ACS Sustainable Chemistry & Engineering
·
2022
·
IF 9.224
Lin Yang,Hao Wu,Guo-hui Pan,Liangliang Zhang,Huajun Wu,Zhendong Hao,Feng Liu,Jiahua Zhang
The luminescence thermal enhancement (LTE), in lanthanide-doped upconverting nanocrystals (UCNCs), has attracted extensive attention for its applications in anticounterfeiting, temperature sensing, and so on. Some mechanisms for LTE were proposed, including thermally induced water desorption from the surface of UCNCs, but conclusive evidence is absent for any of the mechanisms. Here, vacuumizing is employed in the experiment for the LTE in NaYF4:Ho3+/Yb3+ UCNCs, and significantly promoted LTE is observed. The 300–450–300 K temperature cycling experiment in vacuum shows continuous luminescence enhancement without luminescence intensity recovery as in the cooling process in moisture air, indicating the effect of water desorption because water readsorption is blocked in vacuum. It is found that the Ho3+ 5I6 level can be deexcited by direct long-range energy transfer to water adsorbed at the surface of nanocrystals due to resonant coupling between the Ho3+ 5I6 → 5I7 transition and the −OH vibration of water. As a result, water desorption suppresses the 5I6 depopulation and thus enhances the luminescence of Ho3+. Finally, the regulation of upconversion LTE is realized by adjusting the size of nanocrystals and Ho3+ or Yb3+ concentrations. Our findings indicate that the vacuumizing technique is an effective method to distinguish water-desorption-induced LTE. This work deepens the understanding of LTE and offers insights into the regulation of LTE.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2019
·Vol. 24
·期 2
·
IF 3.06
Lili Xu,Man Wang,Qing Chen,Jiajia Yang,Wubin Zheng,Guanglei Lv,Zewei Quan,Chunxia Li
In recent years, rare earth doped upconversion nanocrystals have been widely used in different fields owing to their unique merits. Although rare earth chlorides and trifluoroacetates are commonly used precursors for the synthesis of nanocrystals, they have certain disadvantages. For example, rare earth chlorides are expensive and rare earth trifluoroacetates produce toxic gases during the reaction. To overcome these drawbacks, we use the less expensive rare earth hydroxide as a precursor to synthesize β-NaYF4nanoparticles with multiform shapes and sizes. Small-sized nanocrystals (15 nm) can be obtained by precisely controlling the synthesis conditions. Compared with the previous methods, the current method is more facile and has lower cost. In addition, the defects of the nanocrystal surface are reduced through constructing core–shell structures, resulting in enhanced upconversion luminescence intensity.
✓ 已验证
DOI
高影响因子
SOLAR ENERGY
·
2020
·
IF 4.608
Hanyu Yao,Quntao Tang
To improve energy conversion efficiency ( E ff ) of silicon solar cells, luminescent down-conversion (DC) is an effective approach to adjust solar spectrum by converting ultraviolet light to visible and near-infrared light. In this paper, Tb 3+ - Yb 3+ co-doped NaYF 4 phosphors (DCNPs) were successfully synthesized by a simple solvothermal method. It was confirmed from the strong photoluminescence excitation (PLE) and photoluminescence (PL) emission peaks that the energy transfer occured between Tb 3+ and Yb 3+ ions. The DCNPs were added in the SiO 2 sol-gel to prepare anti-reflection coatings with DC performance, enhancing the visible and near-infrared region transmittance which matched with the band gap of silicon. An optimized short-circuit current density ( J sc ) of 33.39 mA/cm 2 and a relatively enhanced E ff of 6.74% were achieved in the silicon solar cells with the bi-functional film. These results indicated the availability of anti-reflection coating with DCNPs for improving energy conversion efficiency of silicon solar cells.
研究领域:
光伏技术
·
材料科学
·
纳米技术
·
光学涂层
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Shaokun Ling,Xiaoyan Qin,Chang chen,Kai Meng,Yifeng Yan,Junyun Ming,Sen Liao,Yingheng Huang,Lei Hou
Despite long-term development of LEDs, problems urgent to resolve is still existing. The most outstanding problem to tackle is luminescent stability at high temperature working situation. In this study, a novel type of β-NaYF 4 based phosphor incorporated with Eu 3+ and Tb 3+ is reported. A series of β-NaYF 4 :0.065Eu 3+ , x Tb 3+ ( x = 0.001, 0.002, 0.003, 0.004, 0.005) phosphors were synthesized by hydrothermal method . The sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ possesses optimal luminescent property at room temperature. The mechanism of energy transfer from Tb 3+ to Eu 3+ ion is quadrupole-quadrupole interactions. The sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ demonstrates zero thermal quenching (ZTQ) property at 303 K to 383 K. According to XRD and XPS characterizations, nonequivalent replacement between intrinsic ion Na + and Y 3+ were discovered, which finally leads to production of crystal defects. According to electron paramagnetic resonance (EPR) characterization and density functional theory (DFT) calculation, the type of crystal defect of β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ is confirmed to be V Y vacancies which are the predominant defect of crystal. The depths and densities of defects were calculated according to data of thermoluminescence spectra (TL spectra). Crystal defects play the role of electrons traps that could store electrons. Electrons stored in traps will be excited to excitation state of Eu 3+ under the thermal stimulation to offset undesirable impact of thermal quenching (TQ), which leads to ZTQ property of the sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ . The CRI and CCT of fabricated WLED are 3830 K and 84.1, respectively.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 42
·15897-15905
·
IF 8.067
Hanchang Huang,Maohui Yuan,Zhongyang Xing,Wenda Cui,Tongcheng Yu,Shuai Hu,Guomin Zhao,Chuan Guo,Kai Han
In lanthanide-sensitized upconversion (UC) nanomaterials, the typical sensitizer Yb3+ can significantly modulate the codoped activator (such as Er3+ ions) to generate multiband transitions. However, the kinetics of these multiband emissions affected by the Yb3+ concentration remains unclear. In this work, we employ nanosecond time-resolved spectroscopy to investigate a single optically trapped NaYF4:Yb/Er microcrystal (MC) doped with different Yb3+ concentrations. Interestingly, high doping Yb3+ ions shorten the UC response time by a factor of 10 (from ∼1 μs to ∼100 ns) compared to low doping Yb3+. Meanwhile, 430 nm light (4G7/2 → 4I11/2) emitted before 654 nm (4F9/2 → 4I15/2) with Yb3+ dramatically increasing (opposite to the normal low Yb3+ doping cases), representing a new four-photon pathway (4I15/2 → 4I11/2 → 4F7/2 → 2H11/2 →4S3/2 → 2G7/2 → 4G11/2 → 2H9/2 → 2D5/2 → 4G7/2). Furthermore, we observed a broad range of time-dependent emission color, changing from being initially green over near-white to red. Particularly, the red emission is dominated in the decay process, yielding insight into the fundamental multiband UC kinetics. The result shows that varying the Yb3+ doping concentration provides a way to control the energy flow between the energy levels of Er3+ ions, which can modulate the response time and color evolution of UC on Yb/Er doped materials. This can direct the prospective development of fast-response optoelectronic devices, photocatalysis, and UC displays in the future.
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2022
·
IF 3.754
Xiaomin Ning,Na Liu,Jinyang Liu,Yue Wu,Jing Qian,Wenchao Zhang,Wen Gu
The practical application of light thermometer based on the FIR (520/540) has been greatly limited due to the strong absorption of green light by biological tissues. The sensitivity of the temperature sensor located in a biological window (FIR-BW) also needs to be improved. Based on this, we designed and synthesized an upconversion nanoparticles (UCNPs) with suitable R/G ratio and red visual output to prebreaking the limitation of strong absorption of biological tissue, while improving the sensitivity of temperature sensor and in vivo fluorescence imaging. In this paper, NaErF 4 :40%Tm@NaYF 4 , a high efficient red UCNPs with R/G ratio (6.86), is first utilized as an optical thermometer, accomplished through the fluorescence intensity ratio (FIR) of thermally coupled stark sublevels of 4 S 3/2 / 4 F 9/2 (FIR(540/654)). In the studied temperature range, the maximum absolute and relative sensitivity (S a and S r ) is 0.47% K −1 and 2.61% K −1 at 298 K, respectively, which is much higher than most previous reports about FIR-based temperature sensors. Additionally, we investigated the in vivo bioimaging behavior of NaErF 4 :40%Tm@NaYF 4 in detail. The superior biocompatibility, the distribution to the main organs with the blood circulation system, and the bright red fluorescence signals were observed under 980 nm laser radiation . All the results imply that NaErF 4 :40%Tm@NaYF 4 is a promising candidate for optical thermometry and in vivo bioimaging with high sensitivity.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2021
·
IF 6.789
Ying Zhang,Yujie Luo,Shiqi Fu,Xiulong Lv,Qian He,Fangying Ji,Xuan Xu
UVC (wavelength < 280 nm) has a wide range of applications in the field of water disinfection due to its excellent bactericidal performance. In this work, we synthesized an upconversion luminescent material, β-NaYF 4 : Pr 3+ , Li + (NYF), which can generate UVC, and compounded it with a BiOCl photocatalyst to synthesize β-NaYF 4 : Pr 3+ , Li + @BiOCl (NYF-Bi) with a core-shell structure. The NYF-Bi composite material can be driven under visible light and has high photocatalytic activity . The bactericidal performance of NYF and NYF-Bi were evaluated using Escherichia coli , Staphylococcus aureus , Shigella and Salmonella . The NYF-Bi composite material killed 99.99% of E. coli under visible light (λ ≥ 420 nm) within 180 min and maintained high germicidal efficacy after 4 cycles. Finally, we deduced the sterilization mechanism of the NYF-Bi composite material through carrier dynamics studies and catching agent experiments. The death of bacteria was mainly caused by UVC light and active species , including h + , OH, and O- 2. This research provides a new material for water disinfection.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 48
·15269-15275
·
IF 6.641
Hui Zhang,Jiatao Ye,Xiuli Wang,Shilong Zhao,Ruoshan Lei,Lihui Huang,Shiqing Xu
Accurate and remote temperature measurements in harsh environments are of great importance. The FIR technique is self-referenced and regarded as a promising method to improve the temperature accuracy and simplify the experimental devices. Herein, a point all-fiber temperature sensor based on the FIR technique has been developed. Er3+/Yb3+ co-doped NaYF4 phosphors (NPs) were used to fabricate a temperature sensing probe combined with silica fiber. Highly crystalline and pure hexagonal NPs were synthesized by a hydrothermal method. Intense green up-conversion luminescence was observed in the prototype sensor at an excitation power of 1 mW. The relationship between FIR value and temperature was investigated at the temperature range of 258–423 K. The maximum relative temperature sensitivity is 1.68% K−1 at 258 K. Preliminary experimental results indicate that the absolute error is ±1 K with a temperature uncertainty σ of 0.187 K and relative standard deviation of 0.133%, suggesting the high accuracy and reliability of the proposed all-fiber temperature sensor.
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 21
·6917
·
IF 3.4
Qi Luo,Jian Yu,Xueshuang Deng,Ming Cao,Shifang Ma,Qiongxin Hua,Dan Xue,Fenghui An
In this study, we aim to minimize light loss and achieve high power conversion efficiencies (PCE) in perovskite solar cells (PSCs) by employing a spectral conversion film component with antireflection properties. In our scheme, NaYF4:Tm, Yb, and Gd luminescent nanorod/silica nanosphere-based thin films are applied on CH3NH3PbI3PSCs to improve the device efficiency. The film was fabricated by spin coating an aged silica sol containing NaYF4:Tm, Yb, and Gd luminescent nanorods. The size and the spectral conversion properties of the NaYF4:Tm, Yb, and Gd luminescent nanorods were controlled by tuning the Gd3+ion concentration. The microstructure and the transmittance properties of the thin film were controlled by changing the concentration of NaYF4:Tm, Yb, and Gd luminescent nanorod in silica sol. The thin films have excellent spectral conversion properties while exhibiting a maximum transmittance. The photovoltaic performance of PSCs with NaYF4:Tm, Yb, and Gd luminescent nanorod/silica nanosphere-based thin films was systematically investigated. The light transmittance was optimized to 95.1% on a cleaned glass substrate, which resulted in an average increase of about 3.0% across the broadband range of 400–800 nm. The optimized films widen the spectrum of light absorbed by conventional PSC cells and reduce reflections across a broad range, enhancing the photovoltaic performance of PSCs. As a result, the PCE of the PSC increased from 14.51% for the reference device without a thin film to 15.67% for the PSC device with an optimized thin film. This study presents a comprehensive solution to the problem of Fresnel reflection and spectral response mismatch of the PSCs, which provides new ideas for the light management of PSCs.Keywords:perovskite solar cells;spectral conversion;NaYF4;antireflection coating;SiO2
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Tao Pang,Mingyue Cai,Qiqi Chen,Jianping Xie,Ronghua Jian,Wenhui Lu
NaYF 4 :Yb 3+ /Ho 3+ /Ce 3+ upconversion phosphors were synthesized by using a citric acid assisted hydrothermal method . Both increasing the concentration of Ce 3+ and decreasing the Yb 3+ content are beneficial to the formation of cubic NaYF 4 . When the concentration of Yb 3+ /Ho 3+ /Ce 3+ were 20/1/20 and 5/1/10, respectively, a pure cubic phase was obtained. The spectral conversion from green to red was achieved by first increasing Ce 3+ concentration to 10% and then decreasing the Yb 3+ concentration to 5%. In the first half, the two cross relaxation processes between Ho 3+ and Ce 3+ were responsible for the modulation of the luminescence, while in the latter half, the enhanced intensity ratio of red to green emission was related to the decreased energy transfer from Ho 3+ to Yb 3+ . Except for the sample doped with 5% Yb 3+ , 1% Ho 3+ and 10% Ce 3+ , the total emission intensity of other samples decreased linearly with increasing sample temperature. The maximum responsibility was obtained in the case of 20% Yb 3+ , 1% Ho 3+ and 5% Ce 3+ doping. Compared to the Er 3+ based luminescent temperature sensing, this novel temperature sensing not only shown little impact from pump power, but also had the identical sensitivity at various temperatures, and thus being a promising candidate for temperature sensing.
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale Horizons
·
2018
·Vol. 3
·期 6
·616-623
·
IF 9.391
Baoqi Liu,Zhipeng Meng,Suli Wu,Yue Wu,Shufen Zhang
Rational control of the multiple emission outputs and achieving single-band and strong luminescence of Ln3+ doped upconversion nanoparticles is highly desirable for their applications in sensor and display fields. Here, we designed a sandwich structure to separate and enhance the green and red emission of NaYF4:Yb3+/Er3+ simultaneously and realized pure strong green and red emissions. NaYF4:Yb3+/Er3+ nanocrystals were sandwiched between two layers of photonic crystals, which have bandgaps at 660 nm and 530 nm, respectively. The photonic crystal with a bandgap at 530 nm on top of the NaYF4:Yb3+/Er3+ layer can filter the green emission of NaYF4:Yb3+/Er3+, prohibiting its emission upward, and at the same time, enhancing its emission downward. Similarly, the photonic crystal with a bandgap at 660 nm can prohibit the transmission of the red emission, and at the same time enhance its reflection in the opposite direction. Consequently, enhanced green emission was observed from the bottom of the sandwich structure and enhanced red emission was observed from the top of the sandwich structure. Thus, the green and red emissions of NaYF4:Yb3+/Er3+ were separated and both of them were enhanced. On the other hand, when using a photonic crystal with a bandgap that overlapped with the excitation light of NaYF4:Yb3+/Er3+ nanoparticles, their emissions were all greatly enhanced. Our results suggest that photonic crystals are good candidates to separate and enhance the emissions of Ln3+ doped luminescent materials.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYST
·
2018
·Vol. 143
·期 17
·4199-4205
·
IF 3.864
Jinzha Zhang,Yang Shen,Yuhong Liu,Zaiying Hou,Yuanqing Gu,Wenbo Zhao
A novel electrochemiluminescence (ECL) cytosensor was proposed for the quantitative detection of HeLa cells (human cervical cancer cells) with the help of a signal amplification strategy. Firstly, the Au-NaYF4:Yb,Er nanocomposites were prepared by a simple in situ hydrothermal method and characterized by transmission electron microscopy (TEM) images, X-ray diffraction (XRD) patterns, UV-vis spectra and Fourier transform infrared (FTIR) spectra. Compared with the bare NaYF4:Yb,Er nanocomposites, the ECL intensity of Au-NaYF4:Yb,Er nanocomposites was greatly enhanced by about 4.2-fold which can be attributed to the good conductivity of gold nanoparticles (Au NPs). The nanocomposites showed high and stable ECL emission, fast response and superior conductivity, all of which were advantageous to the ECL detection. Furthermore, HeLa cells were immobilized on the modified electrode via the interaction between folic acid and a folate receptor present on the cell surface. The ECL cytosensor showed satisfactory sensitive response to HeLa cells in a linear range of 4.25 × 102–4.25 × 105 cells per mL with a low detection limit of 326 cells per mL. The proposed cytosensor had good sensitivity and stability, which can offer a great potential platform for bioassay analysis.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）