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Structure and Conformation of a Crystalline P3HT Film Adsorbed on an Alkanethiol Self-Assembled Monolayer Deposited on Gold
摘要： All-atom molecular dynamics simulations are performed to investigate the structural and conformational properties of a regioregular poly(3-hexylthiophene) (P3HT) crystal in the presence of a gold (Au) substrate terminated with an n-alkanethiol self-assembled monolayer (SAM). The employed orientation of the P3HT crystals deposited on the SAM is the edge-on, since this orientation is believed to be the most energetically favorable and stable, also yielding the highest charge carrier mobility in organic thin-film transistors. The unit cell of the overall Au/SAM interfacial layer is obtained through detailed ab initio calculations. Systems with a varying number of P3HT stacks on the Au/SAM substrate are studied with an all-atom force field in order to elucidate the effect of polymer thickness on the structural properties of the system. All final structures are found to be stable and well-equilibrated. Insights into the P3HT crystal structure are provided for the P3HT layers in direct contact with the SAM, but also for those deeper in the polymer film. According to the simulations, the majority of conformational and packing properties of the P3HT film are practically similar to those of the bulk crystalline P3HT material, implying that its structure remains unaffected by the presence of the underlying Au/SAM substrate.
关键词： DFT calculations,semiconducting polymers,molecular dynamics simulations,self-assembled monolayers,P3HT
更新于2025-09-23 15:19:57
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Insulating Polymers for Enhancing the Efficiency of Nonfullerene Organic Solar Cells
摘要： A series of insulating polymers are used as additives in nonfullerene organic solar cells (OSCs) for the first time. A significant relative power conversion efficiency (PCE) enhancement of up to 16% is observed with an introduction of polystyrene for only 5.0 wt% into the active layer of OSCs. Other insulating polymers possessing linear nonconjugated backbones with different side chains are also incorporated into OSCs and the resultant PCE enhancement decreases with the decrease in the side chain size. Another important issue that is noted is the glass transition temperature of the polymer additive. When the glass transition temperature is higher than the thermal annealing temperature of the active layer, the polymer additive plays a negative effect on the device performance and the device efficiency decreases monotonically with the increase in addition amount. So the effect of the insulating polymer additives in nonfullerene OSCs can be attributed to the reconstruction of the active layer films, which increases the crystallinity, carrier mobility, and carrier lifetime of the organic semiconductors in the bulk heterojunction of the devices. This work provides a guideline for the selection of polymer additives in OSCs apart from the consideration on the optoelectronic property of the additives.
关键词： nonfullerenes,insulating polymers,organic solar cells,additives,glass transition temperatures
更新于2025-09-23 15:19:57
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Preparation of molecularly imprinted fluorescence sensor based on carbon quantum dots via precipitation polymerization for fluorescence detection of tetracycline
摘要： A facile and effective method was proposed to prepare the molecularly imprinted fluorescence sensor with carbon quantum dots, which were modified vinyl groups by acrylic acid on the surface. The obtained fluorescence composite material was investigated by transmission electron microscope and Fourier transform infrared spectra. After the experimental conditions were optimized, a linear range of 1.0–60 μmol L?1 was obtained and the detection limit was 0.17 μmol L?1. The novel fluorescence sensor can be successfully used to detect tetracycline in real samples. This study provides a convenient strategy for selective recognition and rapid detection of tetracycline in the complex environment.
关键词： precipitation polymerization,tetracycline,carbon quantum dots,molecularly imprinted polymers,fluorescence detection
更新于2025-09-23 15:19:57
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Xanthene Dye-Functionalized Conjugated Porous Polymers as Robust and Reusable Photocatalysts for Controlled Radical Polymerization
摘要： Photoinduced electron/energy transfer?reversible addition?fragmentation chain transfer (PET?RAFT) polymerization represents a versatile and highly e?cient method for polymerizations of wide-ranging monomer variances upon solar energy harvesting. Although signi?cant progress has been achieved, several drawbacks are still associated with existing photocatalysts, such as toxicity of transition metals, high cost, poor stability, and unavoidable puri?cation procedures because of the photobleaching e?ect, to name a few. Herein, 1,4-diethynylbenzene-linked xanthene dye-conjugated porous polymers (CPPs) have been established as potential heterogenous photocatalysts of PET?RAFT polymerization. With this two-dimensional planar architecture, we demonstrate dual-stimuli toggling of RAFT polymerization using two di?erent external physical manipulations: light “ON”/“OFF” and solution pH “LOW”/“HIGH”. In addition, these CPPs endowed radical polymerizations with various impressive features such as compatibility of diverse monomer formulations, unique oxygen tolerance, and ppm-level catalyst dosage. Demonstrations of chain extension and catalyst recycling further highlight the robustness and performance of this CPP catalyst. Through the study of structure?property relationship using the experimental analyses, we envisage that a series of xanthene dye-functionalized CPPs can be developed as visible light-absorbing organocatalysts rivaling transition-metal photocatalysts.
关键词： PET?RAFT polymerization,visible light-absorbing organocatalysts,xanthene dye-functionalized conjugated porous polymers,dual-stimuli toggling,heterogeneous photocatalysts
更新于2025-09-23 15:19:57
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Single-material organic solar cells with fully conjugated electron-donor alkoxy-substituted bithiophene units and electron-acceptor benzothiadiazole moieties alternating in the main chain
摘要： Main chain conjugated linear polymers, constituted by alternating electron-donor (D) and -acceptor (A) moieties, have been prepared with the aim of testing their performances as photoactive components in single material organic solar cells (SMOSCs). The D moiety is constituted by bithiophene co-units bearing in the position 3 of the thiophene ring an hexyloxy, a hexyloxymethyl or a hexyl group, while the A moiety is represented by the benzothiadiazole group. The D–A polymers were obtained in high yield through the poorly demanding oxidative FeCl3 polymerization process - starting, respectively, from the related precursors 4,7-bis(3-hexyloxythiophen-2-yl)benzo[c][2,1,3]thiadiazole, 4,7-bis[3-(6-methoxyhexyl)thiophen-2-yl]benzo[c][2,1,3]thiadiazole and 4,7-bis(3-hexylthiophen-2-yl)benzo[c][2,1,3]thiadiazole - with low dispersity indexes, close to the monodisperse state, after fractionation with methanol. The materials have been thoroughly characterized for their physical and structural properties and then tested for photoconversion efficiency in SMOSCs by using different deposition procedures of the photoactive component. In agreement with Kelvin probe force microscopy (KPFM) measurements, the best photovoltaic performance was observed for the polymer based on conjugated 3-alkoxythiophene and benzothiadiazole moieties, achieving significant photocurrents for this type of fully conjugated alternating D–A structures (Jsc = 2.63-3.72 mA cm-2).
关键词： alternating D–A polymers,alkoxy alkyl substituents,photo-charges,Single-material organic solar cells,spray coating method
更新于2025-09-23 15:19:57
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Sensing of Furfural by Molecularly Imprinted Polymers on Plasmonic and Electrochemical Platforms
摘要： The goal of this work is to test the possibility of selective detection of furfural (2-FAL) in aqueous solutions, with a molecularly imprinted polymer (MIP) receptor exploiting two different transduction methods, for food safety applications. In particular, sensors with electrochemical and surface plasmon resonance (SPR) transduction are considered. Two concentration ranges could be investigated by the different sensing approaches since the detectable concentration level depends on the sensitivity of the detection technique employed. The determination of 2-FAL at different concentration levels in the aqueous medium of interest, as for example beverages, is becoming a very crucial task not only for the relevance of furanic compounds in affecting the flavor but also for their possible toxic and carcinogenic effects on the human beings. For these reasons, their determination by a fast, easy and low-cost method is of interest. The sensor methods here proposed appears to be particularly suitable, since, although together and not individually, they allow the determination in a wide concentration range.
关键词： furfural (2-FAL),electrochemical sensors,molecularly imprinted polymers (MIPs),optical-chemical sensors,plastic optical fibers (POFs),surface plasmon resonance (SPR)
更新于2025-09-23 15:19:57
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Synthesis, electrochromic characterization and solar cell application of thiophene bearing alternating copolymers with azobenzene and coumarin subunits
摘要： In this study, azobenzene and coumarin functionalized thiophene comprising two copolymers (poly (4-((3000-hexyl-[2,20:50,200:500,2000-tetrathiophene] (cid:2) 30-yl)methoxy) - 2H-chromen-2-one (P1) and poly (1-(4-((4000-hexyl-[2,20: 50, 200: 500, 2000 - tetrathiophene] (cid:2) 30-yl) methoxy) phenyl) (cid:2)2-phenyldiazene) (P2)), were designed and synthesized according to the donor–acceptor (D–A) approach to investigate their electrochemical, optical and photovoltaic behaviors. Among the various copolymerization methods to obtain P1 and P2, Stille copolymerization reaction was preferred. The HOMO and LUMO values were determined via cyclic voltammetry (CV) as (cid:2)5.64 eV and (cid:2)3.76 eV for P1 and (cid:2)5.47 eV and (cid:2)3.83 eV for P2, respectively. The optical band gaps of the polymers for P1 and P2 were calculated as 1.88 eV and 1.64 eV using UV-VIS spectrophotometer. Electrochemical and spectroelectrochemical studies for synthesized copolymers support their usage in organic solar cell applications. The organic solar cells (OSCs) were designed using polymer as an electron donor group and PC60BM as an electron acceptor group. Performances of OSCs based on P1 and P2 were investigated with the device structure of ITO/PEDOT:PSS/ Polymer(P1/P2):PC60BM/LiF/Al. The preliminary solar cell results were reported here and studies are going on in our laboratories to increase the efficiency. The highest power conversion efficiency was obtained as 0.81% for P1 based device with 0.47 V open-circuit voltage (Voc) and 4.92 mA/cm2 current density (Jsc) values. The highest efficiency for P2 comprising device was found to be 0.96% under optimum conditions with 0.60 V and 4.98 mA/cm2, Voc and Jsc values, respectively.
关键词： Azobenzene,solar cell,coumarin,conducting polymers,thiophene bearing copolymers
更新于2025-09-23 15:19:57
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Perdeuterated conjugated polymers for ultralowa??frequency magnetic resonance of OLEDs
摘要： The formation of excitons in OLEDs is spin dependent and can be controlled by electron-paramagnetic resonance, affecting device resistance and electroluminescence yield. We explore electrically detected magnetic resonance in the regime of very low magnetic fields (< 1 mT). A pronounced feature emerges at zero field in addition to the conventional spin-1=2 Zeeman resonance for which the Larmor frequency matches that of the incident radiation. By comparing a conventional p-conjugated polymer as the active material to a perdeuterated analogue, we demonstrate the interplay between the zero-field feature and local hyperfine fields. The zero-field peak results from a quasistatic magnetic-field effect of the RF radiation for periods comparable to the carrier-pair lifetime. Zeeman resonances are resolved down to 3.2 MHz, approximately twice the Larmor frequency of an electron in Earth(cid:3)s field. However, since reducing hyperfine fields sharpens the Zeeman peak at the cost of an increased zero-field peak, we suggest that this result may constitute a fundamental low-field limit of magnetic resonance in carrier-pair-based systems. OLEDs offer an alternative solid-state platform to investigate the radical-pair mechanism of magnetic-field effects in photochemical reactions, allowing models of biological magnetoreception to be tested by measuring spin decoherence directly in the time domain by pulsed experiments.
关键词： conjugated polymers,deuteration,magnetic resonance,isotopes,organic light-emitting diodes
更新于2025-09-23 15:19:57
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Determining the sequence and backbone structure of a??semi-statisticala?? copolymers as donora??acceptor polymers in organic solar cells
摘要： Organic photovoltaics (OPVs) are attracting significant attention due to the growing demand for economically viable and renewable energy sources. With efficiencies exceeding 16.5%, single junction bulk heterojunction (BHJ) devices are amongst the most promising and are nearing commercialisation. One recent avenue of research has focused on statistical conjugated copolymers. However, a detailed investigation as to why these materials can achieve higher power conversion efficiencies than their regular alternating counterparts is seldom reported. This work describes an investigation into donor–acceptor polymers demonstrating how differing monomer activities can lead to differing microstructures in a simple batch reaction, which in turn demonstrates promising optoelectronic and morphological properties required for organic photovoltaic devices. A one pot condensation polymerisation reaction with three monomers leads to an ABA triblock structure from differing monomer reactivities. This structure in turn leads to visualised phase separation which is possibly linked to an increase in performance. Further to this we report on the reliability of the Stille coupling for the synthesis of conjugated polymers.
关键词： Organic photovoltaics,Donor–acceptor polymers,Bulk heterojunction devices,Statistical conjugated copolymers,Stille coupling
更新于2025-09-23 15:19:57
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Solvent-controlled assembly of two Zn(II) coordination polymers constructed from 1,3,5-tris(1-imidazolyl)benzene and 2,5-dichloroterephthalic acid with fluorescent recognition of carcinogenic dye in chloroform
摘要： Two Zn(II) coordination polymers, [Zn2(tib)2(BDC-Cl2)(HBDC-Cl2)2](cid:1)2H2O (1) and [Zn(tib)(BDC-Cl2)](cid:1)H2O (2), were synthesized by reaction of 1,3,5-tris(1-imidazolyl)benzene (tib) and 2,5-dichloroterephthalic acid (H2BDC-Cl2) with Zn2t under solvothermal conditions. The results of X-ray single-crystal analysis show that 1 possesses a 1-D chain structure, while 2 exhibits a 2-D layer structure with {44(cid:1)62} topology. Both display a 3-D supramolecular framework through hydrogen bonding interactions. Experimental results indicated that the ratio of solvent may regulate the structural formation of the polymers. 1 and 2 were further characterized by powder X-ray diffraction (PXRD), IR spectroscopy, thermogravimetric analysis (TGA), and elemental analysis. Notably, 1 and 2 possess the ability to identify chloroform by emitting specific fluorescence spectra. Both can detect carcinogens in dyes by the modified fluorescent signal of the compound in chloroform.
关键词： crystal structure analysis,mixed-ligand strategy,carcinogen identification,Zinc(II)-coordination polymers,fluorescent recognition
更新于2025-09-23 15:19:57