Doping-free orange and white phosphorescent organic light-emitting diodes with ultra-simply structure and excellent color stability

Doping-free tandem white organic light-emitting diodes

“…Since doping-free tandem WOLEDs can avert the use of host and doping charge injection layers, shorten the fabrication time and reduce the cost, they may have great potential to the future commercialization. The maximum power efficiency (PE) is 42.9 lm/W, slightly decreasing to 42.0 and 32.6 lm/W at 100 and 1,000 cd/m 2 , respectively, among the highest doping-free WOLEDs [24][25][26][27][28]. Besides, it is noted that the efficiency roll-off of W1 is among the lowest doping-free WOLEDs.…”

“…Adachi and co-workers [22] constructed doping-free green and blue OLEDs by using thermally activated delayed fluorescence (TADF) emitters, achieving nearly 100% internal quantum efficiency. Besides, some doping-free single-unit WOLEDs have been reported and the record efficiency is 41.3 cd A À1 [24][25][26][27][28]. Based on these facts, it can be concluded that the doping-free technique is an effective scheme to develop OLEDs.…”

Large-area, uniform white light LED source on a flexible substrate

“…The luminous efficiency of cool white LED (5000K of CCT) is 120 lm/W and CRI is 70 whereas the warm white LED (3000K of CCT) can obtain 80 lm/W and CRI value of 81. Moreover, compared to other studies related to large-area lighting source [19][20][21], the luminous efficiency of the proposed device is compatible and has the potential to use in the flexible lighting application because of high lumen efficiency and low cost. Furthermore, we measure the luminance of the flexible white LED at nine point measurement method and calculate the uniformity with the formula:…”

Recent Advances of Exciplex-Based White Organic Light-Emitting Diodes

“…Nowadays, many approaches have been reported to develop high-performance WOLEDs, including managing singlet and triplet excitons for hybrid structures [72][73][74][75], harvesting triplets from blue fluorophors with high T 1 [76][77][78][79][80], having charge-and exciton-confining structures to reduce the efficiency roll-off [81][82][83], combining blue/green/red phosphors with light-outcoupling enhancement techniques [84], adopting color down-conversion media [85], comprising ultrathin emitting layers (EMLs) [86][87][88][89][90], using tandem architectures [91][92][93][94][95], employing excimer systems [96][97][98], eliminating interlayer in hybrid WOLEDs [99,100], and exploiting double multifunctional blue EMLs [101]. Among them, the use of exciplexes in WOLEDs has been actively investigated, since exciplexes can be effectively functioned as (i) fluorescent or TADF emitters; (ii) the hosts of fluorescent, phosphorescent and TADF dopants [102][103][104][105][106][107][108][109][110].…”