- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Hydrothermal Synthesis and Upconversion Properties of About 19?nm Sc2O3: Er3+, Yb3+ Nanoparticles with Detailed Investigation of the Energy Transfer Mechanism
摘要： The Sc2O3: Er3+, Yb3+ nanoparticles (NPs) with the size of about 19 nm were synthesized by a simple oleic acid-mediated hydrothermal (HT) process. X-ray diffraction (XRD), transmission electron microscopy (TEM), upconversion luminescence (UCL) spectra, and decay curves were used to characterize the resulting samples. The Sc2O3: Er3+, Yb3+ NPs made by HT method exhibit the stronger UCL, of which the red UCL are enhanced by a factor of 4, in comparison with those samples prepared by solvothermal (ST) method at the same optimized lanthanide ion concentrations. The UCL enhancement can be attributed to the reduced surface groups and longer lifetimes. Under 980 nm wavelength excitation, the decay curves of Er3+: (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 emissions for Sc2O3: Er3+, Yb3+ NPs samples are both close to each other, resulting from the cross relaxation energy transfer from Er3+ to Yb3+, followed by an energy back transfer within the same Er3+-Yb3+ pair. Also, under the relatively low-power density, the slopes of the linear plots of log(I) vs. log(P) for red and green emissions are 2.5 and 2.1, implying the existence of three-photon processes. Our results indicate that Sc2O3: Er3+, Yb3+ NPs is an excellent material for achieving intense UCL with small size in the biological fields.
关键词： Hydrothermal synthesis,Upconversion,Sc2O3,Energy transfer,Er3+/Yb3+
更新于2025-09-11 14:15:04
-
[IEEE 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Ottawa, ON, Canada (2019.7.8-2019.7.12)] 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Graphene Multilayers for Quantum Microwave Signal Up-Conversion to the Optical Domain
摘要： We propose a new scheme for tunable quantum microwave signal upconversion to the optical frequency domain using graphene multilayers. The graphene layers are electrically connected, biased by a quantum level microwave signal, and subjected to intensive optical pump. The principle of operation is based on modifying the graphene conductivity by the biasing microwave signal. It then follows that an upper optical sideband is generated, while the lower sideband is resonantly attenuated by the destruction of the layered medium . Our calculations show large number of upconverted photons for microvolt driving microwave signal.
关键词： quantum microwave signal,graphene multilayers,optical frequency domain,upconversion
更新于2025-09-11 14:15:04
-
Triplet‐Triplet Annihilation Upconversion in a MOF with Acceptor‐filled Channels
摘要： Photon upconversion enjoys an increasing interest in the last years due to its high potential for solar energy harvesting and in bio-imaging. A challenge for triplet-triplet annihilation upconversion (TTA-UC) processes is to realize these features in solid materials without undesired phase segregation and detrimental dye aggregation. To achieve this, we combine a palladium porphyrin sensitizer and a 9,10-diphenylanthracene annihilator within a crystalline mesoporous metal-organic framework using an inverted design. In this modular TTA system, the framework walls constitute the fixed sensitizer, while caprylic acid coats the channels providing a solvent-like environment for the mobile annihilator in the channel. The resulting solid material shows green-to-blue delayed upconverted emission with a luminescence lifetime of 373±5 μs, a threshold value of 329 mW cm–2 and a triplet-triplet energy transfer efficiency of 82%. The versatile design allows straightforward changing the acceptor amount and type.
关键词： triplet-triplet annihilation,porphyrins,metal-organic frameworks,upconversion,hybrid materials
更新于2025-09-11 14:15:04
-
Enhanced photovoltaic performance of Y2O3:Ho3+/Yb3+ upconversion nanophosphor based DSSC and investigation of color tunability in Ho3+/Tm3+/Yb3+ tridoped Y2O3
摘要： The present study reports the upconversion (UC) based color tuning in Y2O3:Ho3+/Yb3+, Y2O3:Tm3+/Yb3+ and Y2O3:Tm3+/Ho3+/Yb3+ phosphors synthesized through complex based precursor solution method. The Y2O3:Ho3+/Yb3+ phosphor emits intense green and weak red colors whereas the Y2O3:Tm3+/Yb3+ emits NIR and blue colors on excitation with 976 nm. The impact of the enhancement in the concentration of Yb3+ on the color point of codoped as well as tridoped phosphors has been studied in detail. When Y2O3:Tm3+/Ho3+/Yb3+ phosphor is excited by 976 nm laser, the phosphor emits dominant green color. This is due to energy transfer from Tm3+ to Ho3+ ions. The increase in the concentration of Yb3+ ion leads to a color tunability not only in the co-doped but also in the tridoped phosphors. Furthermore, we have incorporated Y2O3:Ho3+,Yb3+ UC phosphor into TiO2 electrode to form an UC based DSSC for converting near IR (NIR) light into visible where DSSCs typically have high sensitivity. The short-circuit current density (Jsc) as well as the open-circuit voltage (Voc) of the UC-TiO2 based cell was found to be 8.46% and 5.18% higher which in turn, resulted into a 10.33% enhancement in power conversion efficiency as compared to that of bare TiO2 based DSSC. Thus, the UC based Y2O3:Ho3+/Yb3+ may be useful in color tunability and DSSC applications.
关键词： Upconversion,Photovoltaic performance,Color tuning,DSSC,Y2O3:Ho3+/Yb3+
更新于2025-09-11 14:15:04
-
Enhanced upconversion luminescence in controllable self-assembled BiOBr: Yb3+/Er3+ 3D hierarchical architectures and their application in NIR photocatalysis
摘要： In this work, self-assembled Yb3+/Er3+ co-doped BiOBr 3D flower-like hierarchical architectures (HAs) were synthesized via hydrothermal method. With increasing pH values, the thickness of samples became thinner, and the morphology transforms from 2D nanosheets to self-assembled 3D HAs. Under the excitation of 980 nm, 3D flower-like BiOBr: Yb3+/Er3+ HAs showed a significant enhancement the upconversion (UC) emission, which was about 505 times than that of the 2D nanosheets. The mechanisms for the enhancement of UC emission have been discussed. Moreover, all the samples showed effective photocatalytic activity for the RhB degradation and obviously enhanced performance with increasing pH values under NIR and simulated solar light irradiation, due to the internal electric field effects and efficient utilization of UC emissions. This work gives insight to the guidance of fabricating efficient self-assembled 3D flower-like BiOBr: Yb3+/Er3+ HAs UC materials, which have great potential for the applications in NIR-activated photocatalysts.
关键词： upconversion,BiOBr: Yb3+/Er3+,morphology,NIR-activated photocatalysts
更新于2025-09-11 14:15:04
-
Effect of Li co-doping with Er on up-conversion luminescence property and its temperature dependence of NaY(WO4)2
摘要： NaY(WO4)2 phosphors with different Er3+ doping and Er3+/Li+ co-doping concentrations were prepared via high temperature solid state reaction. X-ray diffraction measurement demonstrated the presence of tetragonal-phase NaY(WO4)2, and no impurity phase was found in Er3+/Li+ co-doped samples. Well-crystallized NaY(WO4)2 phosphors showed a fine morphology with particle sizes of 1–6 μm determined by scanning electron microscope. Under excitation at 980 nm, the origins of three emission peaks located at 527 nm (green emission 1), 549 nm (green emission 2) and 665 nm (red emission), respectively, were identified. By introducing Li+, the up-converted (UC) emission intensity was enhanced by 0.5 times and 2 times in green and red emission region, respectively. The enhanced luminescence was attributed to the distortion of the local symmetry around Er3+ due to Li+ incorporation in the lattices. The 2H11/2 → 4I15/2 (green emission 1) and 4S3/2 → 4I15/2 (green emission 2) transitions of the Er3+ ion presented a temperature dependent behavior from 300 to 30 K and were proposed for temperature sensing (optical thermometry) by using the fluorescence intensity ratio (FIR) method. The FIR data obtained by experiment was well fitted with a theoretical function. A higher maximum value of sensitivity (0.0061 K-1) was obtained in 5% Er3+, 0% Li+ doped sample at 300 K. However, due to the distortion of local crystal field around Er3+ ions caused by the introduction of Li+, the sensitivity value of 5% Er3+ and 1% Li+ co-doped sample was higher than that of Li+ free sample below 270 K, which indicated that appropriate Li+ co-doping could optimize the temperature sensing behaviors of Er3+ doped NaY(WO4)2 phosphors.
关键词： Upconversion photoluminescence,Li+ co-doping,Alkaline earth oxides,Temperature sensing
更新于2025-09-10 09:29:36
-
Yb3+/Tb3+/Ho3+: phosphate nanophase embedded glass ceramics: enhanced upconversion emission and temperature sensing behavior
摘要： Yb3+/Tb3+/Ho3+ tri-doped transparent phosphate glass–ceramics (GCs) were successfully synthetized by a conventional melt-quenching technique with subsequent glass crystallization. The formation of phosphate nanocrystals (NCs) with leucite structure was confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected-area electron diffraction (SAED). The variation of the decay curves confirms the accumulation of active centers into the NCs lattice. Hence, the UC emission intensity of Yb3+/Tb3+/Ho3+ doped GC610 sample is greatly enhanced relative to that in precursor glass (PG). And the UC energy transfers processes were systematically analysis. The result shows that the energy transfer of Ho3+→Tb3+ exists while Yb3+ as a sensitizer ion. Furthermore, the temperature-dependent UC luminescence and temperature sensing behaviors of the prepared materials based on the thermally coupled levels of Tb3+: 5D4 and Ho3+: 5F5 in the temperature range of 298–648 K were systematically investigated, to explore its possible application as optical thermometric medium, by utilizing the fluorescence intensity ratio (FIR) technique. The relative sensitivity (Sr) of 7.5 × 10?3 K?1 and absolute sensitivity (Sa) of 22 × 10?3 K?1 are achieved in the Yb3+/Tb3+/Ho3+ tri-doped GC. This GC materials is a very promising candidate for optical temperature sensors.
关键词： Yb3+/Tb3+/Ho3+ tri-doped,phosphate glass–ceramics,upconversion emission,temperature sensing,optical thermometry
更新于2025-09-10 09:29:36
-
Augmenting nitrogen removal by periphytic biofilm strengthened via upconversion phosphors (UCPs)
摘要： The application of periphytic biofilm in removing nitrogen from water is limited by the fluctuating nitrogen concentration. Here, we delineate a novel approach to enhance periphytic biofilm performance in nitrogen removal via upconversion luminescence of upconversion phosphors (UCPs). Nitrogen removal rates (14 d) in high nitrogen wastewater (26 mg/L) were significantly improved to 58.6% and 61.4% by UCPs doped with Pr3+ and Li+ and UCPs doped with Pr3+, respectively, and to 95.1% and 95.9% in low nitrogen surface water (2 mg/L), respectively. The stimulation of UCPs optimized the microbial community structure in the periphytic biofilms, and also resulted in good acclimation to use different carbon sources. The enhanced synergic action of cyanobacterial biomass, ratio of Gram +ve to Gram -ve bacteria and carbon source metabolic capacity contributed to the improved nitrogen removal. This novel approach is promising in nitrogen removal from wastewater and surface water with fluctuating initial nitrogen concentration.
关键词： Nitrogen removal,Microbial aggregates,Upconversion luminescence,Microbial community structure,Periphytic biofilm
更新于2025-09-10 09:29:36
-
CaTiO3:Er3+:Yb3+ Upconversion from 980 nm and 1550 nm Excitation and its Potential as Cells Luminescent Probes
摘要： CaTiO3:xEr3+:yYb3+ (x = 0.3mol%; y = 1.0, 1.5 and 2.0 mol%) was synthesized by the sol-gel process. Crystal phase purity, crystallite sizes and microstrain were evaluated as a function of rare earths concentration through XRD and SEM techniques. Upconversion (UC) spectra were recorded at 300 K under excitation at 980 nm and 1550 nm. The samples showed higher intensity of green emission assigned to the upconversion phenomena compared to the red one, when excited at 980 nm and the opposite was observed when excitation was performed at 1550 nm. The nanoparticles CaTiO3:Er3+:Yb3+ were successfully applied as animals cells cytoplasm staining luminescent probes, with low cytotoxic effect being observed. Er3+ emission at 1550 nm was also proposed for in vitro or in vivo optical imaging analysis in the so-called second window (1350 - 2300 nm).
关键词： ytterbium,calcium titanate,erbium,fluorescent cell dyeing,upconversion
更新于2025-09-10 09:29:36
-
Alkaline-Earth Fluorohalide Nanocrystals for Upconversion Thermometry
摘要： The temperature-dependent luminescence response of SrFCl:Yb,Er and SrFBr:Yb,Er upconverting nanocrystals was investigated with an eye towards the expansion of the library of host materials for optical thermometry. Steady-state and luminescence decays of the 2H11/2 and 4S3/2 thermally coupled levels of the Er3+ activator were probed in the 100?450 K temperature range. Fluorescence intensity ratios and thermometric sensitivities were extracted in two temperature regimes. In the low-temperature regime, SrFCl:Yb,Er and SrFBr:Yb,Er displayed maximum sensitivities of 3.2 × 10?2 K?1 (125 K) and 2.1 × 10?2 K?1 (175 K), respectively. In the high-temperature regime, sensitivities were comparable to those observed in upconverting nanocrystals such as NaYF4:Yb,Er at room temperature, with values of 9.4 × 10?3 K?1 (325 K) for SrFCl:Yb,Er and 1.1 × 10?2 K?1 (300 K) for SrFBr:Yb,Er. The observed temperature-dependent responses resulted from long- and short-lived Er3+ emitters present in both fluorohalide hosts. For each type of emitter, radiative constants and activation energies for thermal quenching of the emission from the 4S3/2 level were estimated using a single-barrier quenching model. The local atomic environments of the long- and short-lived Er3+ emitters differed to a greater extent in SrFCl:Yb,Er than in SrFBr:Yb,Er.
关键词： SrFBr,Nanocrystals,Thermometry,SrFCl,Upconversion,Rare-earth
更新于2025-09-10 09:29:36