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- 实验方案
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Near-infrared-light-triggered photoelectrochemical biosensor for detection of alpha-fetoprotein based on upconversion nanophosphors
摘要： A novel photoelectrochemical (PEC) biosensor based on hybrids of NaYF4:Yb, Tm， zinc oxide (ZnO) and cadmium sulfide (CdS) was constructed to detect alpha-fetoprotein (AFP), which possesses the advantages of low background noise and non-damage to the biological substance. Herein, we prepared NaYF4:Yb,Tm/ZnO/CdS composite film electrode by pulsed laser deposition. The selected materials of ZnO and CdS can make full use of the upconversion luminescence (~360nm, ~480nm) of NaYF4:Yb,Tm nanophosphors under 980nm laser excitation. Meanwhile, an effective matching of energy levels between the conduction bands of CdS and ZnO can prompt photoelectrochemical performance of the electrode. The biosensor shows ultrasensitive detection of AFP with a wide linear range from 0.01 ng mL-1 to 200 ng mL-1 and a low detection limit of 5 pg mL-1. Therefore, the proposed PEC biosensor based on upconversion nanophosphors is potentially attractive for achieving excellent photoelectrochemical biosensor for detection of other cancer markers in clinical analysis.
关键词： photoelectrochemical,pulsed laser deposition,upconversion luminescence,near-infrared light-triggered biosensor
更新于2025-11-14 15:27:09
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Enhanced upconversion luminescence intensity of core-shell NaYF4 nanocrystals guided by morphological control
摘要： How to further increase the upconversion luminescence (UCL) efficiency of core-shell upconversion nanoparticles (UCNPs) is highly desirable for their photoelectric and biological applications. Herein, a novel but facile strategy is proposed to substantially enhance the UCL intensity of NaYF4 based core-shell UCNPs by morphological control. The morphologies of core-shell UCNPs can be optimized from rod-like to spherical like by changing the ratio of oleic acid (OA) to 1-octadecene (ODE) during the shell growth process with other reaction conditions constant. The mechanism of shape control is further investigated based on the competitive absorption between OA molecules and lanthanide ions (Y3+, Yb3+, Er3+ or Tm3+) onto the different crystal axes (a, b and c) to guide their shell growth speed. The absolute quantum yields were up to 2.7 % and 1.8 % for spherical and rod like core-shell UCNPs under excitation of 980 nm laser (power density of 1.6 W/cm2), respectively. Moreover, the UCL intensity and effective lifetime (τeff) of Er3+ emission at 541 nm of spherical like core-shell UCNPs increased by 11.7 and 1.82 folds than rod like core-shell UCNPs. Therefore, our designed novel strategy can greatly improve the UCL efficiency of core-shell UCNPs and promote their development in diverse applications.
关键词： upconversion nanoparticles,upconversion luminescence,core-shell structure,morphological control
更新于2025-09-23 15:23:52
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Smartphone-based apparatus for measuring upconversion luminescence lifetimes
摘要： Luminescence lifetime detection plays an important role in time-resolved detection and research. However, the traditional instruments always require expensive detectors such as time-correlated single photon counter or streak camera. Herein, a low-cost and miniaturized apparatus for measuring upconversion luminescence lifetimes was developed by using a smartphone equipped with a 980 nm CW laser and a motor. When the motor was driving the sample circling at a high linear velocity, the excited sample would emit a luminescence arc, which could be photographed by the phone camera. The rotating rate could be measured by a tuner APP and then used for transferring arc length to delay times. By analyzing the grayscale distribution of the luminescence arc, the luminescence decay curve was obtained, which was then used for exponential fit and calculating lifetimes. The whole system was not only remarkably cheaper but also more miniaturized than traditional instruments for measuring luminescence lifetimes, indicating the promising applications in point of care testing for time-resolved luminescence detection for bioanalysis and disease diagnosis.
关键词： Lanthanide upconversion,Luminescence lifetime,Time-resolved,Motor,Smartphone
更新于2025-09-23 15:23:52
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Highly efficient green upconversion luminescence of ZnMoO4:Yb3+/Er3+/Li+ for accurate temperature sensing
摘要： Upconversion luminescence and optical temperature sensing properties of Yb3+/Er3+/Li+ tri-doped ZnMoO4 phosphors were investigated. It has been demonstrated that Li+ doping affected not only the local symmetry of Yb3+ and Er3+ but also the distribution of them in the host lattice. As a result, the significantly improved green upconversion luminescence was obtained when excited at 980 nm. The pumping power dependent photo-thermal behavior was used to evaluate the reliability of upconversion temperature sensing. An accurate temperature scale was established by eliminating the impact of thermal effect, and the sensing ability was evaluated via a comparison with the results reported in literatures.
关键词： Li+ doping,Upconversion luminescence,Thermal effect,Temperature sensing,ZnMoO4
更新于2025-09-23 15:23:52
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Physical principle and advances in plasmon-enhanced upconversion luminescence
摘要： In this review, we introduced the principle and advances in plasmon-enhanced upconversion luminescence. Firstly, we focus on the physical mechanism and principle of plasmon-enhanced upconversion luminescence, based on quantum electrodynamics. Secondly, we introduce in detail the advances in plasmon-enhanced upconversion luminescence, including plasmon-enhanced UC luminescence by metal/films, core-shell upconversion nanocrystals, plasmonic arrays/cavity and metal tip. Our review can not only promote deeper understanding quantum electrodynamics based plasmon-enhanced upconversion luminescence, but also can enlighten the potential applications of plasmon-enhanced upconversion luminescence.
关键词： Plasmon,Physical principle,Upconversion luminescence,Advances
更新于2025-09-23 15:23:52
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Excellent photoluminescence and temperature sensing properties in Ho3+/Yb3+ codoped (Y0.88La0.09Zr0.03)2O3 transparent ceramics
摘要： Ho3+/Yb3+ codoped (Y0.88La0.09Zr0.03)2O3 transparent ceramics were prepared by a high temperature solid-state reaction method. SEM observation confirms that there are no obvious impurities or pores existed in the grain boundaries of the samples. Accordingly, all the samples show excellent transparency in the visible and near-infrared range. Upon 980 nm excitation, strong green emission peaked at 549 nm, red emissions centered at 667 and 756 nm, as well as near infrared emission located at 2 μm respectively from Ho3+ ions are observed. By utilizing the fluorescence intensity ratio (FIR) technique, the temperature sensing behaviors of the optimal sample (Yb0.03Ho0.01Y0.84La0.09Zr0.03)2O3 are investigated at different excitation power densities based on the non-thermally coupled levels of 5F4/5S2 and 5F5. The thermometry is found to be immune to the excitation power density, leading to the consistent calibration curves and sensing sensitivities at the different power densities. The maximal sensing sensitivity is about 71.28×10?4 K?1 at 563 K. The results indicate that the Ho3+/Yb3+ codoped (Y0.88La0.09Zr0.03)2O3 transparent ceramics are promising for the temperature sensors, display devices and 2 μm solid-state lasers.
关键词： Upconversion luminescence,Rare earth,Optical thermometry,Transparent ceramics
更新于2025-09-23 15:23:52
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A highly sensitive photocatalytic plastic optic-fiber sensor for selective detection of phenol in aqueous solutions
摘要： We present a highly sensitive photocatalytic plastic optic-fiber (POF) sensor for the selective detection of phenol in aqueous solutions. To obtain high sensitivity and low limit of detection (LOD) of the sensor, part of the POF cladding was removed and replaced by a Canada balsam doped with GeO2 (CBG); a UV-visible-light-driven photocatalytic material, that is a CdS-sensitized Er3+YAlO3/SiO2/TiO2 (EYST) composite, was coated on the CBG film. To realize highly selective detection of phenol in water, a high phenol permselectivity and pH independence polymer membrane was fixed on the CdS-sensitized EYST-CBG-coated POF. Furthermore, a model was developed to show that the phenol concentration can be determined by measuring the change in transmitted light intensity of the POF sensor and the sensitivity of the sensors can be improved by employing the CdS-sensitized EYST film. The results showed that the proposed photocatalytic POF sensor has a high sensitivity of -0.39 (mg·mL-1)-1 and low LOD of 15 μg·L-1 for the selective detection of phenol in aqueous solutions with pH ranging from 2.0 to 14.0.
关键词： Cds sensitization,Phenol concentration,High sensitivity and selectivity,Upconversion luminescence agent,Plastic optical fiber,TiO2 composite film
更新于2025-09-23 15:23:52
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Upconversion luminescence properties of Y2O3: Yb3+/Er3+/Tm3+ nanocrystal doped PMMA nanocomposites
摘要： Y2O3 nanocrystals triply doped with Yb3+, Er3+, Tm3+ ions were synthesized via alginic acid-assisted gelation using thermal decomposition method and annealed at 800 °C for 24 h. Nanopowders were embedded into PMMA matrix via free-radical polymerization in an ultrasonic bath. X-ray diffraction and transmission electron microscopy measurements have shown that the crystal grain sizes decreased significantly with the narrow size distributions of the nanocrystals in PMMA matrix. A diode laser at 975 nm was used to measure the upconversion luminescence of the annealed nanopowders and those embedded in PMMA between the 400–850 nm wavelength region. The Er3+ concentration and the excitation power density dependencies of the relative intensities for red, green and blue upconversion luminescence in the nanopowder and PMMA nanocomposites are found to be different. The measured CIE-1931 color coordinates of the upconversion luminescence in PMMA nanocomposites show appreciable color stability under different excitation power densities, which is required for potential applications in the field of photonics.
关键词： Color Tunable Emission,Upconversion Luminescence,Polymer nanocomposites,Color Stability,Polymethyl methacrylate (PMMA)
更新于2025-09-23 15:21:21
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Color tunable upconversion luminescence and optical thermometry properties of mixed Gd2O3:Yb3+/Ho3+/Er3+ nanoparticles prepared via laser ablation in liquid
摘要： The mixtures of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles were successfully prepared via pulsed laser ablation in liquid followed by solution mixing. Under excitation of 980 nm diode laser, tunable color from green to red emission was achieved. Based on the thermal linked energy levels, the temperature sensitive upconversion emission was observed. The fluorescence intensity ratio (FIR) of I513–530 nm/I530–580 nm increased as the elevation of temperature. The absolute sensitivity and relative sensitivity were derived from temperature dependent FIR. The results show that the mixture of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles are not only potential candidates for multicolor upconversion luminescence but also promising optical materials for non-contact optical thermometry.
关键词： Gd2O3 nanoparticles,Color tunable emission,Pulsed laser ablation in liquid,Optical thermometry,Upconversion luminescence
更新于2025-09-23 15:21:01
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Controlled synthesis and upconversion luminescence properties of Yb3+/Er3+ co-doped Bi2O3 nanospheres for optical and X-ray computed tomography imaging
摘要： Bi2O3 nanospheres co-doped with Yb3t/Er3t upconverting ions pair have been successfully synthesized via a facile hydrothermal method followed by a heat treatment. The resulting Bi2O3:Yb3t,Er3t nanospheres show a monodisperse spherical morphology with narrow size distribution (~180 nm) and display intense upconversion luminescence under 980 nm laser excitation. It is found that the crystal structure, morphology and upconversion luminescence properties of nanospheres have a direct relationship with the doping concentration of Yb3t and the subsequent calcination temperature. These Bi2O3:Yb3t,Er3t nanospheres can be prepared in large quantities and can be easily modified with a layer of biocompatible polyethyleneimine (PEI) molecules. The yielded nanospheres could not only maintain uniform size and morphological characteristics, but also show good water dispersibility and biocompatibility. Remarkably, these Bi2O3:Yb3t,Er3t upconversion nanophosphors could also act as an effective contrast agent for X-ray computed tomography (CT) imaging, which show higher contrast efficacy than commercial iodine-based contrast agent. The proposed facile synthetic route and inexpensive matrix materials pave the way for broad use of these Bi2O3:Yb3t,Er3t nanospheres as ideal dual-mode bio-imaging probes in biomedical field.
关键词： Hydrothermal synthesis,CT imaging,Bi2O3,Upconversion luminescence,Nanophosphors
更新于2025-09-23 15:19:57