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Highly -sensitive near infrared luminescent nanothermometers based on binary mixture
摘要： We propose a simple strategy to obtain a luminescence intensity ratio nanothermometer operating in the near infrared range (1000 – 1700 nm) by use of binary mixtures of lanthanide doped Y2O3 selected as 1%Ho - Y2O3 + 1%Er - Y2O3 and 1%Ho - Y2O3 + 1%Nd - Y2O3. All nanoparticles were synthetized by citrate complexation method and thermally annealed at 800 °C. The temperature evolution of the emission properties was monitored in the range of 297 – 472 K and analyzed in terms of emission shape, intensity, dynamics, excitation wavelength, acquisition mode and weight ratio of the binary mixture. A maximum relative sensitivity of 1%K-1 at 297 K was recorded for the 3:1 weight ratio Ho – Y2O3 + Er – Y2O3 binary mixture upon excitation at 536.8 nm. For the more appropriate excitation wavelength for bioimaging applications at 649.7 nm, a relative sensitivity of 0.55 - 0.6 % K-1 was recorded in the relevant physiological temperature range (300 -320 K) for the 3:1 weight ratio Ho – Y2O3 + Er – Y2O3 binary mixture. To the best of our knowledge, our study also represents a first report on the near -infrared luminescence (around 1200 nm) lifetime thermometry for a Ho doped nanoparticle. Comparison with the literature demonstrates that our system represents a promising near-infrared thermometer, with a non-sophisticated and reproducible configuration that is open to multiple optimization routes.
关键词： Lifetime thermometry,Binary mixture,lanthanide doped Y2O3,Near infrared luminescence,Self-referenced nanothermometry
更新于2025-09-23 15:22:29
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Characterization and removal of antibiotic residues by NFC-doped photocatalytic oxidation from domestic and industrial secondary treated wastewaters in Meric-Ergene Basin and reuse assessment for irrigation
摘要： Antibiotics are important contaminants that have become an increasingly big problem due to the discharge of the receiving environment. The presence of these organic based pollutants in influent wastewater can inhibit the biological processes and resist to degradation in wastewater treatment plants. Moreover, the consumption of agricultural products, irrigated with water containing antibiotic residues, leads to major harmful effects to the human body through the food chain. In this study; firstly, a conventional characterization was made in terms of COD, TOC, SS, color and of antibiotic residue characterization of untreated raw (influent) and biologically treated (effluent) water from domestic and industrial wastewater treatment plants located in the Meri?-Ergene Basin. After that, photocatalytic activity test was run under visible light for selected antibiotics (Erythromycin, Ciprofloxacin, Sulphametoxasol) which were detected by HPLC MS/MS in excess amount. Finally, for the photocatalytic oxidation, a new generation NFC (Nitrogen-Floride-Carbon)-doped titanium dioxide photocatalyst, which has never been studied in the literature before, was prepared according to the sol-gel method without using thermal processing. Photocatalysts were characterized by UV–vis DRS reflectance and Laser Raman Spectra measurements. All other analyzes were made according to the standard methods. Considering the conventional characterization results; investigated domestic wastewaters exhibited moderate characteristics while industrial wastewater samples had strong characteristics in terms of COD, TOC and SS pollution in accordance with the literature. By the way, contrary to expectations, antibiotic residue results have proved that the effluent wastewater contains more antibiotics than the influent. This can be explained by the fact that, some antibiotics in domestic wastewaters are probably already trapped in feces and cannot be purified by conventional systems since they are released after biological treatment, as mentioned similar studies in the literature. Moreover, by means of 7 h NFC-doped photocatalytic oxidation under visible light, beside approximately % 62 to %79 COD and 62%–86% TOC removal, %99 to %100 removal of antibiotic residue was provided. According to these results, domestic and industrial secondary treated wastewaters in Meric-Ergene Basin can be advance treated, succesfully, with NFC-doped photocatalyst to remove antibiotic residues besides conventional pollutants. This result show that Meri?-Ergene discharge criteria determined by Forest and Water Ministry of Turkey can be provided with this new type photocatalytic process and healthy reuse of this river for irrigation will be possible.
关键词： Advanced oxidation processes,Domestic/industrial wastewater,Solvent-casting method,UV,Antibiotic,Photocatalyst,NFC-doped TiO2
更新于2025-09-23 15:22:29
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Optical, structural and luminescence properties of oxyfluoride phosphate glasses and glass-ceramics doped with Yb3+
摘要： The impact of Al2O3 and Y2O3 addition on the structure, Yb3+ luminescence and crystallization is investigated for glasses in the P2O5-SrO-Na2O system. Although the addition of Al2O3 and Y2O3 leads to a more connected phosphate network as evidenced using IR and Raman spectroscopies and increases the glass transition temperature, it does not affect strongly the site of the Yb3+. The addition of Al2O3 and Y2O slightly decreases the rate of the glass crystallization. Surface crystallization occurs upon heat treatment. Crystallization was confirmed by the presence of sharp peaks in the XRD patterns of the glasses. Independently of the glass composition, multiple different crystalline phases precipitate in the glasses upon heat treatment. The precipitation of the Na1O7P2Yb1 crystal phase leads to an increase of the excited state 2F5/2 lifetime of Yb3+ and also of the bandwidth of the Yb3+ emission band centered at 1μm.
关键词： nucleation and growth,Yb3+ doped phosphate glasses,Raman & Infrared spectroscopies,Yb3+ luminescence properties,heat treatment
更新于2025-09-23 15:22:29
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Newly developed chromium-doped fiber as a saturable absorber at 1.55- and 2.0-μm regions for Q-switching pulses generation
摘要： We demonstrate a Q-switching operation laser at 1.55- and 2-μm region using a homemade 10 cm long of Chromium-doped ?ber (CrDF) as a passive saturable absorber (SA). Erbium-doped ?ber (EDF) and Thulium-doped ?ber (TDF) as a gain medium cooperate in the all-?ber ring cavity con?guration. CrDF was fabricated by Modi?ed Chemical Vapour Deposition (MCVD) technique in conjunction with conventional solution doping (SD) method. The CrDF has a saturable absorption of 9% at 1.55-μm region with a saturation intensity of 22 MW/cm2. Therefore, a stable pulse train obtainable within 75–173 mW, with a repetition rate increases from 68.12 kHz to 115.9 kHz. At the maximum pump level, a shorter pulse width, maximum output power, and maximum pulse energy are 3.85 μs, 10.86 mW, and 94.1 nJ, respectively. In TDF laser cavity, the laser pulsing generates from 363 mW to 528 mW, where the repetition rate increases from 13.02 kHz to 27.62 kHz. At maximum pump power, a shorter pulse width, maximum output power, and pulse energy are obtained with 4.48 μs, 6.36 mW, and 230.27 nJ, respectively. Both pulse trains at 1.55- and 2-μm region are stable with a signal-to-noise ratio (SNR) of 71 dB and 44 dB, respectively. These ?ndings are important to the discovery of robust passive saturable absorber development in a form of ?ber which has a similar melting point to the rest of the silica ?ber in the proposed cavities. Thus, it will be a kick-started to alternative form of passive SAs in developing a future high-power ?ber lasers.
关键词： Pulse laser,Ring cavity,Chromium-doped ?ber saturable absorber,Fiber laser
更新于2025-09-23 15:22:29
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Cobalt/Molybdenum Phosphides and Oxides Heterostructures Encapsulated in N-doped Carbon Nanocomposite for Overall Water Splitting in Alkaline Media
摘要： The development of designing and searching inexpensive electrocatalysts with highly activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is significant to enable water splitting as a future renewable energy source. Herein, we synthesis a new CoP(MoP)-CoMoO3 heterostructure coated by N-doped carbon shell (CoP(MoP)-CoMoO3@CN) via thermal decomposing and phosphatizing the CoMoO4?0.9H2O nanowires encapsulated in N-doped carbon. At 10 mA?cm?2, this CoP(MoP)-CoMoO3@CN nanocomposite exhibits superior electrocatalytic activity of low overpotentials of 296 mV for OER and 198 mV for HER in alkaline media. More importantly, we achieve a current density of 10 mA?cm?2 at 1.55 V by using this CoP(MoP)-CoMoO3@CN as both cathode and anode for overall water splitting. This promising performance could be due to the high activity of CoP(MoP)-CoMoO3 and the good conductivity of external mesoporous N-carbon shell, which makes the CoP(MoP)-CoMoO3@CN nanowires as a competitive alternative to noble metal based catalysts for water splitting.
关键词： metal phosphides,overall water splitting,synergistic effects,nanowires,N-doped Carbon
更新于2025-09-23 15:22:29
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On the Mechanism for the Extremely Efficient Sensitization of Yb3+ Luminescence in CsPbCl3 Nanocrystals
摘要： Rare earth (RE3+) doped inorganic CsPbX3 (X=Cl or Cl/Br) nanocrystals have been presented as promising materials for applications in solar-energy-conversion technology. An extremely efficient sensitization of Yb3+ luminescence in CsPbCl3 nanoparticles (NCs) was very recently demonstrated where quantum cutting is responsible for photoluminescence quantum yields over 100% (T. J. Milstein, et al., Nano Letters 2018, 18, 3792). In the present work, based on cubic phase of inorganic perovskite, we seek atom-level-insight into the basic mechanisms behind these observations in order to boost the further development of RE3+ doped CsPbX3 NCs for optoelectronics. In our calculations of cubic crystal structure, we do not find any energy level formed in the middle of the band gap, which disfavors a mechanism of step-wise energy transfer from the perovskite host to two Yb3+ ions. Our work indicates that the configuration with 'right-angle' Yb3+-VPb-Yb3+ couple are most likely to form in Yb3+-doped CsPbCl3. Associated with this 'right-angle' couple, the 'right-angle' Pb atom with trapped excited states would localize the photogenerated electrons and could act as the energy donor in a quantum cutting process, which achieves simultaneous sensitization of two neighboring Yb3+ ions.
关键词： Quantum cutting,Ytterbium-Doped inorganic perovskite,density function theory (DFT)
更新于2025-09-23 15:22:29
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Investigation of optical and electrical properties of lithium doped ZnO nano films
摘要： Investigation of undoped and lithium doped ZnO nano films deposited on glass substrates by sol-gel spin coating method have been carried out. The structural and morphological properties of the films with optimum post annealing temperature of 350°C have been investigated using X-ray Diffractometer (XRD) and Field emission scanning electron microscopy (FESEM) respectively. The XRD spectrum reveals that all the synthesised samples have single crystal structure having strong intense peak oriented along (002) c-axis. Crystalline size of undoped and Li doped ZnO nano films were deduced to be 34.66 nm and 32.59 nm respectively. FESEM exhibits uniform chromosome type structure. Nano films show transmittance above 90 % in the range of wavelength 350 nm to 800 nm. I-V characteristic shows linear and ohmic behaviour.
关键词： sol-gel,Li doped ZnO,Nano films
更新于2025-09-23 15:22:29
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Influence of thickness on the optical properties of Sb doped ZnO thin films
摘要： Sb doped ZnO thin films having various thicknesses have been prepared onto glass substrate by using thermal evaporation method. The atomic compositions of the grown films have been determined by Energy Dispersive Analysis of X-ray (EDAX) method. The optical properties were measured by using a UV-VIS-NIR spectrophotometer (300 to 2500 nm). The EDAX analysis revealed that Sb is doped into the ZnO films. Optical properties showed high absorption coefficient (~105/cm) that direct allowed transition band gap. The optical band gap of the ZnO thin films became reduced due to the doping of Sb.
关键词： Composition,Sb doped ZnO thin films,Optical properties,Thickness
更新于2025-09-23 15:22:29
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A novel Nd <sup>3+</sup> -doped MgO-Al <sub/>2</sub> O <sub/>3</sub> -SiO <sub/>2</sub> -based transparent glass-ceramics: towards excellent fluorescence properties
摘要： Generally, glass-ceramics have superior properties compared to their parent glasses. Here, we prepared a novel Nd3+-doped MgO-Al2O3-SiO2-based transparent glass-ceramics with excellent fluorescence properties. The effects of Nd2O3 content on the structure and properties of glass-ceramics were studied, aiming to provide a key guidance for preparing this transparent glass-ceramics. The results revealed that the glass stability increased originally and then decreased with increasing Nd2O3 content, so did the variation of wavenumbers in infrared spectra. And these glass-ceramics are mainly composed of cordierite with residual glassy phase. The three phenomenological intensity parameters (Ω2,4,6) and radiative properties were estimated by Judd-Ofelt theory, and the values of Ω2 first decreased and then increased with increasing Nd2O3 content. Three main emission peaks ascribed to the transitions from 4F3/2 to 4I9/2, 4I11/2, 4I13/2 at 898, 1057, 1330 nm were observed, respectively. The branching ratios for 4F3/2→4I11/2 transition increased as the Nd2O3 content raised, and the fluorescence lifetimes of the 4F3/2 level were found to increase first and then decrease with Nd2O3 content (from 181 to 726 μs). The excellent fluorescence properties indicate that this novel glass-ceramics can be used as a potential solid-state optical functional material for 1.06 μm laser emission.
关键词： MgO-Al2O3-SiO2,Judd-Ofelt theory,Nd3+-doped,Transparent glass-ceramics,Solid-state optical functional materials
更新于2025-09-23 15:22:29
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Nonlinear multimodal interference for ytterbium-doped all-fiber mode-locking noise-like pulse generation
摘要： This work demonstrates the generation of the noise-like pulse (NLP) in an all-normal-dispersion passively mode-locked ytterbium-doped ring laser cavity with nonlinear multimodal interference as an equivalent all-fiber saturable absorber, for the first time to the best of our knowledge. Depending on the appropriate optimization of the intra-cavity birefringence and reasonable control of the curving curvature of the multimode fiber, self-started NLP operation can be built and maintained within a wide pump range. Additionally, the effect of the multimode fiber length on the NLP mode-locking performance and the generation of the high power NLP have also been experimentally studied.
关键词： ytterbium-doped fiber,all-fiber laser,nonlinear multimodal interference,noise-like pulse,mode-locking
更新于2025-09-23 15:22:29