer in organic light-emitting devices with 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethy ljulolidin-4-yl-vinyl)-4H-pyran doped cohost emitting layer

Abstract

Organic light-emitting devices ͑OLEDs͒ with cohosted emitter, which is composed of 9,10-di͑2-naphthyl͒anthracene ͑ADN͒ and tris͑8-hydroxy-quinolinato͒ aluminum ͑Alq 3 ͒ and doped with 4-͑dicyanomethylene͒-2-t-butyl-6-͑1,1,7,7-tetramethy ljulolidin-4-yl-vinyl͒-4H-pyran ͑DCJTB͒, were fabricated and studied. The efficiency of OLEDs with a cohost emitter was higher than that with a single host emitter. For the cohost emitter with ADN/ Alq 3 weight ratio of 75:25, the 3.4 cd/A efficiency of the resulted OLEDs was obtained. It is found that the absorption spectra of DCJTB and the emission spectra of Alq 3 changed with the composition of the emitter. This phenomenon is attributed to the polarization effect. On the basis of the Förster's theory, the resulted overlap integral exhibits the highest value for this cohost emitter. The experimental results reveal that the cascade energy transfer plays an important role in the luminance efficiency enhancement of the cohost emitter in OLEDs.

Effects of Green Emission on the Performance of White Organic Light-Emitting Devices and Their Electroluminescent Characteristics

“…This implies that the multiple doping essentially promotes energy transfer, which reduces the driving voltage. In addition, efficient energy transfer from the matrix to the guest plays a significant role in promoting emission intensity . From Figure and Table , we can see that WOLEDs with the component of green emission show higher emission intensity than WOLED without the component of green emission.…”

White organic light‐emitting diodes based on C545T doped emitting system

“…For these two cases, the former would be dominant because the increase in thickness is only 2 nm. In addition, efficient energy transfer from matrix to guest plays a significant role in promoting emission intensity 18. It is interesting to note that Cell‐S achieves a maximum luminance of 28 160 cd/m 2 at 13 V. This could be in relation to the high energy transfer ability of Cell‐S as compared to Cell‐D.…”

Quantifying Interdopant Exciton Processes in Organic Light Emitting Diodes

“…Several studies have investigated energy transfer processes in OLEDs by observing changes in the intensity of electroluminescent (EL) spectra. − These studies only present qualitative information on how a factor affects energy transfer efficiency and are often limited to studying only either Dexter or Förster transfer. Additionally, relative energy transfer efficiency is often deduced based on spectral overlap and triplet/singlet energy levels of the donor and acceptor materials. , A large overlap between the emission spectrum of the donor and the absorption spectrum of the acceptor is needed to facilitate energy transfer.…”