The realization of luminescent materials with narrowband and circularly polarized luminescence (CPL) is of great significance for the development of future optical and photonic devices. Herein, ...through a steric‐hindrance‐assisted dual‐core strategy, two pairs of chiral dual‐core multiple resonance thermally activated delayed fluorescence (MR‐TADF) materials (R/S‐DOBN and R/S‐DOBNT) are directly constructed by the bonding of two organoboron MR‐TADF monocores (SOBN and SOBNT) with carbazole/3,6‐di‐tert‐butyl‐9H‐carbazole and phenol derivative as donors, realizing obvious CPL and narrowband emissions. Furthermore, the dual‐core effect in the prepared R/S‐DOBN and R/S‐DOBNT increases the transition oscillator strength two times more than that of a monocore structure, while maintaining the ultrapure blue emissions peaking at 453 and 459 nm with a narrower full‐width at half‐maximum of 21 nm through reorganization energy reduction. The circularly polarized organic light‐emitting diodes based on the enantiomers exhibit ultrapure blue emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.14, 0.10) and (0.13, 0.12), high maximum external quantum efficiencies of 23.9% and 25.6%, and obvious circularly polarized electroluminescence with dissymmetry factors (|gEL|) ≈ 10−3.
Through a steric‐hindrance‐assisted dual‐core strategy, chiral organoboron structures are prepared by direct bonding of two multiple‐resonance thermally activated delayed fluorescence (MR‐TADF) monocores, realizing superior chiroptical property and dual‐channel enhanced ultrapure blue emission. Furthermore, highly efficient circularly polarized organic light‐emitting diodes (CP‐OLEDs) with maximum external quantum efficiencies of 23.9% and 25.6% are achieved.
Chiral boron/nitrogen doped multiple resonance thermally activated delayed fluorescence (MR‐TADF) emitters are promising for highly efficient and color‐pure circularly polarized organic ...light‐emitting diodes (CP‐OLEDs). Herein, we report two pairs of MR‐TADF materials (Czp‐tBuCzB, Czp‐POAB) based on planar chiral paracyclophane with photoluminescence quantum yields of up to 98 %. The enantiomers showed symmetric circularly polarized photoluminescence spectra with dissymmetry factors |gPL| of up to 1.6×10−3 in doped films. Meanwhile, the sky‐blue CP‐OLEDs with (R/S)‐Czp‐tBuCzB showed an external quantum efficiency of 32.1 % with the narrowest full‐width at half‐maximum of 24 nm among the reported CP‐OLEDs, while the devices with (R/S)‐Czp‐POAB displayed the first nearly pure green CP electroluminescence with |gEL| factors at the 10−3 level. These results demonstrate the incorporation of planar chirality into MR‐TADF emitter is a reliable strategy for constructing of efficient CP‐OLEDs.
Two efficient planar chiral multiple resonance thermally activated delayed fluorescent compounds showing narrow emissions and circularly polarized luminescence were prepared. The sky‐blue circularly polarized organic light‐emitting diode exhibited the narrowest emission and high external quantum efficiency of 32.1 %, and the first nearly pure green circularly polarized electroluminescence was realized. Both devices display g factors at 10−3 level.
Click chemistry focuses on the development of highly selective reactions using simple precursors for the exquisite synthesis of molecules. Undisputedly, the CuI‐catalyzed azide–alkyne cycloaddition ...(CuAAC) is one of the most valuable examples of click chemistry, but it suffers from some limitations as it requires additional reducing agents and ligands as well as cytotoxic copper. Here, we demonstrate a novel strategy for the azide–alkyne cycloaddition reaction that involves a photoredox electron‐transfer radical mechanism instead of the traditional metal‐catalyzed coordination process. This newly developed photocatalyzed azide–alkyne cycloaddition reaction can be performed under mild conditions at room temperature in the presence of air and visible light and shows good functional group tolerance, excellent atom economy, high yields of up to 99 %, and absolute regioselectivity, affording a variety of 1,4‐disubstituted 1,2,3‐triazole derivatives, including bioactive molecules and pharmaceuticals. The use of a recyclable photocatalyst, solar energy, and water as solvent makes this photocatalytic system sustainable and environmentally friendly. Moreover, the azide–alkyne cycloaddition reaction could be photocatalyzed in the presence of a metal‐free catalyst with excellent regioselectivity, which represents an important development for click chemistry and should find versatile applications in organic synthesis, chemical biology, and materials science.
One more click! A novel design strategy for the azide–alkyne cycloaddition reaction by visible‐light catalysis through a photoredox electron‐transfer process (see scheme) has been developed for the first time. The reaction can be performed with a metal‐free catalyst in water using solar energy, making this a sustainable and environmentally friendly photocatalytic system, and represents an important development for click chemistry.
Herein, we report the structures of chiral‐at‐cage carborane derivatives bearing carbazole chromophores that emit circularly polarized luminescence (CPL) and aggregation‐induced ...electrochemiluminescence (AIECL). By adjusting the substituent positions on the carborane derivatives, two chiral luminescent molecules, Cb1 and Cb2, with different properties were obtained. The photoluminescence dissymmetry factors |gPL| of both (R/S)‐Cb1 and (R/S)‐Cb2 enantiomers in neat films were as high as 6.24×10−3 and 7.38×10−3, respectively. Cb1 showed a deep blue emission peak at 434 nm in n‐pentane. Interestingly, distinct fluorescence and CPL spectra were observed in solvents of different polarities due to the twisted intramolecular charge transfer effect, suggesting its potential use in solvent recognition. Meanwhile, Cb2 exhibited good AIECL property, excellent ECL stability and could be used for determining dopamine concentrations, suggesting its potential applications in biology and diagnosis.
Two chiral‐at‐cage carbazole‐modified carboranes emit circularly polarized luminescence (CPL) and aggregation‐induced electrochemiluminescence (AIECL). The |gPL| factors of (R/S)‐Cb1 and (R/S)‐Cb2 enantiomers in films reached 7.38×10−3. Significant solvation effect was observed in the fluorescence and CPL of Cb1, while Cb2 showed remarkable AIECL effect with excellent ECL stability and dopamine detection ability.
The circularly polarized organic light‐emitting diodes (CP‐OLEDs) demonstrate promising application in 3D display due to the direct generation of circularly polarized electroluminescence (CPEL). But ...the chiral luminescence materials face challenges as intricated synthetic route, enantiomeric separation, etc. Herein, fresh CP‐OLEDs are designed based on chiral hole transport material instead of chiral emitters. A pair of hole transport enantiomers (R/S‐NPACZ) exhibit intense dissymmetry factors (|gPL|) about 5.0 × 10−3. With R/S‐NPACZ as hole transport layers, CP‐OLEDs are fabricated employing six achiral phosphorescence and thermally activated delayed fluorescence (TADF) materials with different wavelengths, in consistence with the generated CPEL spectra. The CP‐OLEDs based on achiral red, green, and blue iridium(III) complexes exhibit external quantum efficiencies (EQEs) of 14.9%, 30.7%, and 14.1% with |gEL| factors of 8.8 × 10−4, 2.3 × 10−3, and 2.0 × 10−3, respectively. Moreover, the devices using achiral blue, blueish‐green, and green TADF materials display EQEs of 24.1%, 17.9%, and 25.4% with |gEL| factors of 1.0 × 10−3, 3.6 × 10−3, and 2.2 × 10−3, respectively. As far as known, it is the first example of CP‐OLEDs based on chiral hole transport materials, which act as the organic circularly polarizers and have potential to generate CPEL from achiral luminescence materials.
A pair of hole transport enantiomers are applied in fabrication of circularly polarized organic light‐emitting diodes first time with achiral luminescent materials as emitters, where the chiral hole transport enantiomers act as the organic circularly polarizers in principle. All devices exhibit symmetric circularly polarized electroluminescent spectra with dissymmetry factors ranging from 8.8 × 10−4 to 3.6 × 10−3.
This work describes the first hot exciton fluorescent material based on benzoc1,2,5thiadiazole and chiral binaphthol enabling circularly polarized luminescence (CPL) through a chiral perturbation ...strategy. The new molecular architecture displays CPL, hybridized local and charge transfer (HLCT) properties concurrently. Utilizing it as the emitter, circularly polarized organic light‐emitting diodes (CP‐OLEDs) achieve an external quantum efficiency (EQE) of 7.2% with a good exciton utilization (36%) and a moderate circularly polarized electroluminescence (CPEL) dissymmetry factor (gEL, 2.1 × 10−3). In addition, the CP‐HLCT molecule is sensitized by a thermally activated delayed fluorescence material, significantly ameliorating the efficiency of HLCT fluorescent CP‐OLEDs. Excellent performances of twofold maximum EQE (EQEmax) of 15.3% and 82% exciton utilization are obtained in the sensitized device, regarding an extremely low‐efficiency roll‐off of 2.6% at 1000 cd m−2 as well as CPEL with a gEL value of 2.0 × 10−3.
This work proposes the circularly polarized luminescence molecule based on a hybridized local and charge‐transfer (HLCT) chromophore through chiral perturbation, achieving excellent device performances of high exciton utilization and low‐efficiency roll‐off with a thermally activated delayed fluorescence sensitizer, which could pave the way to develop the novel CP‐HLCT materials and highly efficient circularly polarized organic light‐emitting diodes.
Chiral emitters capable of producing circularly polarized luminescence (CPL) with high dissymmetry factors (g) are crucial for circularly polarized organic light‐emitting diodes (CP‐OLEDs) and 3D ...display. Herein, sulfonyl binaphthalene is incorporated as both electron acceptor and chiral source into three pairs of thermally activated delayed fluorescence (TADF) enantiomers, (R/S)‐BPSTCZ, (R/S)‐BPSDMAC, and (R/S)‐BPSPXZ, for the first time, combining tert‐butylcarbazole, 9,9‐dimethyl‐9,10‐dihydro‐acridine and phenoxazine electron donors, respectively. These TADF compounds exhibit tunable emissions spanning from deep blue to green, accompanied by high photoluminescence quantum yields. Due to the large distorted angles caused by two sulfonyl units, all enantiomers exhibit pronounced CPL with |gPL| factors of up to 6.0 × 10−3 in doped films. The corresponding CP‐OLEDs display good performances with external quantum efficiencies of up to 28.5% and notable |gEL| factors of up to 8.8 × 10−3, surpassing most CP‐OLEDs based on chiral TADF materials.
By introducing the (R/S)‐sulfonyl binaphthalene units, three pairs of thermally activated delayed fluorescence enantiomers show emissions from deep blue to green with dissymmetry factors |gPL| of up to 6.0 × 10−3. The circularly polarized organic light‐emitting diodes (CP‐OLEDs) achieve external quantum efficiency of up to 28.5% and circularly polarized electroluminescence with |gEL| factors of up to 8.8 × 10−3.
Abstract Attaining phosphorescent materials with narrowband emission is crucial for advancing wide‐color‐gamut organic light‐emitting diode (OLED). Herein, a rigid modification strategy is introduced ...for iridium(III) complexes to achieve the narrowband red emission with negligible 0–1 peak. By introducing the rigid indolo3,2,1‐ jk carbazole (ICz) into the cyclometalated ligand, Ir(III) complexes, ICziq‐Ir and ICzqz‐Ir, exhibit pure red phosphorescence with emission peaks at 608 and 613 nm and full widths at half‐maximum (FWHMs) of 37 and 38 nm (0.12 and 0.13 eV) in toluene, respectively. Furthermore, the specific site modification of ICzqz‐Ir greatly suppresses the high‐frequency vibration of the structure, resulting in the narrowband photoluminescent spectrum close to the Gaussian distribution with superior color purity. The OLEDs utilizing ICziq‐Ir and ICzqz‐Ir demonstrate maximum external quantum efficiencies of 21.4 and 17.8% as well as mild efficiency roll‐off. Remarkably, the electroluminescence spectra exhibit similar narrowband red emission with FWHMs of 37 and 43 nm and CIE coordinates of (0.65, 0.35) and (0.66, 0.34), attesting to the excellent color purity of the phosphorescent OLEDs.
The development of efficient multi‐resonance thermally activated delayed fluorescence (MR‐TADF) materials with ultra‐narrowband emission presents an ongoing challenge. In this work, a carbazole‐fused ...dual‐boron embedded MR‐TADF framework is proposed, achieving three emitters, CFDBO, CFDBA, and CFDBCz, via one‐shot borylation with very high yields of over 70%. The emitters display ultra‐narrowband blue emission with peaks ranging from 452 to 479 nm and small full width at half maximum (FWHM) values of only 16–18 nm in dilute toluene solutions. Furthermore, the organic light‐emitting diode (OLED) incorporating CFDBO exhibits pure‐blue emission with a peak of 460 nm and Commission International de l'Eclairage coordinates of (0.14, 0.12). Meanwhile, OLEDs incorporating CFDBA/CFDBCz demonstrate remarkable performances with high external quantum efficiencies of 30.9%/32.4% and exceptionally slender FWHM values of 21/22 nm, representing outstanding performances among reported MR‐TADF materials.
Utilizing a novel carbazole‐fused dual‐boron embedded multi‐resonance thermally activated delayed fluorescence (MR‐TADF) architecture, three emitters demonstrate ultra‐narrowband emission ranging from pure‐blue to cyan‐green with full width at half maximums (FWHMs) of only 16–18 nm in dilute toluene. The corresponding organic light‐emitting diodes (OLEDs) display high external quantum efficiencies (EQEs) of up to 32.4% and exceptionally slender FWHM values of 21/22 nm, representing outstanding performances among reported MR‐TADF materials.
Two pairs of Pt(II) enantiomers ((RR)/(SS)-PyPt, ((RR)/(SS)-Py: N,N'-(1,2-diphenylethane-1,2-diyl)dipicolinamide; (RR)-P/M-QPt, ((RR)/(SS)-Q: ...N,N'-((1R,2R)-1,2-diphenylethane-1,2-diyl)bis(quinoline-2-carboxamide)) were synthesized, respectively, with good circularly polarized luminescence (CPL) and tunable dissymmetry factors (g) by molecular self-induction with (RR)/(SS)-1,2-diphenylethane-1,2-diamine as carbon chiral sources. In the (RR)-P-QPt and (SS)-M-QPt, specific P- and M-configurations were effectively induced from intrinsic chiral carbon centres (R or S), ingeniously avoiding the racemic mixture formation and chiral separation. Furthermore, the chirality originating from both chiral carbon centres and helicene-like structure improves the g factor significantly, which provides a new molecular design strategy for chiral Pt(II) enantiomers with good CPL properties.
Due to the chiral carbon centers as well as a helicence-like structure during the platinum coordination process, the Pt(II) enantiomers containing quinoline groups show improved g factor significantly without chiral separation process. Display omitted
