- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Solar cells sensitized with porphyrin dyes with a carbazole donor: The effects of an auxiliary benzothiadiazole acceptor and bulky substituents on the donor
摘要： Three porphyrin sensitizers XW54–XW56 containing a carbazole donor have been designed and synthesized by introducing a benzothiadiazole (BTD) unit as the auxiliary electron acceptor to extend the absorption spectra and/or bulky dihexyloxyphenyl groups into the carbazole unit to suppress dye aggregation and improve the photovoltage (Voc). The BTD unit incorporated in XW54 obviously broadens and red-shifts the absorption threshold to ca. 700 nm, as compared with that of 650 nm observed for XW1. Thus, XW54 exhibits a much broader monochromatic photon-to-electron conversion efficiency (IPCE) spectrum with an extremely red-shifted onset wavelength of 780 nm, resulting in a photocurrent density (Jsc) of 11.60 mA cm?2, higher than that of XW1. Unfortunately, the Voc value was decreased owing to the more severe dye aggregation caused by the large conjugation framework induced by the presence of the BTD unit. As a result, XW54 shows an efficiency of 6.26%, slightly higher than that of 6.11% obtained for XW1. On the other hand, with the bulky dihexyloxyphenyl donor groups introduced to XW55, a highest Voc of 860 mV was achieved, which can be ascribed to the efficient prevention of charge recombination and suppression of dye aggregation. Thus, XW55-based cells exhibit an improved e?ciency of 6.60%. On the basis of XW54 and XW55, two bulky dihexyloxyphenyl groups and a BTD unit were simultaneously introduced to XW56, affording a highest efficiency of 7.03%, with the Jsc and Voc values of 12.5 mA cm?2 and 785 mV, respectively. These results compose a novel approach for developing e?cient dye-sensitized solar cells (DSSCs) by simultaneously introducing bulky dihexyloxyphenyl groups and a benzothiadiazole unit, which may synergistically broaden the absorption spectra and suppress the dye aggregation, resulting in improved photocurrent and photovoltage.
关键词： Dye-sensitized solar cells,Sensitizers,Porphyrin,Bulky groups,Carbazole
更新于2025-11-19 16:56:42
-
Aggregation-induced emission (AIE)-active highly emissive novel carbazole-based dyes with various solid-state fluorescence and reversible mechanofluorochromism characteristics
摘要： Three new carbazole-based fluorescent molecules 1-3 functionalized with tetraphenylethene have been successfully synthesized, and these compounds have high thermal stability, and they exhibited different fluorescence in solid states with the superior luminescence quantum yields of 99.04% (1), 98.90% (2) and 39.83% (3). Their aggregation-induced behaviors were explored by the study of photoluminescence spectroscopy. The results showed that luminogens 1-3 exhibited remarkable aggregation-induced emission effect. Furthermore, their distinct mechanical stimulus-responsive fluorescence characteristics were also surveyed by solid-state photoluminescence spectroscopy. Interestingly, the various emitting colors of these luminogens could be changed into the same green, and the repeatabilities of their mechanochromic luminescence behaviors were outstanding, and the powder X-ray diffraction results indicated that the reversible conversion from a crystalline to an amorphous state was responsible for the obvious mechanofluorochromism phenomena of compounds 1-3. This work will be valuable for the exploitation of mechanical-force sensors with typical aggregation-induced emission feature.
关键词： Carbazole,Mechanofluorochromism,Tetraphenylethene,Aggregation-induced emission,Different fluorescence,High thermal stability
更新于2025-11-14 15:23:50
-
Realizing efficient bipolar deep-blue light-emitting poly(2,7-carbazole) derivatives by suppressing intramolecular charge transfer
摘要： Two series of twisted bipolar poly(2,7-carbazole) derivatives, namely PCz-37RSOs and PCz-28SOs, were synthesized by introducing electron-deficient 2,8-dioctyl-dibenzothiophene-S,S-dioxide-3,7-diyl (37RSO) and dibenzothiophene-S,S-dioxide-2,8-diyl (28SO) unit into poly(9-heptadecanyl-2,7-carbazole) (PCz) backbone, respectively. The incorporation of electron-withdrawing 37RSO and 28SO into PCz backbone decreased effective conjugation length, and further restrained charge transfer effect existed in dipolar system, simultaneously, the balanced charge carrier injection/transportation were realized due to the electrophilicity of SO unit. Consequently, the resulting polymers showed hypsochromic shift and narrowed emission spectra regarding to PCz-37SOs that contains linear SO unit in main chain, and exhibited balanced hole/electron fluxes with respect to PCz in the range of 0–10 V. The single-layer devices based on resulting bipolar polymers exhibited excellent electroluminescent spectra stability in the current densities from 100 to 400 mA cm?2, and displayed deep blue electroluminescence spectra with the Commission Internationale de L’ Eclairage (CIE) of (0.16, 0.07) for PCz-37RSO5 and (0.16, 0.09) for PCz-28SO5. The superior device performance was achieved with the maximum luminous efficiency (LEmax) of 2.69 cd A?1 for PCz-28SO20, which obviously outperformed that of 0.24 cd A?1 for PCz. These results indicated that twisted molecular structure design is a promising strategy for efficient deep blue light-emitting polymers.
关键词： Poly(2,7-carbazole),Bipolar,Twisted structure,Blue light-emitting polymers,Charge transfer effect
更新于2025-09-23 15:22:29
-
A novel dicationic Quinoline-Carzole fluorescent probe：Preparation and labeling of <i>Microthrix parvicella</i>
摘要： A novel dicationic Quinoline-Carbazole fluorescent probe with hydrophobic long-chain alkane was designed and synthesized based on the property of Microthrix parvicella (M. parvicella) in situ utilizing long-chain fatty acids (LCFA) in the activated sludge system. 1H NMR spectrum, ultraviolet-visible (UV-Vis) absorption spectra, and fluorescent spectra analysis demonstrated that the probe was successfully obtained. The probe had a large stokes-shift ranging from 102 to 144nm in different solvents, which were benefit for the fluorescent labeling properties. The labeling experiment indicated that the prepared probe could absorb onto the surface of M. parvicella through hydrophobic bond. Much stronger yellow fluorescence of M. parvicella was observed at the concentration of 1.0×10-5mol/L when compared with the zooglea, which makes it easy to distinguish M. parvicella from the zooglea. In addition, the photostability of the probe was also investigated, and the result showed that the probe was quite stable in a long period of time. All the results indicated that the prepared probe was suitable for the labeling of M. parvicella.
关键词： Dicationic Quinoline-Carbazole,fluorescent probe,Characterization,labeling,Microthrix parvicella
更新于2025-09-23 15:22:29
-
Trap-Controlled White Electroluminescence From a Single Red-Emitting Thermally Activated Delayed Fluorescence Polymer
摘要： Single white-emitting polymers have been reported by incorporating the second-generation carbazole dendron into the side chain of a red-emitting thermally activated delayed ?uorescence (TADF) polymer. Due to the prevented hole trap effect, in this case, excitons can be generated simultaneously on the polymeric host and the red TADF dopant to give a dual emission. Consequently, a bright white electroluminescence is achieved even at a dopant loading as high as 5 mol.%, revealing a maximum luminous ef?ciency of 16.1 cd/A (12.0 lm/W, 8.2%) and Commission Internationale de l’Eclairage (CIE) coordinates of (0.42, 0.32). The results clearly indicate that the delicate tuning of charge trap is a promising strategy to develop ef?cient single white-emitting polymers, whose low-band-gap chromophore content can be up to a centesimal level.
关键词： carbazole dendron,thermally activated delayed ?uorescence (TADF),dual emission,charge trap,single white-emitting polymers
更新于2025-09-23 15:21:01
-
Carbazole-modified polyphenylene ether as host materials for high efficiency phosphorescent organic light-emitting diodes
摘要： Two novel polymeric hosts called PPO-Cz and PPO-3Cz for solution-processed green phosphorescent organic light-emitting devices have been designed and synthesized by incorporating electron-donor carbazole units with polyphenylene ether. In order to simplify the synthesis route and save cost, we attached the classic carbazole units directly to the side chain of the polyphenylene ether. This molecular design endows these two polymeric hosts with good thermal stability and high triplet energy levels. PPO-Cz- and PPO-3Cz-based emissive-layer green phosphorescent organic light-emitting diodes were fabricated with simplified device configuration by solution-processed using Ir(mppy)3 as a dopant. These devices exhibited lower turn on voltages. Moreover, the PPO-3Cz-based solution processed device showed maximum current efficiency and external quantum efficiency of 31.8 cd/A and 9.3%, respectively. This result demonstrated that the newly synthesized, polymeric hosts were advantageous for fabrication of highly efficient green phosphorescent organic light-emitting diodes.
关键词： Organic light emitting diode,Polyphenylene ether,Modify,Carbazole,Polymeric host
更新于2025-09-23 15:21:01
-
Design, Synthesis and Photophysical Analysis of New Unsymmetrical Carbazole-Based Dyes for Dye-Sensitized Solar Cells
摘要： The molecular design, synthesis, and characterization of di-anchoring carbazole-based dyes (Car-Cy, Car-Amin, and Car-Mal) with A-π-D-π-A-π-A structure as materials for dye-sensitized solar cells applications (DSSCs) are reported. The electron-rich carbazole moiety in the structure of synthesized dyes is connected with acceptor/ or anchoring groups (cyanoacetic acid, 4-aminobenzoic acid, and malonic acid) and π-spacers (vinylene and cynovinyl thiophene). Electronic characteristics and molecular geometry of the sensitizers were optimized using Density Functional Theory (DFT), and the influence of dye structure on their photovoltaic performances was studied. Among the synthesized dyes in this research, Car-Amin dye presents a better photovoltaic performance as a sensitizer in the constructed device, with a power conversion efficiency (PCE) of 2.27%, JSC of 5.95 mAcm?2, VOC of 0.54 V and FF of 71%. The enhanced performance of this dye could be related to the powerful electron-withdrawing characteristic of the 4-aminobenzoic acid as an acceptor group in the dye structure. Consequently, the impact of various acceptor groups on the constructed DSSC devices was examined, and the results indicated that the improvement of DSSC performance is due to the presence of 4-aminobenzoic acid as acceptor on the carbazole-based dyes.
关键词： 4-aminobenzoic acid,Malonic acid,Dye-sensitized solar cell (DSSC),Carbazole,Cyanoacetic acid
更新于2025-09-23 15:21:01
-
Theoretical and Conceptual Framework to Design Efficient Dye-Sensitized Solar Cells (DSSCs): Molecular Engineering by DFT Method
摘要： Herein, eight new donor-p-acceptor organic dyes namely M1–M8 have been theoretically investigated for their potential in optoelectronic properties. The M1–M8 were designed through structural modi?cation of p-conjugated bridge of reference reported molecule IC2. The designed molecules contain Indolo[3,2,1-jk]carbazole as core donor unit and end capped cyanoacrylic acid as acceptor unit. DFT and TDDFT calculations using B3LYP, CAM-B3LYP, xB97XD and M062X functional were performed to evaluate the photophysical and photovoltaic properties. Results indicate that HOMO–LUMO energy gaps in M1–M8 have been found smaller than IC2. Among all, M7 is a material with lowest energy gap 2.61 eV, red shifted absorption wavelength value 436 nm. Results of the calculated redox potential of the ground state, vertical excitation energy of the dye, oxidation potential of the dye in the excited state, free energy change for electron injection, dye regeneration and open circuit photovoltage and light harvesting ef?ciency indicates that p-bridges in M1–M8 would show better power conversion ef?ciency than IC2. Especially, dye M7 with p-bridge 5-(thiazol-5yl)thiazole is found to be the most promising candidate for highly effective DSSCs properties. This theoretical framework may provide new ways for experimentalists to design high-performance DSSCs materials for optoelectronic applications.
关键词： Molecular modeling,p-conjugated linkers,Indolo[3,2,1-jk]carbazole,DSSCs
更新于2025-09-23 15:21:01
-
Carbazole/Benzimidazole-Based Bipolar Molecules as the Hosts for Phosphorescent and Thermally Activated Delayed Fluorescence Emitters for Efficient OLEDs
摘要： A series of carbazole/benzimidazole-based molecules, namely, o-CbzBiz, m-CbzBiz, and p-CbzBiz, were readily synthesized in three steps by integrating carbazole with benzimidazole via the ortho-, meta-, and para-positions of phenyl linked to N-phenyl carbazole. These bipolar molecules exhibited a maximum UV absorption band ranging from 310 to 327 nm and a maximum emission band ranging from 380 to 400 nm. Density functional theory calculations showed that the twist angles between the donor and acceptor moieties of these molecules were from 54.9 to 67.1°. Such a twisted structure hampered the π-electron conjugation within the molecule and resulted in high-lying LUMO levels and triplet energies, which make them suitable to be applied as host materials in OLED devices. Our results showed that a maximum external quantum efficiency (EQE) of OLED reached 21.8% when p-CbzBiz was applied as the host of a green phosphorescent emitter, i.e., Ir(ppy)2(acac). In addition, a maximum EQE of OLED reached 16.7% when o-CbzBiz with the host of a green TADF emitter, i.e., 4CzIPN. Moreover, these devices exhibited lower efficiency roll-off than the CBP-hosted device using the same emitters, which demonstrated the bipolar charge carrier property of carbazole/benzimidazole-based molecules.
关键词： thermally activated delayed fluorescence,bipolar molecules,phosphorescent,carbazole,OLEDs,benzimidazole
更新于2025-09-23 15:21:01
-
Realization of deep-blue TADF in sterically controlled naphthyridines for vacuum- and solution-processed OLEDs
摘要： Narrow-band deep-blue (emission peak < 460 nm) TADF emitters are in demand for commercial OLED display applications, yet the development of efficient emitters with low efficiency roll-off is very challenging. To address this issue herein we studied carbazole-naphthyridine (donor-acceptor) based blue-emitting TADF compounds, which were designed by considering both H-bonding and sterically controlled charge-transfer (CT) interactions between D and A units. Methyl substitution employed at the 1st position of t-butyl-carbazole donors was found to affect CT strength and consequently TADF properties of the studied compounds enabling significant reduction of delayed fluorescence lifetime (down to 3.1 μs) and enhancement of reverse intersystem crossing rate (up to 106 s-1). The naphthyridines were demonstrated to hold great potential for deep-blue TADF emitters suitable for both vacuum- and solution-processed TADF OLEDs. The optimized devices with 7 wt% of naphthyridine emitter in weakly polar mCP host delivered external quantum efficiencies (EQEs) of up to ~17.6% and ~13.5% for vacuum- and solution-processed OLEDs, respectively. Unsubstituted naphthyridine exhibited deep-blue (λmax < 460 nm) and narrow-band (FWHM = 66 nm) electroluminescence, whereas more twisted methyl-substituted compound expressed broader band (FWHM >80 nm) sky-blue (λmax ? 480 nm) emission. The demonstrated emitters are among the best-performing conventional D-A-type blue/deep-blue TADF emitters in terms of EQE and efficiency roll-off properties of their devices.
关键词： H-bonding,carbazole,deep-blue,charge-transfer,OLED,TADF,naphthyridine
更新于2025-09-23 15:21:01