Multifunctional Triphenylamine/Oxadiazole Hybrid as Host and Exciton‐Blocking Material: High Efficiency Green Phosphorescent OLEDs Using Easily Available and Common Materials

An efficient dual-emissive-layer white organic light emitting-diode: Insight into device working mechanism and origin of color-shift

“…Despite this issue, we can still estimate v FIrpicÀenergy transfer . We have demonstrated that the EQE of the optimized (fbi) 2 Ir(acac) device is $20% [24]. Here, the peak g FIrpic and EQE of WOLED-O are 13.3% and 17.9%, respectively.…”

Strategies to Design Bipolar Small Molecules for OLEDs: Donor‐Acceptor Structure and Non‐Donor‐Acceptor Structure

“…[ 26 ] This issue can be relieved by interrupting the π -conjugation between the electron-donating and electronwithdrawing moieties by incorporating steric groups and/or changing the linkage between the two moieties. Tao et al synthesized several TPA/OXD hybrids, [27][28][29] and the triplet energies of 19 and 20 were determined to be 2.35 eV and 2.46 eV, respectively, according to the highest-energy vibronic sub-band of the phosphorescence spectra at 77 K. Density functional theory (DFT) calculation results indicated that 20 has a nearly complete separation between the HOMO and LUMO located at the TPA and OXD sites, respectively, owing to the ortho -linkage of TPA and OXD; whereas 19 exhibits only a partial separation between the HOMO and LUMO because of its para -linkage. However, the PLQY of 20 is lower than that of 19 because of the reduced HOMO and LUMO overlap, which increases the rate of the competing intersystem crossing process.…”

“…A maximum EQE of 23.7% and a power effi ciency of 105 lm W − 1 were achieved in a green phosphorescent OLED with 21 as the host and the hole-blocking layer. [ 29 ] Bipolar hosts with carbazole as the HT moiety usually possess a higher triplet energy than their counterparts with TPA, as the triplet energy of carbazole (T 1 = 3.19 eV) is higher than that of TPA (T 1 = 3.04 eV). Tao et al synthesized several carbazole/ OXD hybrids as hosts for phosphorescent OLEDs.…”

Organometallic Versus Organic Molecules for Energy Conversion in Organic Light-Emitting Diodes and Solar Cells

“…Ir(ppy) 3 has been the most widely used green phosphor [10][11][12][13][14], for which the best device performance with a high η P of 133 lm/W was reported by Kido and his coworkers [12]. The green OLEDs based on its heteroleptic counterpart Ir (ppy) 2 (acac) were also reported to show attractive performance with η ext of 23.7 % and η P of 105 lm/W [15]. By using Ir(tfmppy) 2 (tfmtpip) as the green phosphor, a maximum η P and η L of 113.23 lm/W and 115.39 cd/A, respectively, were achieved at a doping level of 5 wt% [16], in which the introduction of CF 3 moiety to the Ir(III) complex was believed to increase the electron mobility of the complex and thus enhance the overall efficiencies of the device.…”