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White luminescent single-crystalline chlorinated graphene quantum dots
摘要： White luminescent materials have been generating much excitement because of their wide-ranging potential applications. However, challenging synthesis, cytotoxicity and performance of current reported white luminescent materials still hinder their potential applications. Owing to their non-toxicity, excellent optical properties, and amenability to surface modification, white-light-emitting graphene quantum dots (WGQDs) are considered to be a next-generation white luminescent material to replace these above-mentioned conventional materials. The inherent challenge in WGQDs is their massive defects are known to give poor white optical properties. In the proof-of-concept, we designed and synthesized a novel WGQDs via a solvothermal molecular fusion route. The modulation of chlorine doping amount and reaction temperature gives the WGQDs a single-crystalline structure, bright white fluorescence and novel white phosphorescence performance for the first time. An optimum fluorescence quantum yield of WGQDs is 34%, which exceeds the majority of reported WGQDs and other white luminescent materials. The WGQDs display broad-spectrum absorption within almost the entire visible light region, broad full width at half maximum and extend their phosphorescence emission to the entire white long-wavelength region. This unique dual-mode optical characteristic of the WGQDs enlarges their applications in white light emission devices, cell nuclei imaging, and information encryption.
关键词： solvothermal molecular fusion,white luminescent materials,fluorescence,graphene quantum dots,phosphorescence,chlorine doping
更新于2025-09-23 15:19:57
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Recent progress in phosphorescent Ir(III) complexes for nondoped organic light-emitting diodes
摘要： Highly efficient phosphorescent organic light-emitting diodes (PHOLEDs) with simple configuration as well as low cost fabrication process have attracted much interest for both academic researches and commercial endeavors. This review provides an update on recent advances in the development Ir(III) complexes and their applications in nondoped PHOLEDs fabricated by both vacuum deposition and solution-processed approaches. The modification of chemical structures of the small molecular Ir(III) complexes and dendrimers through incorporating multiple functional moieties could effectively adjust the optical and electronic characters. These complexes typically possess reduced intermolecular aggregation, various hole and electron transporting abilities so that high-performance nondoped PHOLEDs can be developed. The corresponding structural, optical, electronic, photophysical as well as the EL properties in different colors over the whole spectral region are surveyed and highlighted. In the end, the perspectives of the development for the further trend are presented, hopefully to provide useful guidance for the research on highly efficient Ir(III) complexes and corresponding nondoped PHOLEDs.
关键词： Organic light-emitting diode,Ir(III) complex,Nondoped devices,Phosphorescence
更新于2025-09-23 15:19:57
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Controlled Synthesis of PdII and PtII Supramolecular Copolymer with Sequential Multiblock and Amplified Phosphorescence
摘要： Supramolecular copolymers constitute a fundamental new class of functional materials attracting burgeoning interest, but examples that display phosphorescence and long-lived excited states are rare. Herein, we describe the synthesis of sequential phosphorescent multi-block supramolecular copolymers in one and multiple dimensions using pincer PtII and PdII complexes as building blocks by manipulating out-of-equilibrium self-assemblies via the living supramolecular polymerization approach. Doping a small amount of PtII complexes (2 mol %) into the PdII assemblies significantly boosted the emission efficiency and radiative decay rate constant (Fem = 3.7%, kr = 1.8 3 104 s?1 in PdII assemblies; Fem = 76.2%, kr = 58.6 3 104 s?1 in PtII-PdII co-assemblies), which is ascribed to an external heavy-atom spin-orbital coupling effect arising from the doped PtII complex with a delocalized 3[ds*/p*] excited state. The findings on PtII and PdII supramolecular copolymers with controlled sequences and greatly enhanced phosphorescence efficiencies open the door to new photofunctional and responsive luminescent metal-organic supramolecular materials.
关键词： Living supramolecular polymerization,PtII and PdII complexes,Phosphorescence,External heavy-atom effect,Supramolecular copolymers
更新于2025-09-23 15:19:57
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Homoleptic mer-Ir(III) complexes for highly efficient solution-processable green phosphorescent organic light-emitting diodes with high current efficiency
摘要： Two new highly efficient homoleptic green-emitting meridional iridium (III) complexes namely, mer-tris[5-hexyl-8-trifluoromethyl-5H-benzo(c)(1,5)naphthyridin-6-one]iridium(III) (mer-Ir1) and mer-tris[5-ethylhexyl-8-trifluoromethyl-5H-benzo(c)(1,5)naphthyridin-6-one]iridium(III) (mer-Ir2) were designed and synthesized at high temperature. These new Ir(III) complexes consist of amide bridged trifluoromethyl substituted phenylpyridine skeleton with longer alkyl chain. Interestingly, both Ir(III) complexes, mer-Ir1 and mer-Ir2 show bright green emission (λmax = 528 nm) with high photoluminescence quantum yields of 42 and 51% in solution at room temperature, respectively. Their thermal, photophysical, electrochemical, and electroluminescent (EL) properties were fully investigated. Both complexes were used as dopants for solution-processed green phosphorescence organic light-emitting diodes (PHOLEDs). Notably, the device using mer-Ir2 as new green dopant exhibited excellent EL performance with a maximum external quantum efficiency of 20.03% and maximum current efficiency of 67.81 cd A-1. To the best of our knowledge, this is the first time, particularly Ir(C^N)3 based mer-Ir(III) isomers showing excellent EL performance with high luminous efficiency in the green region via solution-processed PHOLEDs has been reported.
关键词： high photoluminescence quantum yields,current efficiency,external quantum efficiency,homoleptic green-emitting meridional iridium (III) complexes,solution-processed green phosphorescence organic light-emitting diodes (PHOLEDs)
更新于2025-09-23 15:19:57
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A thirty-fold photoluminescence enhancement induced by secondary ligands in monolayer protected silver clusters
摘要： In this paper, we demonstrate that systematic replacement of the secondary ligand PPh3 leads to an enhancement in the near-infrared (NIR) photoluminescence (PL) of [Ag29(BDT)12(PPh3)4]3?. While the replacement of PPh3 with other monophosphines enhances luminescence slightly, the replacement with diphosphines of increasing chain length leads to a drastic PL enhancement, as high as 30 times compared to the parent cluster, [Ag29(BDT)12(PPh3)4]3?. Computational modeling suggests that the emission is a ligand to metal charge transfer (LMCT) which is affected by the nature of the secondary ligand. Control experiments with systematic replacement of the secondary ligand confirm its influence on the emission. The excited state dynamics shows this emission to be phosphorescent in nature which arises from the triplet excited state. This enhanced luminescence has been used to develop a prototypical O2 sensor. Moreover, a similar enhancement was also found for [Ag51(BDT)19(PPh3)3]3?. The work presents an easy approach to the PL enhancement of Ag clusters for various applications.
关键词： photoluminescence enhancement,phosphorescence,secondary ligands,silver clusters,O2 sensor
更新于2025-09-19 17:15:36
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Investigation on the photophysical properties of a series of promising phosphorescent iridium (III) complexes with modified cyclometalating ligands
摘要： Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were applied to investigate the electronic structures and photophysical properties of a series of phosphorescent iridium (III) complexes, [(C^N)2Ir(N^N)]+(PF6)(cid:2), in which C^N = 4-aryl-1-benzyl-1H-1, 2, 3-triazoles. Herein, aryl = phenyl, biphenyl, three-phenyl aromatic for complexes 1a, 2a, 3a (N^N = 2, 20-bipyridine) and aryl = 40, 60-di?uorophenyl, 60-?uoro-biphenyl, 60-?uoro-three-phenyl aromatic for complexes 1b, 2b, 3b (N^N = 4, 40-di-tert-butyl-2, 20-bipyridine), respectively. The geometric/electronic con?gurations, absorption/emission properties and phosphorescent performances have been outlined for each of the complexes. Based on the two simpli?cations presented in this paper and the available experimental data, the phosphorescent radiative rates for complexes 1a-3b were approximately obtained to be: 1.20 (cid:3) 106 s(cid:2)1, 1.68 (cid:3) 105 s(cid:2)1, 2.19 (cid:3) 107 s(cid:2)1, 3.85 (cid:3) 106 s(cid:2)1, 1.85 (cid:3) 107 s(cid:2)1 and 1.50 (cid:3) 107 s(cid:2)1, respectively. In view of the electroluminescent applications in OLED, our present research work is of great importance for the design and synthesis of organo-transition metal complexes with improved phosphorescent performances.
关键词： Phosphorescence,Photophysical properties,Time-dependent DFT,Iridium (III) complexes,Density functional theory (DFT)
更新于2025-09-19 17:15:36
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Spectroscopic properties of Dy3+- and Dy3+, B3+- doped SrAl2O4
摘要： The dysprosium and boron effect on the emission properties of europium-doped SrAl2O4 samples has recently attracted considerable attention due to their high brightness and long afterglow. Here, the influence of both cations, Dy3+ and B3+, on the spectroscopic properties of the europium free samples SrAl2O4:Dy3+ and SrAl2O4:Dy3+, B3+ has been investigated in order to get more insights concerning the mechanism by which they enhance the afterglow. Unique features have been observed in their excitation and emission spectra that show on one hand the lattice defects induced by the replacement of Sr2+ by Dy3+ and proves the existence of different crystallography sites for the Dy3+ ions and on the other hand, the local distortion of the energy levels of Dy3+ ions in the presence of B3+.
关键词： Doping,Persistent phosphors,Dysprosium,SrAl2O4,Boron,Phosphorescence
更新于2025-09-19 17:15:36
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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
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A phenobarbital containing polymer/ silica coated quantum dot composite for the selective recognition of mercury species in fish samples using a room temperature phosphorescence quenching assay
摘要： An analytical procedure using low-cost instrumentation (fluorescence/phosphorescence spectrophotometer) has been developed to assess total mercury in fishery products. Determinations were based on the room temperature phosphorescence (RTP) quenching of a composite Ph-QDs consisting of phenobarbital-containing polymer/silica coated Mn-doped ZnS quantum dots. Under optimum conditions (fish extract pH of 8.0, Ph-QDs concentration of 20 mg L?1, and an interaction time of 12 min), the material offers high selectivity for inorganic mercury and methyl-mercury over other common ions present in the fish matrix. Moreover, good linearity was obtained for mercury concentrations within the 0–100 μg L?1 range, and the obtained limit of detection (68.2 μg kg?1) is low enough for a reliable assessment of total mercury in fish and seafood samples. The developed method was found to be free of matrix effects, and offers the advantage that the fish extracts can be directly analysed even at a 1:10 dilution. The method was found to be accurate after analysing a fish certified reference material, and after comparing total mercury levels in a set of fish samples analysed by the proposed chemosensor probe and by inductively coupled plasma mass spectrometry after an acid decomposition sample pre-treatment.
关键词： Room temperature phosphorescence,Phenobarbital,Fish,Mercury,Quantum dots
更新于2025-09-19 17:13:59
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Plasmonic Silver Nanoprism-Induced Emissive Mode Control between Fluorescence and Phosphorescence of a Phosphorescent Palladium Porphyrin Derivative
摘要： We have succeeded in significantly enhancing fluorescence from intrinsically phosphorescent palladium octaethylporphyrin (Pd-porphyrin) that has an intersystem crossing efficiency of ~1 by using silver nanoprisms (AgPRs). This was achieved by controlling the wavelength of localized surface plasmon (LSP) resonance of AgPRs and the distance between the Pd-porphyrin molecules and the AgPR surfaces. In addition to enhancing phosphorescence by spectrally overlapping the phosphorescence band with the LSP resonance band, tuning the LSP wavelength to approximately 520 nm led to the appearance of a new emission band around the wavelength corresponding to the fluorescent radiation. The appearance of fluorescence suggests that the nonradiative energy transfer from the singlet excited state of Pd-porphyrin to the LSP of AgPRs overcame the ultrafast intramolecular intersystem crossing to the triplet excited state, manifesting the spectral properties of the singlet excited state of Pd-porphyrin. The fluorescence nature of this radiation was strongly supported by lifetime measurements of the hybrids of Pd-porphyrin and AgPRs. Furthermore, the dependence of the emissive intensities on the distance between the Pd-porphyrin molecules and the AgPR surfaces showed interesting opposite trends. The fluorescence intensity was increased as the distance between the molecules and the AgPRs was decreased from 10.5 nm to 1 nm, while the phosphorescence intensity was decreased, which indicates that the LSP-induced fluorescence radiation process from Pd-porphyrin near the AgPRs outweighed the quenching by the AgPRs, even though the phosphorescence significantly suffered quenching.
关键词： silver nanoprisms,localized surface plasmon resonance,palladium porphyrin,phosphorescence,metal-enhanced fluorescence,fluorescence,intersystem crossing
更新于2025-09-19 17:13:59