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- 2018
- electron-transparent membranes
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- ion mobility spectrometry
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- Optoelectronic Information Science and Engineering
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- Physics
- Wroclaw University of Science and Technology
- Beijing Vacuum Electronics Research Institute
- Sun Yat-sen University
- University of Surrey
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Benzo[ghi]perylene & Coronene as Ratiometric Reversible Optical Oxygen Nano-Sensor
摘要： The development of novel single molecular probe based optical ratiometric oxygen sensor with simple fabrication, high sensitivity, and linear response is highly desirable. Herein, benzo[ghi]perylene (BzP) and coronene (Cron) were explored as dual-emissive ratiometric oxygen nano-sensor that displayed linear plots at a low probe concentration (6 μM). The sensor fabrication was simple, and the probes exhibited efficient fluorescence quenching of monomer emission by molecular oxygen. However, the excimer emission of probe remained unaffected. Thus a ratiometric method is developed based on the dual emitting luminophore. The method can be used to estimate dissolved oxygen in liquids and 5 – 100 % of oxygen concentration in gaseous mixtures.
关键词： Coronene,Benzo[ghi]perylene,Oxygen sensing,Excimer emission,Ratiometric sensor,Fluorescence probe
更新于2025-11-14 17:04:02
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Alcohol-Guided Growth of Two-Dimensional Narrow-Band Red-Emitting K2TiF6:Mn4+ for White Light-Emitting Diodes
摘要： The use of red phosphors with low light-scattering loss could improve the luminous efficacy and color rendering of white light-emitting diodes (LEDs). Thus, the discovery of such phosphors is highly desired. In this work, high-efficiency two-dimensional red-emitting K2TiF6:Mn4+ (KTFM) were synthesized via an alcohol-assisted coprecipitation route. The synergistic effects of 1-propanol and hydrofluoric acid (HF) on the growth of KTFM microsheets (MSs) were studied through the first-principles calculations, which revealed that 1-propanol promoted the growth of KTFM MSs by preferentially adsorbing on the H-terminated K2TiF6 (001) surface. The photoluminescence quantum efficiency (QE) of Mn4+-activated K2TiF6 MSs was highly related to their size and thickness. The morphology-optimal KTFM MSs presented high internal QE (> 90 %), external QE (> 71%), and thermal quenching temperature (102% at 150 °C relative to that at 25 °C). A prototype phosphor-converted LED with KTFM as the red-emitting component showed an excellent color rendition (Ra = 91, R9 = 79) and high luminous efficacy (LE =156 lm/w).
关键词： light emitting diode,two-dimensional material,Narrow band,K2TiF6:Mn4+,backlight,red emission
更新于2025-11-14 17:04:02
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Correlation of acetylene plasma discharge environment and the optical and electronic properties of the hydrogenated amorphous carbon films
摘要： Thin films from polymeric and graphitic hydrogenated amorphous carbon (a-C:H) were deposited over a glass substrate from acetylene (C2H2) plasma by using a conventional plasma enhanced chemical vapor deposition (PECVD). Radio frequency capacitively coupled plasma (RF CCP) source operating at a frequency of 13.56 MHz was used for generation of the discharge. Optical emission spectroscopy (OES) results showed strong optical emissions from diacetylene ion C4H2+ at a wavelength of 506 nm. The energy dispersive X-Ray (EDS) measurements illustrated that the carbon content in the deposited films increased with increasing of power. The Raman and IR results demonstrated that the films deposited at low bias voltages 340 V are so called polymeric a-C:H with high sp3 fraction and high hydrogen content, while the films deposited at high bias voltages 877 V are so called graphitic a-C:H with low sp3 fraction and low hydrogen content. Quantitative information were obtained from fitting the high asymmetrical vibrational modes of Raman and IR spectra by using Fano model expression together with Lorentzian function. The results presented here point out that there is a relation between the intensity of C4H2+ ion emissions and the deposited films properties.
关键词： Optical Emission,diacetylene ion,RF CCP,Hydrogenated amorphous carbon,FTIR,Raman spectroscopy
更新于2025-11-14 15:30:11
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Optical Characterization of Doped Thermoplastic and Thermosetting Polymer-Optical-Fibers
摘要： The emission properties of a graded-index thermoplastic polymer optical fiber and a step-index thermosetting one, both doped with rhodamine 6G, have been studied. The work includes a detailed analysis of the amplified spontaneous emission together with a study of the optical gains and losses of the fibers. The photostability of the emission of both types of fibers has also been investigated. Comparisons between the results of both doped polymer optical fibers are presented and discussed.
关键词： polymer optical fibers,thermoplastic fibers,rhodamine 6G,light-emitting polymers,optical gain,amplified spontaneous emission,thermosetting fibers
更新于2025-11-14 15:30:11
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Cross-linking induced thermoresponsive hydrogel with light emitting and self-healing property
摘要： Development of self-healing hydrogels with thermoresponse is very important for artificial smart materials. In this article, the self-healing hydrogels with reversible thermoresponse were designed through cross-linking-induced thermoresponse (CIT) mechanism. The hydrogels were prepared from ketone group containing copolymer bearing tetraphenyl ethylene (TPE) and cross-linked by naphthalene containing acylhydrazide cross-linker. The mechanical property, light emission, self-healing, and thermo-response of the hydrogels were investigated intensively. With regulation of the copolymer composition, hydrogels showed thermoresponse with the LCST varied from above to below body temperature. At the same time, the hydrogels showed self-healing property based on the reversible characteristic of the acylhydrazone bond. The hydrogel also showed temperature-regulated light emission behavior based on AIE property of the TPE unit.
关键词： TPE,cross-linking-induced thermoresponse,hydrogel,self-healing,light emission
更新于2025-11-14 15:27:09
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Cross-linking induced thermo-responsive self-healable hydrogels with temperature regulated light emission property
摘要： Self-healing hydrogels draw great attentions in past decade based on the self-healing property similar to living creatures and their potential application in bioscience. On the other hand, thermo-response of the hydrogel endow the hydrogel with smart characteristic for controlled drug loading and delivery, diagnosis, cell imaging, life simulation, etc. In this study, self-healable hydrogel with cross-linking induced thermo-response (CIT) property was prepared from TPE containing copolymer TPE-P(DMA-stat-DAA) and the LCST of the hydrogels could be regulated by copolymer composition and the structure of the cross-linkers. The light emission property, mechanical and self-healing performances of the hydrogels are also investigated intensively. The results showed the LCST of the hydrogels could be regulated to body temperature through cross-linking induced thermo-response (CIT) mechanism with PEO23 DNH cross-linking. At the same time, the hydrogels exhibit light emission property, excellent self-healing ability and good mechanical properties. Moreover, the hydrogels showed different light emission property regulated by temperature based on AIE property of the TPE.
关键词： Light emission,Self-healing hydrogel,Cross-linking induced thermo-response
更新于2025-11-14 15:26:12
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Fluorometric determination and intracellular imaging of cysteine by using glutathione capped gold nanoclusters and cerium(III) induced aggregation
摘要： A turn-on fluorometric method is described for selective and sensitive detection of cysteine (Cys). Gold nanoclusters (Au NCs) capped with glutathione (GSH) are used as a fluorescent probe. If Ce3+ ion are present, they will bind to the carboxy groups of the GSH-capped Au NC. This results in aggregation-induced emission enhancement (AIEE), best measured at excitation/emission wavelengths of 360/575 nm. On addition of Cys, which has less steric hindrance compared with GSH and higher affinity for Ce3+, it will bind to Ce3+ through the carboxyl group and link with Au NCs via Au-S bond. Hence, the AIEE is increased and Cys can be quantified via this effect with a linear response in the 0.4–120 μmol L?1 Cys concentration range and a detection limit of 0.15 μmol L?1.
关键词： Au NC,HepG2 cell imaging,Aggregation-induced emission enhancement
更新于2025-11-14 15:26:12
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Complementary use of pulsed and continuous wave emission modes to stabilize melt pool geometry in laser powder bed fusion
摘要： The most common defects in laser powder bed fusion (LPBF) namely porosity, geometrical errors, roughness and thermal deformations are principally linked with the energy input to the process. In common practice, a single set of process parameters is used to produce a whole component independently from the dimensions of the actual scan path within a given layer. However, melt pool stability is highly dependent on the scanned geometry. A possible strategy to maintain a constant melt pool is the mixed use of pulsed wave (PW) and continuous wave (CW) emission regimes. Accordingly, this work investigates the complementary use of continuous and modulated emission at fixed energy density on large and thin sections respectively. The proposed approach is tested on AISI 316L stainless steel and melt pool observations are conducted employing a coaxial monitoring system built for purpose. Temporally resolved measurements of intensity and geometrical properties of the melt pool were extracted as well as a three-dimensional spatial mapping of the molten pool area. The results demonstrate that moving from CW to a PW regime at the transition zones to thinner sections is effective in maintaining a constant melt pool size thus avoiding heat build-up and part extrusion from the powder bed.
关键词： Selective laser melting,Stainless steel,Molten pool monitoring,CW emission,PW emission
更新于2025-11-14 15:24:45
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Effects of the emission layer structure on the electroluminescence performance of the white organic light emitting diodes based on thermally activated delayed fluorescence emitters
摘要： White organic light emitting diodes (WOLED) employing blue, green and red thermally activated delayed fluorescence (TADF) emitters of DMAC-DPS(B), 4CzIPN(G) and 4CzTPN-Ph(R) are fabricated and the effects of the emission layer (EML) structure, including EML thickness and 4CzTPN-Ph(R) dopant concentration, on the electroluminescence (EL) performance of G/B, G/R/B and R:G/B are investigated. It is found that the WOLED with the simple EML structure of G(20nm)/B(10nm) demonstrates maximum power efficiency (PE) around 16 lm/w and color rendering index (CRI) of 81. Meanwhile, R:G/B EML exhibits better EL performance than that of G/R/B EML. Especially, striking high CRI of 90 together with maximum PE around 13 lm/w can be obtained for R(1wt%):G(20nm)/B(10nm) EML by meticulously modulation of EML thickness and 4CzTPN-Ph(R) dopant concentration, indicating the achievement of balance between EL efficiency and CRI for non-doped TADF emitter-based WOLED. Furthermore, the stacked EML of G(20nm)/R(0.1nm) and G(20nm)/R(0.1nm)/B(10nm) reveal much more serious obstruction of delayed fluorescence (DF) compared to mixed EML of R(1wt%):G(20nm) and R(1wt%):G(20nm)/B(10nm), implying more intensified quenching effects from the sandwiched 0.1nm 4CzTPN-Ph(R) layer which will lead to deterioration of EL performance. Different photoluminescence (PL) and transient PL decaying dynamics derived from the sandwiched 4CzTPN-Ph(R) ultrathin layer is found to be critical. The decaying dynamics responsible for such EML structure dependent EL performance is discussed in details.
关键词： WOLED,TADF,emission layer (EML),decaying dynamics
更新于2025-11-14 15:24:45
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Solvent-Dependent Sensitization of Ytterbium and Neodymium via an Intramolecular Excimer
摘要： We report the synthesis of a di(1-pyrenyl)-phosphoryl acetophenone ligand containing two pyrenyl moieties linked by a single phosphorus atom. The ligand exhibits solvent-dependent emission: in nonpolar solvents, typical monomeric pyrene emission is observed, whereas in polar solvents, an additional broad and structureless emission appears. The emission in polar solvents is concentration independent and is attributed to the emission of an intramolecular excimer. The coordination of the di(1-pyrenyl)phosphoryl acetophenone ligand as well as the corresponding deprotonated anionic di(1-pyrenyl)phosphoryl acetophenonate ligand was studied with the near-infrared emitting lanthanides, neodymium and ytterbium. Solvent-dependent sensitization of both lanthanides was observed and correlates with the presence of the excimer emission. Sensitization of ytterbium is more efficient than neodymium, and the overall quantum yields were found to be 12.8 and 1.9% for ytterbium and neodymium, respectively.
关键词： solvent-dependent emission,quantum yields,ytterbium,neodymium,intramolecular excimer,lanthanides
更新于2025-11-14 15:24:45