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A high-performance room temperature methanol gas sensor based on alpha-iron oxide/polyaniline/PbS quantum dots nanofilm
摘要： A high-performance room temperature methanol gas sensor based on alpha-iron oxide/polyaniline/lead sulfide quantum dots (α-Fe2O3/PANI/PbS QDs) nanofilm was demonstrated in this paper, among which the α-Fe2O3 was an urchin-shaped hollow microsphere. The sensing film was fabricated on an epoxy substrate with interdigital electrodes via successive ionic layer adsorption and reaction technique. The prepared α-Fe2O3/PANI/PbS QDs nanocomposite was examined by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, scanning election microscopy and Fourier transform infrared spectrum. The methanol sensing performances of the α-Fe2O3/PANI/PbS QDs film sensor were investigated against methanol from 10 to 100 ppm at room temperature. The experimental results indicated that the methanol sensor in this work had an excellent response, outstanding selectivity and good repeatability at room temperature. The underlying sensing mechanism of the α-Fe2O3/PANI/PbS QDs film toward methanol was ascribed to a series of interactions and changes on the surface of thin films, which make their resistance change greatly. Larger surface area and much more active adsorption sites also played an important role.
关键词： Methanol gas sensor,Room temperature,Successive ionic layer adsorption and reaction,Hydrothermal method,α-Fe2O3/PANI/PbS QDs
更新于2025-11-14 17:15:25
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Phosphorimetric determination of 4-nitrophenol using mesoporous molecular imprinting polymers containing manganese(II)-doped ZnS quantum dots
摘要： Mesoporous molecularly imprinted polymers (MIPs) containing mangnanese-doped ZnS quantum dots (Mn-ZnS QDs) were prepared for specific recognition and detection of 4-nitrophenol (4-NP). The Mn-ZnS QDs display orange room-temperature phosphorescence with excitation/emission peaks at 295/590 nm and a decay time of 2.0 ms. In the presence of 4-NP, the orange phosphorescence is strongly reduced. Phosphorescence drops linearly in the 0.1–100 μM 4-NP concentration range, and the detection limit is 60 nM. The detection limit is far lower than the maximally allowed 4-NP concentrations in surface water and drinking water as specified by the U.S. Environmental Protection Agency. The intraday (n = 5) and interday (n = 6) spiked recovery rates were 96.0–104.5% and 97.9–107.9%, respectively, with relative standard deviations of 0.7–4.8% and 1.8–7.5% respectively. These MIPs integrated the characteristic features of phosphorimetry and molecular imprinting. Potential interference by competitive substances, background fluorescence or scattered light are widely reduced.
关键词： Room-temperature phosphorescence,Mesoporous molecularly imprinted polymers,Photoinduced electron-transfer,4-Nitrophenol,Decay time
更新于2025-11-14 17:04:02
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Carbon dots synthesized at room temperature for detection of tetracycline hydrochloride
摘要： The traditional synthesis methods of carbon dots (CDs) have some disadvantages of complicated operation and a large amount of energy consumption. To address these limitations, we synthesized yellow-green luminescent CDs at room temperature according to the principle of amine-aldehyde condensation in this work. This reaction is simple, economical, energy saving and is extremely consistent with the concept of green synthesis and sustainable development. In addition, studies have found that tetracycline hydrochloride (TC) can quench the fluorescence of the as-prepared CDs through Inner filter effect (IFE). The changes of the fluorescence intensity also have a good linear relationship with the concentration of TC in the range of 10.0-400.0 μM, and the detection limit is 6.0 μM. This method has been successfully used to determine the tetracycline content of tetracycline tablets. Finally, the interaction mechanism between TC and CDs was analyzed and discussed.
关键词： room temperature synthesis,tetracycline,carbon dots
更新于2025-11-14 17:03:37
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Insights into the improved photocatalytic performance of fluorine surface modified mpg-C3N4 at room temperature under aqueous conditions
摘要： A novel fluorine surface modified mesoporous carbon nitride (mpg-C3N4) photocatalysts were synthesized by etching SiO2 with NH4HF2. The mechanism of formation and the factors that affect its photocatalytic activity were investigated. Interestingly, the introduction of F atoms improves the performance of surface state and widens the energy band gap of surface-modified mpg-C3N4 due to the higher separation and efficient mobility of the photoinduced carriers. Consequently, the fluorine-modified mpg-C3N4 exhibits higher carrier lifetime (8.64 ns) than mpg-C3N4 (7.14 ns), which improves the photocatalytic efficiency under ultraviolet light. The enhanced photocatalytic activity was evaluated by studying the degradation experiments of Rhodamine B. It is expected that the present fluorine modification at the surface of mpg-C3N4 may provide new insights in basic research and energy conversion.
关键词： fluorine surface modification,mpg-C3N4,room temperature,photocatalyst
更新于2025-11-14 15:28:36
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{Zn <sub/>6</sub> } Cluster Based Metal–Organic Framework with Enhanced Room-Temperature Phosphorescence and Optoelectronic Performances
摘要： Molecule-based solid-state materials with long lifetimes could enable longer migration distances for excitons, which are beneficial for vast applications in optoelectronic field. Herein, we report a hexanuclear zinc cluster based MOF exhibits highly enhanced phosphorescence about 2 orders of magnitude in comparison with the pristine phosphor ligand. The combination of both experimental and computational results suggest that the {Zn6} cluster is very important for adjusting molecular conformations, packing arrangement, and photophysical properties of the organic phosphor ligands within the MOF matrix. Optoelectronic measurements reveal that the MOF-modified electrode is catalytically active to hydrogen evolution under light irradiation in neutral solution. Thus, our study provide an effective way to achieve low-cost metal-based phosphorescence MOF, expanding its further optoelectronic applications.
关键词： optoelectronic performances,metal?organic framework,hexanuclear zinc cluster,room-temperature phosphorescence
更新于2025-11-14 15:23:50
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Preparation of DNA functional phosphorescent quantum dots and application in melamine detection in milk
摘要： Bio-functionalization of quantum dots (QDs) is of important value in practical applications. With single-stranded DNA (ssDNA) rich in thymine T and thioguanine G taken as the template, a new-type nanocomposite material (ssDNA-PQDs) synthesized from low-toxicity T-ssDNA functionalized Mn–ZnS and room-temperature phosphorescent (RTP) QDs (PQDs) was prepared in this paper by optimizing synthesis conditions, and these ssDNA-PQDs could emit orange RTP signals at 590 nm. As these ssDNA-PQDs are rich in T sequences and T sequences can bond with melamine through the hydrogen-bond interaction, ssDNA-PQDs experience aggregation, thus causing phosphorescent exciton energy transfer (PEET) between ssDNA-PQDs of di?erent particle sizes and their RTP quenching. Based on this principle, an RTP detection method for melamine was established. The linear range and detection limit of the detection method are 0.005–6 mM and 0.0016 mM respectively. As this method is based on the RTP nature of ssDNA-PQDs, it can avoid disturbance from background ?uorescence and scattered light of the biological ?uid, and it is very suitable for melamine detection in the biological ?uid milk.
关键词： DNA functionalized quantum dots,milk safety,melamine detection,room-temperature phosphorescent
更新于2025-11-14 15:23:50
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Extrinsic heavy metal atom effect on the solid state room temperature phosphorescence of cyclic triimidazole
摘要： Four coordination compounds [Zn3(CH3COO)6(H2O)2](TT)2, [Cd(H2O)6](ClO4)2(TT)2, [Cd(H2O)6](BF4)2(TT)2, [Zn(H2O)6](BF4)2(TT)2 (1-4) accommodating triimidazo[1,2-a:1',2'-c:1'',2''-e][1,3,5]triazine (TT) as a guest in their crystal lattice are isolated and fully photophysically and structurally characterized. Their emission properties are compared with those of afterglow TT and interpreted taking into account the heavy atom effect and crystal packing similarities and differences. In the case of 1, due to the closeness of the TT H-aggregates arrangement with that of the phosphor's pure phase, the observed intensification of the phosphorescent emission at the expense of the prompt one is attributed to the extrinsic heavy atom effect of Zn. In 2 and 3, the heavier Cd atom is responsible for a decrease in the lifetimes of the afterglow emission, despite the presence of tightly overlapped H-dimers in the crystal structure. Finally for 4, isostructural with 3, the Zn atom reveals in RTUP lifetime comparable with that of 1.
关键词： extrinsic heavy atom effect,H aggregates,time resolved photoluminescence,room temperature ultralong phosphorescence,single crystal XRD
更新于2025-09-23 15:23:52
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Polymorphic Pure Organic Luminogens with Through Space Conjugation and Persistent Room Temperature Phosphorescence
摘要： Pure organic luminogens with persistent room temperature phosphorescence (p-RTP) have attracted increasing attention owing to their fundamental significance and potential applications in security inks, bioimaging, and photodynamic therapy. Previous p-RTP luminogens are normally with through bond conjugation. In this work, we report a pure organic luminogen, AN-MA, the Diels-Alder cycloaddition adduct of anthracene (AN) and maleic anhydride (MA), which possesses isolated phenyls and anhydride moiety. AN-MA exhibits aggregation-enhanced emission (AEE) characteristics, with efficiency of ~2% and up to 8.5% in solution and crystals, respectively. Two polymorphs of AN-MA are readily obtained, which can generate UV emission from individual phenyl rings together with bright blue emission owing to the effective through space conjugation. Moreover, p-RTP with lifetime of up to ~1.6 s is obtained in crystals. These results not only disclose a new system with both fluorescence and RTP dual emission, but also suggest an alternative through space conjugation strategy towards pure organic p-RTP luminogens with tunable emissions.
关键词： anticounterfeiting,pure organic luminogens,persistent room temperature phosphorescence,through space conjugation,polymorphism
更新于2025-09-23 15:23:52
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Suppressed Triplet Exciton Diffusion Due to Small Orbital Overlap as a Key Design Factor for Ultralong-Lived Room-Temperature Phosphorescence in Molecular Crystals
摘要： Persistent room-temperature phosphorescence (RTP) under ambient conditions is attracting attention due to its strong potential for applications in bioimaging, sensing, or optical recording. Molecular packing leading to a rigid crystalline structure that minimizes nonradiative pathways from triplet state is often investigated for efficient RTP. However, for complex conjugated systems a key strategy to suppress the nonradiative deactivation is not found yet. Here, the origin of small rates of a nonradiative decay process from triplet states of conjugated molecular crystals showing RTP is reported. Optical microscopy analysis showed that, despite a favorable molecular stacking, an aromatic crystal with strong RTP is characterized by small diffusion length and small values of the diffusion coefficient of triplet excitons. Quantum chemical calculations reveal a large overlap between the lowest unoccupied molecular orbitals but very small overlap between the highest occupied molecular orbitals (HOMOs). Inefficient electron exchange caused by the small overlap of HOMOs prevents triplet excitons from diffusing over long distances and consequently from quenching at defect sites inside the crystal or at the crystal surface. These results will allow design of comprehensive molecular structures to obtain molecular solids with more efficient RTP.
关键词： suppressed nonradiative rate,persistent room-temperature phosphorescence,triplet exciton diffusion,molecular orbital overlap,fluorescence microscopy
更新于2025-09-23 15:23:52
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UV Illumination-Enhanced Molecular Ammonia Detection Based On a Ternary-Reduced Graphene Oxide–Titanium Dioxide–Au Composite Film at Room Temperature
摘要： In this work, we report on UV illumination enhanced room-temperature trace NH3 detection based on ternary composites of reduced graphene oxide nanosheets (rGO), titanium dioxide nanoparticles (TiO2) and Au nanoparticles as the sensing layer, which is firstly reported by far. The effect of UV state as well as componential combination and content on the sensing behavior disclosed that, rGO nanosheets served as not only a template to attach TiO2 and Au, but an effective electron collector and transporter; TiO2 nanoparticles acted as a dual UV and NH3 sensitive material; Au nanoparticles could increase the sorption sites and promote charge separation of photoinduced electron-hole pairs. The as-prepared rGO/TiO2/Au sensors were endowed with a sensing response of 8.9% toward 2 ppm NH3, a sensitivity of 1.43×10-2/ppm within the investigated range, nice selectivity, robust operation repeatability and stability, which was fairly competitive in comparison with previous work. Meanwhile, the experimental results provided clear evidence of inspiring UV-enhanced gas detection catering for the future demand of low power-consumption and high sensitivity.
关键词： Room temperature.,Gas sensor,Reduce graphene oxide,Ammonia,Au nanoparticle,Titanium dioxide,UV illumination
更新于2025-09-23 15:23:52