Hybrid white organic light-emitting devices consisting of a non-doped thermally activated delayed fluorescent emitter and an ultrathin phosphorescent emitter

Abstract

Hybrid white organic light-emitting devices (OLEDs) are fabricated by employing non-doped emitting layers (EMLs), which are consisted of a blue thermally activated delayed fluorescent (TADF) emitter 9, 9-dimethyl-9, 10-dihydroacridine-diphenylsulfone (DMAC-DPS) and an ultrathin yellow iridium complex bis[2-(4-tertbutylphenyl)benzothiazolato-N,C 2 '] iridium (acetylacetonate) [(tbt) 2 Ir(acac)]. With thickness optimization of DMAC-DPS, a white OLED achieves maximum current efficiency, power efficiency, and external quantum efficiency of 34.9 cd/A, 29.2 lm/W, and 11.4 %, respectively, as well as warm white emission with relatively stable electroluminescence spectra. The results suggest that, bipolar charge carrier transport property and concentration independent property of DMAC-DPS, charge carrier trapping effect of the ultrathin (tbt) 2 Ir(acac), and balanced self-emission process and energy transfer process between DMAC-DPS and (tbt) 2 Ir(acac), contribute to high device performance.

Investigation of Energy Transfer in Star-Shaped White Polymer Light-Emitting Devices via the Time-Resolved Photoluminescence

“…However, the PL spectra in films showed in Figure 6 c exhibits the main blue emission peaks as well as the weak green emission originating from FO moieties, which is because simultaneous intramolecular and intermolecular FRET processes generate more excited FO units and result in stronger green emission peaks. The energy transfer efficiency (E t ) could be calculated from Equation (2) [ 35 , 36 ], where is the lifetime of star-like PFO and is the lifetime of copolymer films. The E t is also listed in Table 2 .…”

Recent progress on organic light-emitting diodes with phosphorescent ultrathin (<1nm) light-emitting layers

“…In this respect, a sky-blue TADF emitter DMAC-DPS first caught the eye of researchers because of its high T 1 level (2.9 eV) and PLQY (0.88) in neat film. In addition, DMAC-DPS also exhibits a broad emission spectrum with a full width at half maximum of about 80 nm ( Wang et al., 2017 ; Zhao et al., 2017 ). Thus, in 2017, Yu et al.…”

“…The reasons are follows as: Firstly, blue TADF emitters possess high T 1 and high efficiency compared with the conventional blue fluorescent emitters because of their sufficiently small energy gap between the singlet and triplet states and the potential of realizing exciton utilization of 100%; Second, blue TADF emitters usually exhibit the good bipolar transport characteristics because of the natural existence of donor and acceptor segments that could transport the holes and electrons, respectively, which can contribute to a broadened carrier recombination zone; Third, recent research works proved that many blue In this respect, a sky-blue TADF emitter DMAC-DPS first caught the eye of researchers because of its high T 1 level (2.9 eV) and PLQY (0.88) in neat film. In addition, DMAC-DPS also exhibits a broad emission spectrum with a full width at half maximum of about 80 nm Zhao et al, 2017). Thus, in 2017, Yu et al firstly inserted an orange phosphorescent UEML in a blue TADF EML structured by heavily doping DMAC-DPS in DPEPO host, to fabricate complementary hybrid white OLEDs (Qi et al, 2017a), and the optimized device structure is ITO/ MoO 3 (10 nm)/ TAPC(40 nm)/ mCP(10 nm)/ DPEPO: 50wt% DMAC-DPS(9 nm)/ (tbt) 2 Ir(acac)(0.1 nm)/ DPEPO: 50wt% DMAC-DPS(6 nm)/ Bphen(40 nm)/ Mg: Ag (100 nm).…”

Investigation of Theoretical and Experimentical Properties of 2-[3-(n-Propyl)-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl]-Phenoxyacetic Acide

“…The development of new heterocyclic organic compounds has received considerable attention due to their potential fluorescence applications as chemosensors (Qin et al, 2015), ionic or biological probes (Mecca et al, 2016;Beytur, 2020) and lighting Technologies (Kido et al, 1995;Sun et al, 2006;Yang et al, 2015;Zhao et al, 2017). The biological activities of the Schiff bases in medicinal chemistry are attributed to the presence of groups in literature (Sztanke et al, 2013;Alkan et al, 2007;Gürsoy-Kol et al, 2010;Aktaş-Yokuş et al, 2017;Bahçeci et al, 2016;Bahçeci et al, 2017;Boy et al, 2021;Koç et al, 2019).…”