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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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{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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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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Controlling the fluorescence and room-temperature phosphorescence behaviour of carbon nanodots with inorganic crystalline nanocomposites
摘要： There is a significant drive to identify alternative materials that exhibit room temperature phosphorescence for technologies including bio-imaging, photodynamic therapy and organic light-emitting diodes. Ideally, these materials should be non-toxic and cheap, and it will be possible to control their photoluminescent properties. This was achieved here by embedding carbon nanodots within crystalline particles of alkaline earth carbonates, sulphates and oxalates. The resultant nanocomposites are luminescent and exhibit a bright, sub-second lifetime afterglow. Importantly, the excited state lifetimes, and steady-state and afterglow colours can all be systematically controlled by varying the cations and anions in the host inorganic phase, due to the influence of the cation size and material density on emissive and non-emissive electronic transitions. This simple strategy provides a flexible route for generating materials with specific, phosphorescent properties and is an exciting alternative to approaches relying on the synthesis of custom-made luminescent organic molecules.
关键词： room temperature phosphorescence,photoluminescence,heavy atom effect,carbon nanodots,nanocomposites
更新于2025-09-23 15:22:29
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Ultralong Lifetime Room Temperature Phosphorescence and Dual-band Waveguide Behavior of Phosphoramidic Acid Oligomers
摘要： In recent years, some natural or synthetic non-conjugated luminescence systems have attracted much attention. However, the phosphorescent properties of these materials are generally not very satisfactory due to the lack of special molecular design. In this work, the phosphoramidic acid is introduced into the oligomer matrix to construct a non-conjugated photoluminescence system with ultralong phosphorescence lifetime up to 376.5 to 776.9 ms and high phosphorescence quantum yield (4.6-10.5 %). At the same time, the new system also displays good thermo-processing properties, vitreous solid and optical waveguide behavior.
关键词： Room temperature phosphorescence,ultralong phosphorescence lifetime,phosphoramidic acid oligomers,optical waveguide behavior
更新于2025-09-23 15:21:01
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Circularly Polarized Rooma??Temperature Phosphorescence and Encapsulation Engineering for MOFa??Based Fluorescent/Phosphorescent WLEDs
摘要： Optical materials with circularly polarized luminescence and room temperature phosphorescence currently attract great attention owing to their unique optoelectronic properties. Herein, via the coordination-induced assembly strategy, a homochiral metal–organic framework (MOF) 1 with high stability and porosity is successfully synthesized by using the achiral triphenylamine-based molecule as the building block. Remarkably, MOF 1 shows circularly polarized luminescence and phosphorescence at room temperature simultaneously, also with excellent anisotropic optical properties. Furthermore, MOF 1 can serve as a nanocontainer to construct dye-encapsulated host–guest systems. Importantly, the multicolor emissions including white-light emission can be achieved. The corresponding color rendering index and correlated color temperature values of light emitting device are 73 and 5541 K, when using dye-loaded MOF 1?RhB 10 (CIE: 0.33, 0.33) as single-phase white light-emitting phosphor. This study first reports circularly polarized phosphorescence based on MOF without precious metals under ambient conditions, and also is first time for phosphorescent polarized materials with high porosity. These results will open up a new pathway to the design of porous chiroptical materials and white-light materials.
关键词： circularly polarized luminescence,host–guest system,room temperature phosphorescence,white light emitting devices,metal–organic frameworks
更新于2025-09-23 15:21:01
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Portable Instrument for Monitoring Environmental Toxins Using Immobilized Quantum Dots as the Sensing Material
摘要： A portable instrumental system was designed for the routine environmental monitoring of toxic volatile organic compounds (VOCs) in atmospheric conditions based on changes in the photoluminescence emission of semiconductor nanoparticles (quantum dots) entrapped in a sol-gel matrix as the solid sensing material. The sol-gel sensing material displayed a long-lived phosphorescent emission, which is quenched in the presence of trace levels of a volatile organic compound (acetone) in gaseous atmospheres. The developed instrument could measure and process the changes in the photoluminescence of the sensing material after exposure to gaseous acetone. The developed prototype device consists of a deep-ultraviolet light-emitting diode (UV LED), which excites the chemical sensing material; an optical filter to remove scattered light and other non-desirable wavelengths; a photomultiplier tube (PMT) to convert the phosphorescence emission of the sensor phase to an electrical signal; and a microcontroller to correlate the signal with the analyte concentration. The developed prototype was evaluated for its ability to measure low levels of gaseous acetone in contaminated atmospheres with high sensitivity (detection limit: 9 ppm). The obtained results show the feasibility of this type of instrument for environmental analytical control purposes.
关键词： quantum dots (QDs),photomultiplier,UV LED,instrumentation,nanoparticles,room temperature phosphorescence (RTP)
更新于2025-09-23 15:21:01
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Heavy Atom Effect of Selenium for Metal-Free Phosphorescent Light-Emitting Diodes
摘要： Room-temperature phosphorescence from metal-free purely organic molecules has recently gained much interest. We devised metal-free organic phosphors by incorporating selenium (Se) to promote spin?orbit coupling by its nonmetal heavy atom effect. The Se-based organic phosphors showed bright phosphorescent emission in organic light-emitting diodes (OLEDs) and photo-excited phosphorescence in an amorphous film state. Large orbital angular momentum change (ΔL) during the electron transition process and heavy atom effect of Se render a PL quantum yield of 0.33 ± 0.01 and a high external quantum efficiency (EQE) of 10.7 ± 0.14% in phosphorescent LEDs. This work demonstrates the rational molecular design of metal-free organic phosphorescent emitters with Se as an alternative novel class of materials to the conventional organometallic phosphors for OLEDs.
关键词： organic light-emitting diodes,spin?orbit coupling,selenium,metal-free organic phosphors,phosphorescent LEDs,room-temperature phosphorescence
更新于2025-09-23 15:19:57
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An iminodibenzyl–quinoxaline–iminodibenzyl scaffold as a mechanochromic and dual emitter: donor and bridge effects on optical properties
摘要： The influence of phenyl linkage and donor strength on the photophysical properties of new derivatives of quinoxaline-containing iminodibenzyl and iminostilbene moieties is studied. The donor–acceptor derivatives showed dual thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) despite a large energy gap between the excited singlet and triplet states (ca. 0.5 eV). This extremely rare observation is explained by the twisted and rigidified structure of the iminodibenzyl moiety.
关键词： dual emitter,quinoxaline,room temperature phosphorescence,iminodibenzyl,optical properties,mechanochromic,bridge effects,thermally activated delayed fluorescence,donor
更新于2025-09-19 17:15:36