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Tunable Photophysical Properties of Thiophene Based Chromophores: Conjoined Experimental and Theoretical Investigation
摘要： In this paper we report synthesis and photophysical properties of six novel thiophene derivatives (ThD) with D-π-A structure. The subject of this work are three nitrophenyls (1) BT-Th-NO2 and three benzonitriles (2) BT-Th-CN, substituted at different positions of aromatic ring ((a) ortho-, (b) meta- or (c) para-). Dyes were obtained using simple three-step synthesis and their chemical structures were confirmed by 1H and 13C NMR, IR as well as high resolution mass spectrometry. The influence of positional isomerism on optical properties has been explored experimentally and theoretically. The photophysical properties were investigated using steady-state as well as time-resolved spectroscopy and the obtained results were supported by quantum-chemical calculations. TD-DFT calculations indicated that charge-transfer strength can be correlated with the observed optical properties. In addition, the influence of the acceptor position on photoluminescence spectra, fluorescence quantum yields and emission lifetimes was specified. We show that ThD optical properties can be tuned in wide spectral range by the change made in only single step of synthesis reaction.
关键词： push-pull chromophores,Thiophene derivatives,TD-DFT,quantum yield,charge transfer
更新于2025-11-19 16:46:39
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Novel hole blocking materials based on 2,6-disubstituted dibenzo[ <i>b</i> , <i>d</i> ]furan and dibenzo[ <i>b</i> , <i>d</i> ]thiophene segments for high-performance blue phosphorescent organic light-emitting diodes
摘要： Novel hole blocking materials (HBMs) based on 2,6-disubstituted dibenzo[b,d]furan and dibenzo[b,d]thiophene segments, 3,30,300,30 0 0-(dibenzo[b,d]furan-2,6-diylbis(benzene-5,3,1-triyl))tetrapyridine (26DBFPTPy) and 3,30,300,30 0 0-(dibenzo[b,d]thiophene-2,6-diylbis(benzene-5,3,1-triyl))tetrapyridine (26DBTPTPy), are successfully designed and synthesized for high-performance blue phosphorescent organic light-emitting diodes (PhOLEDs) for the first time. Computational simulation is used to investigate the optimal structure, orbital distribution, and physicochemical properties of both molecules. Thermal, optical, and electrochemical analysis shows that 26DBFPTPy and 26DBTPTPy possess high thermal stability, deep HOMO energy levels ((cid:2)7.08 and (cid:2)6.91 eV), and a high triplet energy (ET) (2.75 and 2.70 eV). Blue PhOLEDs with 26DBFPTPy or 26DBTPTPy as a hole blocking layer (HBL) exhibit a low turn-on voltage (3.0 V) and operating voltage (4.5 V) at 1000 cd m(cid:2)2. In addition, the blue PhOLEDs with 26DBFPTPy or 26DBTPTPy show superior external quantum e?ciencies (24.1 and 23.6%) and power e?ciencies (43.9 and 42.7 lm W(cid:2)1). They also show a very small e?ciency roll-o? of about 8.5% from 100 to 1000 cd m(cid:2)2. Furthermore, they exhibit improved lifetimes compared to the similarly designed HBL with a pyridine electron transport unit and a phenyl core structure.
关键词： dibenzo[b,d]furan,hole blocking materials,dibenzo[b,d]thiophene,blue phosphorescent organic light-emitting diodes,high-performance
更新于2025-11-14 15:32:45
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Photodegradation of thiophene over ZrO2–SiO2 nanoparticles: impact of copper decoration on their photocatalytic activity
摘要： A sol–gel technique was useful for the synthesis of zirconia–silica nanoparticles. Metallic copper has decorated zirconia–silica nanoparticles via photo-assisted deposition method, decorated copper mass percent was varied from 0.5, 1.0, 1.5, and 2.0 wt%. XRD results confirm that decoration of zirconia–silica nanoparticles by copper did not alert XRD pattern of zirconia–silica nanoparticles and there are no peaks for copper or copper oxide, due to high dispersion of copper above a surface of zirconia–silica nanoparticles. The decoration of zirconia–silica nanoparticles by copper was reduced band gap energy of zirconia–silica nanoparticles from 3.20 to 2.35 eV with 1.5 wt% Cu decoration. Photocatalytic oxidation of thiophene in presence of visible light was selected to measure the impact of metallic copper on photocatalytic activity of zirconia–silica nanoparticles. 1.5 wt% Cu-decorated zirconia–silica nanoparticles can degrade 100% of thiophene within 90 min.
关键词： ZrO2–SiO2,Sol–gel,Thiophene degradation,Cu decoration,Enhanced photocatalysis,Visible light
更新于2025-11-14 15:26:12
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Photocatalytic oxidative desulfurization and denitrogenation of fuels over sodium doped graphitic carbon nitride nanosheets under visible light irradiation
摘要： A cost-efficient photocatalytic oxidative denitrogenation and desulfurization system for fuels under visible light was developed on the basis of Na doped g-C3N4 nanosheets catalyst. The process adopted molecular O2 as oxidant to substitute for the expensive H2O2, and it adapted to the removal of small molecules of pyridine and thiophene. Na doped g-C3N4 nanosheets were obtained via a simple mixed-calcination pathway using NaCl as Na source. The structural, photophysical and chemical properties of the photocatalysts were characterized and compared to those of the original g-C3N4. It was verified that Na was successfully doped in the g-C3N4 lattice in a uniform chemical state. Moderate amount of Na doped in g-C3N4 generated the highly dispersed and porous nanosheets, which further improved the surface energy and reduce the recombination rate of electron-hole pairs. Na doped g-C3N4 exhibited enhanced performance simultaneously in the photocatalytic oxidative denitrogenation and desulfurization. The optimal catalyst obtained considerable removal efficiency for pyridine and thiophene, depending on its improved structural and photochemical properties by Na doping. A proposed mechanism revealed that the holes acted as the major active species for the denitrogenation and desulfurization, while the superoxide radicals originating from the combination of electron and O2 gave a promotion effect.
关键词： Pyridine,Sodium doping,Graphitic carbon nitride,Thiophene,Photocatalytic oxidation
更新于2025-09-23 15:23:52
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Towards the design of optically active thiophene S-oxides using quantum chemistry
摘要： The importance of axially chiral biaryls has risen steeply in the recent decades. This structural motif proved to be successful in catalytic asymmetric synthesis and the configuration of the biaryl axis is decisive for biological activity. A new approach for the atroposelective synthesis of biaryls would be through a cycloaddition between an enantiopure phenyl-substituted thiophene S-oxide and an alkyne. Importantly, the chiral center of the thiophene S-oxide needs to be stable enough to avoid pyramidal inversion during the cycloaddition. Since the racemization of thiophene monoxides has been scarcely investigated so far, we perform a thorough quantum chemical study on the inversion barriers of a large number of chiral thiophene S-oxide derivatives. Our main goal is to identify substitution patterns leading to stable atropisomers at room temperature. Appealingly, the role of the stereoelectronic effects and position of the substituents as well as the importance of aromaticity on the pyramidal inversion barrier is elucidated for the first time.
关键词： thiophene sulfoxides,axial chirality,DFT,enantiomerization,aromaticity
更新于2025-09-23 15:23:52
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Photocatalytic oxidation of thiophene over cerium doped TiO2 thin film
摘要： Samples of TiO2 and TiO2 doped with 2% and 8% cerium ions were prepared by a sol-gel method and used as photocatalysts for the oxidation of vaporized thiophene. X-ray diffraction patterns showed a mixed phase of anatase and rutile for TiO2, while 2%Ce/TiO2 and 8%Ce/TiO2 were dominated by the anatase phase. As seen in the transmission electron microscopy image, the particle size of Ce/TiO2 was about 10 nm which was smaller than the undoped TiO2. The extended x-rays absorption fine structures revealed the substitutional effect of cerium in the TiO2 structure. Cerium-doped TiO2 exhibited a smaller photocurrent compared to that of TiO2, which suggested the electrons were trapped by cerium ions. In situ diffuse reflectance infrared spectroscopy under UV irradiation and x-ray photoemission spectroscopy were used to investigate the photocatalytic oxidation of thiophene on the prepared catalysts. Doping of cerium ions in TiO2 resulted in an enhanced adsorption of thiophene on the catalyst surface. The oxidation products of carboxylic acid with small amounts of sulfate ions were observed. As seen from the infrared absorption spectrum, 2%Ce/TiO2 and 8%Ce/TiO2 exhibited higher photocatalytic activity than those of the undoped TiO2.
关键词： Thiophene oxidation,Thin film,Cerium,Photocatalysis,Titanium dioxide
更新于2025-09-23 15:23:52
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Synthesis and the effect of alkyl chain length on photochromic properties of diarylethene derivatives
摘要： A new class of photochromic diarylethenes bearing pyrrole and thiophene units with different length of alkyl chains at 2-position of thiophene rings have been synthesized. Their characteristics, including photochromism and fatigue resistance were investigated systematically, and each diarylethene derivative showed good photochromic properties whether in solution or in PMMA films. The alkyl group moiety was connected directly to the central cyclopentene ring as a heteroaryl unit and availably participated in photoisomerization reaction. And some properties, for example, the conversion ratio in the photostationary state(PSS) and the absorption coefficient of the ring-closed isomers in acetonitrile were significantly affected by the alkyl chain length. The results revealed that substituents of alkyl chain played an important role in the photoisomerization process of diarylethenes.
关键词： alkyl chain length,photochromism,pyrrole and thiophene units.,diarylethene
更新于2025-09-23 15:23:52
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Synthesis of 3,4-Biaryl-2,5-Dichlorothiophene through Suzuki Cross-Coupling and Theoretical Exploration of Their Potential Applications as Nonlinear Optical Materials
摘要： We report herein the efficient one-pot synthesis of 3,4-biaryl-2,5-dichlorothiophene derivatives (2a–2i) via a palladium-catalyzed Suzuki cross-coupling reaction. A series of thiophene derivatives were synthesized, starting from 3,4-dibromo-2,5-dichlorothiophene (1) and various arylboronic acids using Pd(PPh3)4 and K3PO4 with moderate to good yields. For further insights about the structure and property relationship, density functional theory (DFT) calculations were performed. A relaxed potential energy surface (PES) scan was performed to locate the minimum energy structure. A frontier molecular orbitals analysis was performed to explain the reactivity of all synthesized derivatives. As the synthesized derivatives had extended conjugations, therefore the first hyperpolarizability (βo) was calculated to investigate their potential as non-linear optical (NLO) materials and significant βo values were found for the 2b and 2g derivatives.
关键词： NLO,Pd (PPh3)4,thiophene,PES,density functional theory,Suzuki cross-coupling reaction
更新于2025-09-23 15:22:29
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Tetraphenylethylene Substituted Thienothiophene and Dithienothiophene Derivatives; Synthesis, Optical Properties and OLED Devices
摘要： Thieno[3,2-b]thiophene (TT) and dithieno[3,2-b;3,2-d]thiophene (DTT) have drawn an immense attention in the field of electronics and optoelectronics. In this work, first examples of TTs (TPE2-TT, TPE3-TT) and DTT (TPE2-DTT), having tetraphenylethylene (TPE) at the peripherals for aggregation induced emission (AIE) applications at OLEDs, were designed and synthesized by Suzuki coupling reaction. Their properties were investigated through experimental and computational studies, as well as X-ray diffraction and DFT-optimization. TPE2-TT produced an excellent device performance with a maximum luminance of 11620 cd m-2, a maximum current efficiency of 6.17 cd A-1 and maximum external quantum efficiency of 2.43%. Moreover, these synthetically easy accessible molecules had high thermal stability, which make them perfectly suitable for optical applications.
关键词： Tetraphenylethylene,Aggregation Induced Emission,Dithieno[3,2-b;3,2-d]thiophene,Thieno[3,2-b]thiophene,OLED
更新于2025-09-23 15:21:01
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Effects of the Isomerized Thiophene-Fused Ending Groups on the Performances of Twisted Non-Fullerene Acceptor-Based Polymer Solar Cells.
摘要： Recently, benefiting from the merits of small molecule acceptors (NFAs), polymer solar cells (PSCs) have achieved tremendous advances. From the perspective of the structural characteristics of the π-conjugated acceptor-donor-acceptor (A-D-A)-type of organic molecules, the backbone’s planarity, as well as the terminal groups and their substituents, have strong influences on the performances of the constructed NFAs. Through enlarging the dihedral angle of the conjugated main-chain of NFAs, a certain degree of enhanced photovoltaic parameters have been achieved. To further probe the influences of ending groups on the performances of nonplanar NFAs, we synthesized two new NFAs of i-cc23 and i-cc34 with isomerized thiophene-fused ending groups and twisted π-conjugated main-chain. Compared to the i-cc23 containing 2-(6-oxo-5,6-dihydro-4H-cyclopenta[b]thiophen-4-ylidene)malononitrile ending group, the 2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ylidene)malononitrile contained acceptor i-cc34 has a relatively higher molar extinction coefficient, bathochromic-shifted absorption spectrum, and deepened energy levels. When mixed with PBDB-T in solar cells, the i-cc23-based device achieved an excellent open-circuit voltage (VOC) of 1.10 V and a moderated power conversion efficiency of 7.34%. Although the VOC of i-cc34 related device was decreased to 0.96 V, the short-circuit current density and fill factor were improved, giving rise to enhanced efficiency of 9.51%. Apart from the distinct photovoltaic performances, the two isomers-based devices exhibit high radiative efficiency of 8×10-4, leading to a very small non-radiative loss of 0.19 V. Our results emphasize the importance of the isomerized thiophene-fused ending groups on the performances of nonplanar NFAs-based PSCs.
关键词： Twisted small molecular electron-acceptors,Thiophene-fused ending groups,Polymer solar cells,Isomerized end-groups,Non-radiative energy loss
更新于2025-09-23 15:21:01