Tetracoordinate Boron‐Based Multifunctional Chiral Thermally Activated Delayed Fluorescence Emitters

Abstract

Purely organic emitters have shown great potential but still suffer from low efficiency in nearinfrared organic light-emitting diodes (NIR-OLEDs) due to the intensive non-radiative recombination. In this contribution, two pairs of thermally activated delayed fluorescence (TADF) enantiomers (R/S-DOBP and R/S-HDOBP) with tetracoordinate boron geometries were designed and synthesized. The TADF emitters simultaneously showed aggregation-induced emission, circularly polarized luminescence, high-contrast mechanochromism, and piezochromism behaviors. More importantly, R/S-DOBP and R/S-HDOBP revealed high photoluminescence quantum yields and efficient reverse intersystem crossing in neat films. The nondoped solutionprocessed OLEDs based on these unique emitters revealed the NIR emission (peaking at 716 nm) with a maximum external quantum efficiency of 1.9 % and high exciton utilization efficiency of 86 %, which represent one of the best solution-processed nondoped NIR-OLEDs.

NIR TADF emitters and OLEDs: challenges, progress, and perspectives

“…The R-DOBP based non-doped solutionprocessed OLEDs revealed the NIR emission (peaking at 716 nm) with a maximum external quantum efficiency of 1.9% and high exciton utilization efficiency of 86%, which represent one of the best solution-processed non-doped NIR-OLEDs. [69] In this review, besides Scheme 1-3 as we mentioned above, we also listed the host materials mentioned in the review in Scheme 4. Moreover, the photophysical properties of TADF emitters we have mentioned before could be found in Table 1, corresponding device structures and performances were further listed in Table 2.…”

“…The R-DOBP based non-doped solution-processed OLEDs revealed an NIR emission (peaking at 716 nm) with a maximum external quantum efficiency of 1.9% and high exciton utilization efficiency of 86%, and are some of the best solution-processed non-doped NIR-OLEDs. 69 …”

Thermally activated delayed fluorescence with dual-emission and pressure-induced bidirectional shifting: cooperative effects of intramolecular and intermolecular energy transfer

“…26 The introduction of fluorine atom is used to enhance intramolecular and intermolecular electron communications. [27][28][29] 9,9-dimethyl-9,10-dihydroacridine (DMAC) and 10H-phenoxazin (PXZ) are commonly employed as donor units in TADF systems due to their rigid structure, controllable electrondonating ability and easy implementation, [30][31][32][33][34] but they are used in UV TADF materials for the first time.…”

Highly Efficient Sky‐Blue π‐Stacked Thermally Activated Delayed Fluorescence Emitter with Multi‐Stimulus Response Properties

“…[9][10][11][12][13][14][15][16][17][18][19][20][21] Unfortunately, the stimulus-responsive luminescent behavior of most D-π-A molecules is relatively homogeneous, and these studies are relatively scattered. Moreover, many π-conjugated MSR molecules have weak molecular conformational stability or/and low exciton utilization rate, [2,7,11,27] especially under electrical stimulation, thus limiting their application in electroluminescence devices. Recently, the utilization of π-stacked molecules with high exciton utilization has aroused interest because of not only their unique molecular structure and luminescence properties but also their propensity to exhibit noncovalent intramolecular interactions, which could serve as a driving force in the MSR properties.…”

“…Organic materials with multi-stimulus response (MSR) properties possess significant value in chemistry, [1,2] biotechnology, [3,4] and materials science. [5][6][7][8] MSR materials are designed to respond to one or more environmental stimulation, such as chemical environment, [9,10] pressure, [11][12][13] light, [14] and electric field, [15] via several different mechanisms including changes in inter/intramolecular interactions, [6,[16][17][18][19] phase transitions, [16,20] and/or excited-state transformations.…”