Highly efficient phosphor-converted white organic light-emitting diodes with moderate microcavity and light-recycling filters

Abstract

We demonstrate the combined effects of a microcavity structure and light-recycling filters (LRFs) on the forward electrical efficiency of phosphor-converted white organic light-emitting diodes (pc-WOLEDs). The introduction of a single pair of low- and high-index layers (SiO(2)/TiO(2)) improves the blue emission from blue OLED and the insertion of blue-passing and yellow-reflecting LRFs enhances the forward yellow emission from the YAG:Ce(3+) phosphors layers. The enhancement of the luminous efficacy of the forward white emission is 1.92 times that of a conventional pc-WOLED with color coordinates of (0.34, 0.34) and a correlated color temperature of about 4800 K.

Efficient fluorescent OLEDS based on assistant acceptor modulated HLCT emissive state for enhancing singlet exciton utilization

“…86,87 The DDPPPA and DDPBA based OLEDs show improved device efficiencies of h ex of 4.72% (5 wt% DDPPPA) and 5.63% (5 wt% DDPBA). 88 The doped device m-MTDA-TA:DDPPPA/m-MTDATA:DDPBA show maximum efficiencies of h c À7.4/8.23 cd A À1 ; h p À5.8/6.13 lm W À1 ; h ex À4.72/5.63% The theoretically calculated maximum h EQE is of 5.61/5.20% DDPPPA (neat/20 wt% m-MDATA) and 5.55/5.10% DDPBA (neat/ 20 wt% m-MDATA) [h EQE ¼ h out  h rec  h g  F PL , 89 f PL :-DDPPPA (89/96%) and DDPBA (90/98%), h outout-coupling efficiency (20%), h recproduct of charge recombination efficiency (100%), h gradiative exciton-production (25%)] and the experimental h EQE is of 5.70/5.96% DDPPPA (neat/20 wt%) and 6.01/6.25%, DDPBA (neat/20 wt%) respectively. Similar trend is observed by using TAPC as host (experimental h EQE :DDPPPA/ DDPBA:TAPC -5.96/6.25 > theoretical h EQE DDPPPA/ DDPBA:TAPC -5.61/5.56).…”

Color-tunable white organic light-emitting diodes with a red dopant as the color conversion layer

“…Although the multilayer light-emitting layer WOLED device has higher efficiency than single light-emitting layer WOLED device, CIE(x, y) chromaticity coordinates typically rely on the device driving voltage. Due to the increase of driving voltage will lead to electron-hole recombination zone offset, the device color stability is generally lower [6][7][8].…”

High color rendering index and chromatic stability of top‐emitting white organic light‐emitting diodes capped with a supplementary green color conversion layer

“…In addition, it is important to keep chromaticity stable for WOLEDs with the variation of bias. The method of color conversion is an appropriate method for obtaining WOLEDs with stable chromaticity 11–15. It is necessary and urgent to obtain high‐CRI and stable‐chromaticity TEWOLEDs, especially for the lighting application.…”