Stable deep blue organic light emitting diodes with CIE of y &lt; 0.10 based on quinazoline and carbazole units

Li, Bowen; Song, Xiangan; Jiang, Xi; Li, Zhiyi; Guo, Fengyun; Wang, Ying; Zhao, Liwei; Zhang, Yong

doi:10.1016/j.cclet.2019.06.033

Cited by 26 publications

(16 citation statements)

References 25 publications

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“…Figures c and S39 depict the lowest S 1 and T 1 state-level diagrams of 2PQ–PTZ and 4PQ–PTZ. Similar to our previous report on PQ-based emitters, ,, the lowest T 1 states of PQ-based emitters are the locally excited triplet states ( 3 LE) deriving from the PQ unit, which also indicated that the type of donors and molecular configuration have little effect on their T 1 energy in toluene solution. Therefore, 2PQ–PTZ and 4PQ–PTZ possess nearly identical T 1 state levels of 2.45 and 2.47 eV, respectively, to PQ moieties (2.48 eV) in toluene solution.…”

Section: Resultssupporting

confidence: 85%

“…2PQ−PTZ and 4PQ−PTZ were synthesized by the palladium-catalyzed Suzuki coupling reaction of chlorinated PQ (2PQ-Cl and 4PQ-Cl) and PTZ boronic acid pinacol ester (PTZ-Bpin), as shown in Scheme 1. 41 First, purification in a silica column was conducted, followed by sublimation under high vacuum condition. 2PQ−PTZ and 4PQ−PTZ show good solubilities in organic solvents such as dichlorobenzene, chloroform, toluene, chlorobenzene, etc.…”

Section: ■ Resultsmentioning

confidence: 99%

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Realizing Efficient Single Organic Molecular White Light-Emitting Diodes from Conformational Isomerization of Quinazoline-Based Emitters

Guo

et al. 2020

ACS Appl. Mater. Interfaces

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Single pure organic molecular white light emitters (SPOMWLEs) are of significance as a new class of material for white lighting applications; however, few of them are able to emit white electroluminescence from organic light-emitting diodes. Herein, donor−π–acceptor conjugated emitters, 2PQ–PTZ and 4PQ–PTZ, were designed and synthesized as SPOMWLEs for white light emission considering the distinct advantages of their conformation isomers. The coexistence of conformational isomers in 2PQ–PTZ, which is the first experimental evidence of the coexisting quasi-axial and quasi-equatorial conformers, provides ideal flexibility to obtain white light emission from their simultaneous and well-separated fluorescence and thermally activated delayed fluorescence. With these remarkable properties, a 2PQ–PTZ-based white light-emitting diode (LED) with a CIE of (0.32, 0.34) and color rendering index (CRI) of 89 is demonstrated. Further, the white organic light-emitting diode (OLED) of 2PQ–PTZ exhibits a high external quantum efficiency (EQE) of 10.1%, which is the reported highest performance among SPOMWLE-based OLEDs.

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Section: Resultssupporting

confidence: 85%

Section: ■ Resultsmentioning

confidence: 99%

Realizing Efficient Single Organic Molecular White Light-Emitting Diodes from Conformational Isomerization of Quinazoline-Based Emitters

Guo

et al. 2020

ACS Appl. Mater. Interfaces

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“…[22] The optical energy gap (E g ) of all emitters is estimated to be around 3.05 eV determined from the onset wavelengths of the absorption spectra. [23] Consistent with molecular design hypothesis, the energy level of S 1 obtained from the onset of FL spectra at 77 K is 3.11, 3.19 and 3.22 eV for AC-BO, QAC-BO and Cz-BO, respectively, indicating a continuous increase of S 1 levels via fine-tuning of heteroaromatic rigidity. The Ph spectra of AC-BO, QAC-BO, and Cz-BO all display characteristic local excitation featuring with similar energy levels, which can be attributed to the fluorene skeleton.…”

Section: Resultssupporting

confidence: 66%

Tuning Intramolecular Stacking of Rigid Heteroaromatic Compounds for High‐Efficiency Deep‐Blue Through‐Space Charge‐Transfer Emission

et al. 2022

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A series of ultrapure-blue thermally activated delayed fluorescence (TADF) emitters featuring through-space charge transfer (TSCT) have been constructed by close stacking between the donor and acceptor moieties in rigid heteroaromatic compounds. The obviously accelerated radiative transition of singlet excitons, the diminished vibrionic relaxation of ground and excited states, and the consequent reduced Stokes shift and the narrow emission are evident. The corresponding organic light-emitting diodes (OLEDs) based on AC-BO realize the best performance among all deep-blue TSCT-TADF emitters, with an external quantum efficiency (EQE max ) of 19.3 %. Furthermore, the OLEDs based on QAC-BO display an EQE max of 15.8 %, and achieve the first high-efficiency ultrapureblue TSCT-TADF material with an excellent Commission Internationale de L'Eclairage coordinate (CIE) of (0.145, 0.076) which perfectly matches the ultrapureblue CIE requirements (0.14, 0.08) defined by the National Television System Committee.

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“…It improves electrons injection inside the emitting layer. In the literature there are several materials used as ETL 40,41 ; • On the ETL the cathode electrode is deposited using a metallic thin film to finish the assembly of OLED structure, and, in this case, aluminum has been commonly used, because it is very easy to evaporate, due to its low melting point and good electrical conductivity 42,43 .…”

Section: Introductionmentioning

confidence: 99%

Different electrode anodes used in OLED devices Diferentes eletrodos anodos usados em dispositivos OLEDs

Santos

Fullenbach

Sparvoli

et al. 2021

RBAV

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Transparent conductive oxides (TCOs) known as indium tin oxide (ITO) and fluorine tin oxide (FTO) deposited on glass were compared by different techniques and also as anodes in organic light-emitting diode (OLED) devices with same structure. ITO produced at laboratory was compared with the commercial one manufactured by different companies: Diamond Coatings, Displaytech and Sigma-Aldrich, and FTO produced at laboratory was compared with the commercial one manufactured by Flexitec Company. FTO thin films produced at laboratory presented the lowest performance measured by Hall effect technique and also by I-V curve of OLED device with low electrical current and high threshold voltage. ITO thin films produced at laboratory presented elevated sheet resistance in comparison with commercial ITOs (approximately one order of magnitude greater), that can be related by a high number of defects as discontinuity of the chemical lattice or low crystalline structure. In the assembly of OLED devices with ITO and FTO produced at laboratory, neither presented luminances. ITO manufactured by Sigma-Aldrich company presented better electrical and optical characteristics, as low electrical resistivity, good wettability, favorable transmittance, perfect physicalchemical stability and lowest threshold voltage (from 3 to 4.5 V) for OLED devices.

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Stable deep blue organic light emitting diodes with CIE of y < 0.10 based on quinazoline and carbazole units

Cited by 26 publications

References 25 publications

Realizing Efficient Single Organic Molecular White Light-Emitting Diodes from Conformational Isomerization of Quinazoline-Based Emitters

Realizing Efficient Single Organic Molecular White Light-Emitting Diodes from Conformational Isomerization of Quinazoline-Based Emitters

Tuning Intramolecular Stacking of Rigid Heteroaromatic Compounds for High‐Efficiency Deep‐Blue Through‐Space Charge‐Transfer Emission

Different electrode anodes used in OLED devices Diferentes eletrodos anodos usados em dispositivos OLEDs

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