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A bipolar deep blue-emitting fluorescent material based on imidazole and triphenylamine for efficient non-doped OLEDs
摘要： A bipolar deep blue-emitting fluorescent material, 1-(4-tert-butyl phenyl)-2-[4-(N,N- diphenyl)phenyl]-4,5-diphenyl-1H-imidazole (TPA-PIM) has been designed and synthesized for efficient blue organic light-emitting diodes (OLEDs). The photophysical, thermal and electrochemical properties of TPA-PIM are investigated. TPA-PIM possesses high thermal stabilities with decomposition temperature of 396 °C and shows a strong deep-blue emission at 407 nm in N, N-dimethylformamide (DMF) solution. Single-carrier devices are fabricated to show that TPA-PIM has good bipolar characteristics. The non-doped fluorescent OLEDs using TPA-PIM as emitter exhibited stable and efficient deep-blue emissions with the CIE coordinates of (0.16, 0.09), the maximum luminance of 1392 cd m?2 and the maximum current efficiency of 2.60 cd A?1.
关键词： Triphenylamine,Blue light-emitting materials,Bipolar materials,Imidazole,Non-doped OLEDs
更新于2025-11-19 16:56:42
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Electrochromism in Electropolymerized Films of Pyrene-Triphenylamine Derivatives
摘要： Two star-shaped multi-triphenylamine derivatives 1 and 2 were prepared, where 2 has an additional phenyl unit between a pyrene core and surrounding triphenylamine units. The oxidative electropolymerization of 1 and 2 occurred smoothly to give thin films of polymers P1 and P2. The electrochemistry and spectroelectrochemistry of P1 and P2 were examined, showing two-step absorption spectral changes in the near-infrared region. The electrochromic properties, including contrast ratio, response time, and cyclic stability of P1 and P2 were investigated and compared. Thin film of P2 displays slightly better electrochromic performance than P1, with a contrast ratio of 45% at 1475 nm being achieved.
关键词： triphenylamine,near-infrared,electrochemistry,electrochromism,electropolymerization
更新于2025-09-23 15:22:29
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Thermal, spectroscopic, electrochemical, and electroluminescent characterization of malononitrile derivatives with triphenylamine structure
摘要： Three push-pull molecules with linear, quadrupolar and tripodal arrangements, consisting of triphenylamine (electro-donor) substituted with malononitrile groups (electro-acceptor), were synthesized with high yield by a simple procedure. Impact of the number of malononitrile substituents on optoelectronic properties was investigated with cyclic voltammetry, absorption and emission spectroscopy, as well as density functional theory calculation. The derivatives formed amorphous materials and exhibited low energy band gaps ranging from 2.06 to 2.49 eV. UV–Vis absorption and photoluminescence emission spectra were investigated in solutions (CHCl3, NMP) and in solid-state as thin films and two kinds of blends (with PMMA and PVK:PBD). Quantum yield of photoluminescence was dependent on the molecule structure, solvent, and solid-state layer formulation. The compounds exhibited high photoluminescence quantum yield in the range of 15–42% and 12–59% in solid-state as film and blend with PMMA (1 wt%), respectively, being promising for applications in light emitting diodes. The diodes with active layer consisting of neat derivatives and compounds molecularly dispersed in PVK:PBD (50:50 wt%) matrix showed orange and green electroluminescence.
关键词： Triphenylamine,Photoluminescence,Electrochemistry,Malononitrile,Electroluminescence
更新于2025-09-23 15:21:21
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Theoretical study of Da??Aa?2a????a??A/Da????a??Aa?2a????a??A triphenylamine and quinoline derivatives as sensitizers for dye-sensitized solar cells
摘要： We have designed four dyes based on D–A0–p–A/D–p–A0–p–A triphenylamine and quinoline derivatives for dye-sensitized solar cells (DSSCs) and studied their optoelectronic properties as well as the e?ects of the introduction of alkoxy groups and thiophene group on these properties. The geometries, single point energy, charge population, electrostatic potential (ESP) distribution, dipole moments, frontier molecular orbitals (FMOs) and HOMO–LUMO energy gaps of the dyes were discussed to study the electronic properties of dyes based on density functional theory (DFT). And the absorption spectra, light harvesting e?ciency (LHE), hole–electron distribution, charge transfer amount from HOMO to LUMO (QCT), D index, HCT index, Sm index and exciton binding energy (Ecoul) were discussed to investigate the optical and charge-transfer properties of dyes by time-dependent density functional theory (TD-DFT). The calculated results show that all the dyes follow the energy level matching principle and have broadened absorption bands at visible region. Besides, the introduction of alkoxy groups into triarylamine donors and thiophene groups into conjugated bridges can obviously improve the stability and optoelectronic properties of dyes. It is shown that the dye D4, which has had alkoxy groups as well as thiophene groups introduced and possesses a D–p–A0–p–A con?guration, has the optimal optoelectronic properties and can be used as an ideal dye sensitizer.
关键词： alkoxy groups,thiophene group,density functional theory,dye-sensitized solar cells,D–A0–p–A/D–p–A0–p–A,triphenylamine,quinoline derivatives,time-dependent density functional theory,optoelectronic properties
更新于2025-09-23 15:21:01
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Efficient non-doped blue fluorescent OLEDs based on bipolar phenanthroimidazole-triphenylamine derivatives
摘要： Blue organic emissive materials are still the most important bottlenecks for the development of organic light-emitting diodes (OLEDs). To enrich the material library, herin, three bipolar phenanthroimidazole derivatives, namely MePPIM-TPA, ClPPIM- TPA and BuPPIM-TPA, are synthesized using triphenylamine as electron-donor and phenanthroimidazole as the electron-acceptor. The photophysical, thermal and electrochemical properties of three compounds are investigated with high decomposition temperature up to 350 °C, and strong blue emission. Single-carrier devices are fabricated to show that three compounds have good bipolar carrier transport characteristic. The non-doped fluorescent OLEDs devices using three compounds as emitting layers are fabricated among which the devices based on MePPIM-TPA achieved the maximum luminance of 1743 cd/m2, the maximum external quantum efficiency (EQE) of 2.99% which is relatively comparable to commonly used blue emitters.
关键词： Non-doped OLEDs,Bipolar characteristic,Triphenylamine,Fluorescent materials,Phenanthroimidazole
更新于2025-09-23 15:19:57
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The influence of molecular structure on collision radius for optical sensing of molecular oxygen based on cyclometalated Ir( <scp>iii</scp> ) complexes
摘要： Three triphenylamine (TPA) substituted cyclometalated Ir(III) complexes IrA1, IrA2, and IrA3 based on Ir(ppy)3 were synthesized and applied as phosphorescent probes for the monitoring of molecular oxygen. The phosphorescence intensity of all the Ir(III) complexes in tetrahydrofuran (THF) was gradually quenched with an increase of oxygen concentration. The increase of TPA substituents on the meta-position of 2-phenylpyridine (IrA1-IrA3) gradually improved the oxygen sensitivity of cyclometalated Ir(III) complexes. IrA3 showed the highest oxygen sensitivity in THF with a KappSV of 204.8 bar?1 and a limit of detection (LOD) of 0.27 mbar. The relationship between molecular structure and the collision radiuses (s) of all the Ir(III) complexes has been investigated on the basis of the Demas model and the fundamental expression of luminescence quenching systems by oxygen. The ratio of collision radiuses are sIrA1/sIr(ppy)3 = 1.27 ± 0.05, sIrA2/sIr(ppy)3 = 1.72 ± 0.10, and sIrA3/sIr(ppy)3 = 2.13 ± 0.07, respectively. The introduction and increase of TPA substituents can obviously increase the collision radiuses of cyclometalated Ir(III) complexes which leading to potential oxygen sensitivity. And the incremental effect of collision radiuses caused by the introduction of TPA substituents resulted in outstanding oxygen sensitivity of IrA3. The results demonstrate for the first time evidence between molecular structure and oxygen sensitivity of the emitters for optical sensing.
关键词： optical sensing,collision radius,molecular oxygen,triphenylamine substituents,cyclometalated Ir(III) complexes
更新于2025-09-19 17:15:36
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New Triphenylamine-Based Oligomeric Schiff Bases Containing Tetraphenylsilane Moieties in the Backbone
摘要： Three new triphenylamine-based oligomeric Schiff bases (polySB1, polySB2 and polySB3) containing tetraphenylsilane core (TPS-core) in the main chain were obtained from TPS-core-based diamines and bis(4-formylphenyl)phenylamine by a high-temperature polycondensation reaction. These new oligomers were structurally characterized by FT-IR, NMR and elemental analysis. All polySBs were highly soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene. Samples showed moderate molecular average molecular weight (Mw) and a high thermal stability above 410 °C. Likewise, polySBs showed absorption near 400 nm in the UV-vis range and photoluminescence. The HOMO levels and band-gap values were found in the ranges of ?6.06 to ?6.18 eV and 2.65–2.72 eV, respectively. The lowest band-gap value was observed for polySB2, which could be attributed to a more effective π-conjugation across the main chain. The results suggest that silicon-containing polySBs are promising wide-band-gap semiconductors materials for optoelectronic applications.
关键词： optoelectronic applications,tetraphenylsilane,oligomeric Schiff bases,triphenylamine
更新于2025-09-19 17:15:36
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Introduction of Multifunctional Triphenylamino Derivatives at the Perovskite/HTL Interface to Promote Efficiency and Stability of Perovskite Solar Cells
摘要： Surface passivation is a widely used approach to promote the efficiency and stability of perovskite solar cells (PSCs). In the present project, a series of new organic surface passivation molecules, which contain the same triphenylamino group with the hole transfer material of PSCs has been synthesized. These new passivation molecules are supposed to have both “carrier transfer” capability and “defect passivation” potential. We find that by using N-((4-(N,N,N-triphenyl)phenyl)ethyl)ammonium bromide (TPA-PEABr) as a surface passivation molecule, the efficiency of the PSCs can be improved from 16.69% to 18.15%, mainly due to an increased Voc (1.09 V compared with 1.02 V in control devices). The increased Voc is due to the reduced surface defect density and a better alignment for the related energy levels after introducing the TPA-PEABr molecules. Moreover, the stability of the PSCs can be significantly improved in TPA-PEABr passivated devices due to the hydrophobic nature of TPA-PEABr. Our results successfully demonstrate that passivation of the perovskite surface with a carefully designed multiple functional small organic molecule should be a useful approach for more stable PSCs with high efficiency.
关键词： Stability,Surface passivation,Perovskite solar cell,Triphenylamine derivative,Energy level alignment
更新于2025-09-19 17:13:59
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Fused tetraphenylethylene-triphenylamine for efficient hole transporting materials in perovskite solar cells
摘要： Fused tetraphenylethylene-based hole transporting material shows higher power conversion efficiency and better stability compared with that of non-fused counterpart, and former molecule even outperforms the conventional spiro-OMeTAD.
关键词： power conversion efficiency,perovskite solar cells,hole transporting materials,tetraphenylethylene,triphenylamine
更新于2025-09-19 17:13:59
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Enhanced photovoltaic performance of quinoxaline-based small molecules through incorporating trifluoromethyl substituents
摘要： Two D-A-D type quinoxaline-based small molecules have been synthesized by Suzuki coupling reaction for solution-processable organic photovoltaic cells (OPVs). The electron-donating triphenyl-amine was connected to both ends of an electron-withdrawing 2,3-diphenylquinoxaline core through thiophene bridge to produce QxTPA. In addition, QxCF3TPA was formed by introducing strong electron-withdrawing trifluoromethyl (CF3) groups into the para-position of the phenyl ring at the 2,3-position of quinoxaline core in QxTPA to explore their effect on the various properties of small molecules. The finding revealed the significant contributions of CF3 substituents in enhancing the photovoltaic performances of OPVs with QxCF3TPA compared to the reference case with QxTPA.
关键词： Small molecules,triphenylamine,trifluoromethyl,organic photovoltaic cell,2,3-diphenylquinoxaline
更新于2025-09-19 17:13:59