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An eco-friendly imprinted polymer based on graphene quantum dots for fluorescent detection of <i>p</i> -nitroaniline
摘要： An eco-friendly fluorescent molecularly imprinted polymer anchored on the surface of graphene quantum dots (GQDs@MIP) was developed with an efficient sol–gel polymerization for highly sensitive and selective determination of p-nitroaniline (p-NA). The GQDs@MIP was characterized in detail by Fourier-transform infrared, fluorescence spectrometer, scanning electron microscope, transmission electron microscope and ultraviolet spectrophotometer. The results showed that the imprinted layer was successfully grafted on the surface of the GQDs. The fluorescence of the GQDs@MIP is efficiently quenched when p-NA recombines with the imprinting sites based on the photo-induced electron transfer fluorescence quenching mechanism. A good linear relationship was obtained between the fluorescence quenching efficiency of the GQDs@MIP and the concentration of p-NA in the range of 0–15.0 mM with a correlation coefficient of 0.99. The practicability of the proposed method in real samples was successfully evaluated through monitoring p-NA in water and fish samples with satisfactory recovery. The developed method provides a feasible and eco-friendly strategy to fabricate MIPs anchored on GQDs with good fluorescence properties for sensitive detection of organic pollutants in complex samples.
关键词： graphene quantum dots,fluorescent molecularly imprinted polymer,p-nitroaniline,fluorescence quenching,eco-friendly
更新于2025-09-16 10:30:52
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A novel optical fiber glucose biosensor based on carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film
摘要： A novel optical fiber glucose biosensor based on fluorescent carbon quantum dots (CQDs)-glucose oxidase (GOD)/cellulose acetate (CA) complex sensitive film was fabricated, in which the dip-coating method was adopted to immobilize the CQDs-GOD/CA complex sensitive film onto the end face of the optical fiber. The surface morphology, microstructure and optical performances of the sensitive film were characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Zeiss Axiovert 25 inverted microscope, Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectrophotometer and fluorescence spectrophotometer, respectively. The developed fiber-optic biosensor exhibits high sensitivity and repeatability for continuous online detection of low concentration glucose, allowing visualization of real-time glucose fluctuations over a period of time. The change ratios in fluorescence intensity of the biosensor are linear with glucose concentration in various ranges including micromole and nanomole levels, and the relationship between relative fluorescence intensity ratio and glucose concentration complies well with the modified Stern-Volmer equation in the range of 10-200 μmol/L with the detection limit of 6.43 μM, and in the range of 10-100 nmol/L with the detection limit of 25.79 nM, respectively.
关键词： Optical fiber,Carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film,Glucose sensing,Fluorescence quenching
更新于2025-09-16 10:30:52
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Trichromophore-doped cassava-based biopolymer as low-cost and eco-friendly luminous material for bio hybrid white-light-emitting diodes by dual-FRET process
摘要： White-light-emitting diodes (WLEDs) are promoted as environmentally friendly because they are energy saving-features and mercury-free aspects, but, rare-earth-free, metal-free, cost-competitive, and eco-friendly for brighter WLEDs are attractive but quite challenging in practice. This paper reports a new methodology using biopolymer luminous material in bio hybrid white-light-emitting diodes (Bio-HWLEDs) based on a trichromophore-doped cassava crystalline thick film that emits bright white light emission through a dual F?rster resonance energy transfer (FRET) process. The dual-FRET takes place from coumarin to sulforhodamine via the curcumin chromophore. The Bio-HWLED showed color co-ordinates (0.33, 0.32) that exactly matched with pure white light emission. The effect of temperature on luminescence and the activation energy for thermal quenching were determined using the temperature-dependent photoluminescence measurements. Moreover, Bio-HWLED showed a low luminous drop rate of 0.00069 s?1 to overcome the aggregation-induced quenching effect. These results pave the way towards the realization of commercially viable, large-scale and high-contrast bio hybrid light applications that are environmentally friendly.
关键词： Chromophore,Cassava,Bio-LEDs,Dual-FRET,Quenching effect
更新于2025-09-16 10:30:52
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Extremely robust gas quenching deposition of halide perovskites on top of hydrophobic hole transport materials for inverted (p-i-n) solar cells by targeting the precursor wetting issue.
摘要： Lead halide perovskite solar cells afford high power conversion efficiencies, even though the photoactive layer is formed in a solution process. At the same time, solution processing may impose some severe de-wetting issues, especially if organic, hydrophobic charge transport layers are considered. Ultimately, very narrow processing windows with a relatively large spread in device performance and a considerable lab-to-lab variation result. Here, we unambiguously identify dimethylsulfoxide (DMSO), which is commonly used as a co-solvent and complexing agent, to be the main reason for de-wetting of the precursor solution on hydrophobic hole transport layers, such as polytriarylamine (PTAA), in a gas quenching assisted deposition process. In striking contrast, we will show that n-methyl-2-pyrrolidon (NMP), which has a lower hydrophilic-lipophilic-balance, can be favorably used instead of DMSO to strongly mitigate these de-wetting issues. The resulting high-quality perovskite layers are extremely tolerant with respect to the mixing ratio (NMP:DMF) and other process parameters. Thus, our findings afford an outstandingly robust, easy to use and failsafe deposition technique yielding single (MAPbI3) and double (FA0.94Cs0.06PbI3) cation perovskite solar cells with high efficiencies (~ 18.5 %). Most notably, the statistical variation of the devices is significantly reduced, even if the deposition process is performed by different persons. We foresee, that our results will further the reliable preparation of perovskite thin films and mitigate process-to-process variations that still hinder the prospects of upscaling perovskite solar technology.
关键词： gas quenching,perovskite solar cells,reproducibility,perovskite precursor wetting,perovskite deposition
更新于2025-09-16 10:30:52
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Characterization of Latent 3D Laser Photoexposure Patterns in Photoresist Created by Direct Laser Writing
摘要： We describe photoluminescence quenching method for use in characterizing 3D laser photoexposure patterns in photoresist recorded during direct laser writing prior to development. By scanning a focused laser beam through the exposed patterns in the photoresist, important features of the photoexposure patterns, such as their size and shape, and the exposure threshold can be determined.
关键词： quenching,threshold,direct laser writing (DLW),photoexposure,photoluminescence (PL)
更新于2025-09-16 10:30:52
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A highly sensitive and selective detection of picric acid using fluorescent sulfura??doped graphene quantum dots
摘要： The development of an analytical probe to monitor highly mutagenic picric acid (PA) carries enormous significance for the environment and for health. A novel, simple and rapid fluorescence analytical assay using sulfur-doped graphene quantum dots (SGQDs) was designed for the highly sensitive and selective detection of PA. SGQDs were synthesized via simple pyrolysis of 3-mercaptopropionic acid and citric acid and characterized using advanced analytical techniques. Fluorescence intensity (FI) of SGQDs was markedly quenched by addition of PA, attributed to the inner filter effect and dominating static quenching mechanism between the two, in addition to a significant colour change. The calibration curve of the proposed assay exhibited a favourable linearity between quenched FI and PA concentration over the 0.1–100 μΜ range with a lowest detection limit of 0.093 μΜ and a correlation coefficient of 0.9967. The analytical assay was investigated for detection of trace amounts of PA in pond and rain water samples and showed great potential for practical applications with both acceptable recovery (98.0–100.8%) and relative standard deviation (1.24–4.67%). Analytical performance of the assay in terms of its detection limit, linearity range, and recovery exhibited reasonable superiority over previously reported methods, thereby holding enormous promise as a simple, sensitive, and selective method for detection of PA.
关键词： static quenching,inner filter effect,picric acid,fluorescent probe,sulfur-doped graphene quantum dots
更新于2025-09-16 10:30:52
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Laser-induced fluorescence of helium ions in ITER divertor
摘要： Laser-induced fluorescence (LIF) on ITER will be used for local measurement of helium density nHe and ion temperature Ti in divertor. The LIF diagnostic is combined with the divertor Thomson scattering (DTS) via common laser injection and signal collection optics. Collisional-radiative model developed for helium ions is used to estimate laser parameters required for robust measurement of laser-induced signals against plasma background radiation. The estimations demonstrate feasibility of measuring nHeII with laser parameters provided by available optical parametric oscillator pumped by Nd:YAG. New approach for measuring Ti is proposed and the expected errors are estimated using numerical simulations.
关键词： Helium density,ITER,Laser-induced quenching,Laser-induced fluorescence,Ion temperature,Divertor
更新于2025-09-16 10:30:52
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Water-soluble ZnO quantum dots modified by (3-aminopropyl)triethoxysilane: The promising fluorescent probe for the selective detection of Cu2+ ion in drinking water
摘要： Copper, as an essential element in human body, can have adverse impact on environment and healthy individuals if it is excessive. So it is necessary to establish a rapid and effective method for detecting Cu2+. In this work, we describe a method for determination of Cu2+ based on water-soluble ZnO quantum dots (QDs) modified with (3-aminopropyl)triethoxysilane (APTEs). The ZnO QDs functionalized with APTEs (NH2-ZnO QDs) synthesized by a simple sol-gel method and displayed strong yellow-green fluorescence with a peak at 535 nm under 350 nm excitation. High-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, luminescence, and UV-visible absorption spectroscopy were used to characterize the NH2-ZnO QDs. In addition, the emission from NH2-ZnO QDs was selectively quenched upon addition of Cu2+. Therefore, this finding was used to design a fluorescent probe based on NH2-ZnO QDs to detect Cu2+ in water solution, and the linear relationships were 2-20 nM and 1-100 μM respectively, with detection limit for Cu2+ at 1.72 nM (on the basis of 3σ/slope criterion). This fluorescent probe had also been applied in real water sample to testify its availability in drinking water. Furthermore, the quenching mechanism was studied by measurements of UV-visible absorption spectra and fluorescent lifetime of ZnO QDs, which may be attributed to the aggregation induced by Cu2+ and the dynamic quenching existing energy transfer between QDs and Cu2+.
关键词： Drinking water,Water-soluble,Fluorescent probe,Cu2+ detection,ZnO QDs,Quenching mechanism
更新于2025-09-16 10:30:52
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Efficiency enhancement of small molecule organic solar cells using hexapropyltruxene as an interface layer
摘要： The quenching of excitons in organic solar cells can play a significant role in limiting their power conversion efficiency (PCE). In this article, we investigate the effect of a thin layer of hexapropyltruxene inserted at the interface between the electron donor boron subphthalocyanine chloride (SubPc) and its underlying hole contact in planar heterojunction solar cells. We find that a 3.8 nm hexapropyltruxene interlayer between the molybdenum oxide (MoOx) hole contact and SubPc is sufficient to improve PCE in SubPc/C60 fullerene solar cells from 2.6 % to 3.0 %, a ～20 % performance improvement. While the absorption stays roughly the same, the comparison of external and internal quantum efficiencies reveals a significant increase in SubPc’s contribution to the current for light with wavelengths between 520 and 600 nm. Microstructure and surface morphology assessed with in-situ Grazing-Incidence Wide-Angle X-Ray Scattering (GIWAXS) and Atomic Force Microscopy (AFM), are evaluated alongside in-situ spectroscopic ellipsometry, and photoluminescence measurements. The microstructural investigations demonstrate changes to the surface and bulk of SubPc grown atop a hexapropyltruxene interlayer indicating that the latter acts as a template layer in a similar way as MoOx. However, the improvement in PCE is found to be mainly via reduced exciton quenching at the MoOx contact with the insertion of the hexapropyltruxene layer.
关键词： hexapropyltruxene,power conversion efficiency,exciton quenching,organic solar cells,SubPc/C60
更新于2025-09-16 10:30:52
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Performance Enhancement of All-Inorganic Quantum Dot Light-Emitting Diodes via Surface Modification of Nickel Oxide Nanoparticles Hole Transport Layer
摘要： All-inorganic quantum dot light-emitting diodes (QLEDs) show promise for advanced lighting and display due to their superior advantage in stability. However, all-inorganic QLEDs suffer from the low efficiency because of the exciton quenching and inefficient hole transport from inorganic hole transport layer (HTL) to QDs. Herein, we demonstrate an efficient all-inorganic QLED with NiO nanoparticals (NPs) HTL modified by 11-mercaptoundecanoic acid (MUA). The MUA can passivate the defects of NiO and suppress the exciton quenching. Moreover, the declined valance band level of modified NiO could facilitate the hole transport, promoting the charge balance. In addition, the surface engineering improves the quality of NiO film, leading to the decrease of current leakage. As a result, the maximum current efficiency and external quantum efficiency (EQE) of our QLEDs achieve 5.50 cd/A and 1.28%, respectively, exhibiting the enhancement of 4.5 and 1.72 folds, respectively. Meanwhile, the stability of the device is drastically improved by more than 20 folds after modifying the NiO with MUA. The strategy offers a pathway to enhance the efficiency and the operation lifetime of all-inorganic QLEDs.
关键词： exciton quenching,nickel oxide nanoparticles,performance enhancement,surface modification,all-inorganic quantum dot light-emitting diodes
更新于2025-09-16 10:30:52