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Triarylboryl-substituted carbazoles as bipolar host materials for efficient green phosphorescent organic light-emitting devices
摘要： Two novel bipolar host materials based on carbazole and triarylborane moieties, i.e. B-2CZ and m-B-CZ, are synthesized and characterized. The spatially crowded compound B-2CZ exhibits a high thermal stability (Td > 340 °C) compared to the reported triarylboryl carbazoles, presumably due to the highly compact architecture. As a result, phosphorescent Ir(ppy)3 combined with both the borylated compounds is selected to construct a host-guest system. Devices A (B-2CZ) and B (m-B-CZ) achieve peak efficiencies of 19.3% (69.1 cd/A and 88.1 lm/W) and 19.1% (66.1 cd/A and 77.2 lm/W), respectively. The respective turn-on voltages of devices A and B are recorded at 2.4 and 2.6 V, which are much lower than that of device with the benchmark host (mCP, 3.3 V). In addition, at a higher practical luminance of 100 cd/m2 (1000 cd/m2), the external quantum efficiencies of devices A and B are still preserved at 19.1% (17.3%) and 18.2% (13.0%) with the mitigated efficiency drops of 1% (10%) and 5% (32%), suggesting the promising advantage for realizing efficient phosphorescent organic light-emitting devices.
关键词： Carbazole,Triarylborane,Bipolar host,Phosphorescent organic light-emitting devices
更新于2025-09-10 09:29:36
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Red emitting coumarin based 4, 6-disubstituted-3-cyano-2-pyridones dyes – Synthesis, solvatochromism, linear and non-linear optical properties
摘要： New coumarin fluorescent based D-π-A-π-D dyes are synthesized and studied for their optical properties. Their show absorption and emission respectively are in the range of 471-504 nm and 506-550 nm. Viscosity induced emission intensity increase is examined with 0-100% PEG-400 in ethanol MLK 4 is good FMR as compared to the MLK 1-3 due to the presence of extra-π-conjugation. FMO analysis and Generalised Mulliken Hush analysis show a strong interaction of molecular charge transfer characteristics. The first (α), second (β) and third (γ) order polarizability of MLK 1-4 are calculated by the solvatochromic technique and corroborated by DFT calculations using CAM-B3LYP/6-31G(d) method. The outcomes found by solvatochromic technique are compared theoretically with DFT using B3LYP/6-31G(d) and CAM-B3LYP/6-31G(d) methods. These methods reveal that, CAM-B3LYP/6-31G(d) carry out for calculating α, β, γ. Photophysical data was also applied to establish the ground and excited state dipole moment ratio using Bakhshiev, Bilot-Kawski, and Liptay functions. Liptay function shows better correlations than the other two functions for all dyes.
关键词： Viscosity sensor,TD-DFT,Coumarin,NLO properties,Carbazole,Intramolecular charge transfer
更新于2025-09-10 09:29:36
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High-contrast mechanofluorochromism and acidochromism of D-π-A type quinoline derivatives
摘要： New D-π-A type quinoline derivatives (CbzVQ and TPAVQ) were synthesized via Knoevenagel condensation reactions. They exhibited reversible high-contrast mechanofluorochromic (MFC) behavior under grinding/fuming treatment. Taking CbzVQ as an example, its fluorescence could be switched from blue to greyish green by grinding the as-synthesized sample into ground powders, and the fluorescence emission was red-shifted from 449 nm (with shoulders at 475 nm and 520 nm) to 578 nm (with shoulders at ca. 450 nm and 500 nm). Such large shift of the maximal emission peak during MFC processes was rare reported. In addition, the casting films of CbzVQ and TPAVQ emitted blue and green light, respectively, which was turned to red rapidly induced by TFA (trifluoroacetic acid) vapor. Moreover, the emission could be recovered stimulated by TEA (triethylamine) vapor, so the quinoline derivatives exhibited reversible fluorescent sensory properties. TPAVQ showed better performance in the detection of TFA vapor than CbzVQ due to the strong electron-donating ability of triphenylamine compared with carbazole. The detection limit and the decay time of TPAVQ towards TFA vapor were 163 ppb and 0.22 s, respectively. Apparently, the D-π-A type quinoline derivatives are candidates as multi-stimuli responsive fluorescent materials.
关键词： carbazole,quinolines,mechanofluorochromism,acidochromism,triphenylamine
更新于2025-09-10 09:29:36
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A review on low-molar-mass carbazole- based derivatives for organic light emitting diodes
摘要： Organic light emitting diodes (OLEDs) have attracted a great deal of attention within academia and industry because of their potential applications in flat panel displays and solid-state lighting technologies. Among all low-molar-mass derivatives under investigation in OLEDs field, carbazole-based materials have been studied at length for their interesting physical properties, including good charge injection and transport, electro-luminescence, improved thermal and morphological stabilities as well as film forming properties. In addition, the relatively high triplet energy level of some substituted carbazoles makes them suitable candidates to design hosts for wide bandgap triplet emitters such as blue dopants. The article is written from structural organic chemist's point of view and is divided in several parts: V-shaped 3(2)-substituted carbazoles and derivatives with 9-carbazolyl rings, star-shaped 3,6(2,7)-substituted carbazoles and branched twin derivatives containing (di)arylcarbazolyl fragments.
关键词： Amorphous material,Ionization potential,Glass transition temperature,Organic light emitting diode,Substituted carbazole,Hole transporting material
更新于2025-09-09 09:28:46
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Carbazole/Indole-Substituted Bianthracene Derivatives for Blue Organic Light Emitting Diodes
摘要： As an effort to search efficient blue emitters for OLEDs, we synthesized two blue fluorescent materials based on carbazole- and indole-substituted bianthracene. To investigate their electroluminescent (EL) properties, multilayered OLEDs with the following sequence; indium-tin-oxide (ITO)/N,N (cid:3)-di(1-naphthyl)-N,N (cid:3)-diphenyl-(1,1(cid:3)-biphenyl)-4,4(cid:3)-diamine (NPB) (50 nm)/Blue emitting materials (30 nm)/bathophenanthroline (Bphen) (30 nm)/8-hydroxyquinolinolate-lithium (Liq) (2 nm)/Al (100 nm) were fabricated using these materials as emitters. Particularly, a device using 9-(4-(10-(10-(4-(9H-carbazol-9-yl)phenyl)anthracen-9-yl)anthracen-9-yl)phenyl)-9H-carbazole exhibited the efficient blue emission with a luminous efficiency, a power efficiency, an external quantum efficiency, and CIE coordinates of 2.49 cd/A, 1.07 lm/W, 2.30% at 20 mA/cm2, and (0.15, 0.12) at 8.0 V, respectively. This study demonstrates that arylamine-substituted bianthracene derivatives have the excellent properties for blue emitting materials for OLEDs.
关键词： Blue OLED,Carbazole,Indole,Bianthracene,Fluorescence
更新于2025-09-09 09:28:46
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Binding Study of the Fluorescent Carbazole Derivative with Human Telomeric G-Quadruplexes
摘要： The carbazole ligand 3 was synthesized, characterized and its binding interactions with human telomeric (22HT) G-quadruplex DNA in Na+ and K+-containing buffer were investigated by ultraviolet-visible (UV-Vis) spectrophotometry, fluorescence, circular dichroism (CD) spectroscopy, and DNA melting. The results showed that the studied carbazole ligand interacted and stabilized the intramolecular G-quadruplexes formed by the telomeric sequence in the presence of sodium and potassium ions. In the UV-Vis titration experiments a two-step complex formation between ligand and G-quadruplex was observed. Very low fluorescence intensity of the carbazole derivative in Tris HCl buffer in the presence of the NaCl or KCl increased significantly after addition of the 22HT G4 DNA. Binding stoichiometry of the ligand/G-quadruplex was investigated with absorbance-based Job plots. Carbazole ligand binds 22HT with about 2:1 stoichiometry in the presence of sodium and potassium ions. The binding mode appeared to be end-stacking with comparable binding constants of ~105 M?1 as determined from UV-Vis and fluorescence titrations data. The carbazole ligand is able to induce formation of G4 structure of 22HT in the absence of salt, which was proved by CD spectroscopy and melting studies. The derivative of carbazole 3 shows significantly higher cytotoxicity against breast cancer cells then for non-tumorigenic breast epithelial cells. The cytotoxic activity of ligand seems to be not associated with telomerase inhibition.
关键词： carbazole derivative,telomerase,biological activity,G-quadruplex,telomere,spectroscopy
更新于2025-09-09 09:28:46
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Vinyl-Linked Cyanocarbazole-Based Emitters: Effect of Conjugation and Terminal Chromophores on the Photophysical and Electroluminescent Properties
摘要： A series of carbazole-based dyes functionalized with different auxochromes via vinyl linker have been synthesized and characterized. A progressive shift in the absorption maximum is observed as the conjugation and electron-donating nature of chromophore increases. Dyes containing electron-releasing terminal groups such as triphenylamine and carbazole exhibited positive emission solvatochromism attributable to an induced intramolecular charge transfer from triphenylamine/carbazole donor to cyano acceptor. The superior electroluminescence performance of disubstituted dyes demonstrates the role of an additional cyanocarbazole in achieving balanced charge transport compared to monosubstituted analogues. In addition, the electroluminescence performance of the dyes exhibited trends attributable to the electron richness of the linker/terminal chromophore. Thus, the carbazole-based derivatives displayed better electroluminescence efficiency than the analogous fluorene derivatives. Similarly, 2,7-substituted carbazole derivative exhibited better performance than the 3,6-substituted carbazole derivative. A doped electroluminescent device containing 3 wt % tricarbazole derivative showed blue emission with a high external quantum efficiency of 5.3% at a practical brightness of 1000 cd/m2.
关键词： OLED,vinyl linker,carbazole,electroluminescent properties,photophysical properties
更新于2025-09-09 09:28:46
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Novel blue light emitting poly(arylene ether)s under the influence of guest concentrations in host-guest systems: Synthesis, electrochemical and photophysical properties
摘要： A series of novel blue (poly-arylene ether)s polymers based on the anthracene derivatives as the guest material, and the hole transfer carbazole dervatives as the host material have been successfully synthesized by nucleophilic polycondensation. The obtained polymers exhibited high glass transition temperatures (Tg) ranging from 180 to 255 °C and decomposition temperatures (Td) ranging from 358 to 477 °C. Number average molecular weight (Mn) ranged from 3.12 × 104 to 7.20 × 104, and polydispersity indices (PDI) ranged from 1.25 to 2.10. Cyclic voltammetry investigation inform that these polymers possess LUMO energy levels ranging from ?2.29 to ?2.46 eV. In case of thin films state, all the polymers emit blue luminance with the emission maximum peaks ranging from 442 to 448 nm. The electroluminescent devices based on the these polymers with a configuration of ITO/PEDOT:PSS/polymer/TmPyPB/LiF/Al emitted blue light with CIE chromaticity coordinates of (0.15, 0.10).
关键词： Polymer Light Emitting Diodes,Ether Linkage,Blue Light Emission,Anthracene,Carbazole
更新于2025-09-04 15:30:14
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Synthesis and investigation of charge transport properties in adducts of hole transporting carbazole derivatives and push-pull azobenzenes
摘要： In order to investigate the viability of a material design for bulk heterojunction (BHJ) organic solar cells, where hole transporting group is bound to the donor moiety, we report the synthesis and charge transport characteristics of 3-(diphenylamino)carbazolyl- functionalized derivatives of 2-(4-((4-(dimethylamino)phenyl)diazenyl)benzylidene)-1H-indene-1,3-dione (DMAAzi) chromophore. Three different bounding configurations were examined in these adducts. Additionally, a trityl- functionalized derivative of DMAAzi was prepared and used for comparison purposes. All of the synthesized materials form thin amorphous films from volatile organic solvents and exhibit glass transition temperatures in the range from 89 °C to 124 °C. The molecular ionization energy and electron affinity energy levels in thin films were measured. Photo-induced time of flight (ToF) method was used in to determine charge carrier drift mobilities. It was found out that the formation of deep charge trap states with local energies at approximately 0.60 - 0.78 eV takes place and has a considerable negative effect on the hole drift mobility of the investigated compounds.
关键词： charge transport,molecular glasses,carbazole,organic photovoltaics,azobenzene dyes
更新于2025-09-04 15:30:14