PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION
·
2020
·Vol. 37
·期 2
·1900445
·
IF 3.099
Artem Yakovliev,Tymish Y. Ohulchanskyy,Roman Ziniuk,Tereza Dias,Xin Wang,Hao Xu,Guanying Chen,Junle Qu,Anderson S. L. Gomes
In this work, the application of near infrared (NIR)-emitting NaYbF 4 :1%Tm 3+ @NaLuF 4 :30%Nd 3+ core–shell nanoparticles is reported for noninvasive probing and monitoring the temperature during photopolymerization of dental materials. When excited at 808 nm, the synthesized nanoparticles emit NIR photoluminescence (PL) with two distinctive peaks at 865 and 980 nm which correspond to radiative transitions from the doped Nd 3+ and Yb 3+ ions, respectively. Luminescence intensity ratio between these two bands is found to vary with temperature due to temperature-dependent electronic excitation energy transfer between Nd 3+ and Yb 3+ ions at the core/shell interface. This finding allows luminescence ratiometric evaluation of the in situ temperature during photopolymerization of resin cement (doped with nanoparticles) in a veneer placement procedure. In addition, the NIR emission also enables PL imaging of the distribution of the adhesive under the veneer. The results highlight that rare-earth ions–doped nanoparticles with both excitation and emission in the NIR spectral range are advantageous for both PL-based nanothermometry and imaging due to the reduced attenuation of NIR light by dental ceramics.
研究领域:
生物医学工程
·
牙体牙髓病学
·
纳米医学
·
光学成像
·
生物材料
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2014
·Vol. 39
·期 9
·4198-4205
·
IF 2.93
Zhenlong Zhang,Jichun Zhu,Shengjun Li,Xiangyang Liu,Yanli Mao
In this paper, TiO 2 nanotube (TNT) arrays and (Cu 2 Sn) x /3 Zn 1− x S ( x = 0.75, 0.24, and 0.09) nanocrystals were prepared, and TiO 2 nanotubes (TNTs) were sensitized with (Cu 2 Sn) x /3 Zn 1− x S nanocrystals. Compared with the plain TNTs, (Cu 2 Sn) x /3 Zn 1− x S sensitized TNTs present an enhanced photoelectrochemical response. The photocurrent enhancement was characterized with the photocurrent ratio of (Cu 2 Sn) x /3 Zn 1− x S sensitized TNTs to plain TNTs, which were 1.50, 1.63, and 2.13 for (Cu 2 Sn) x /3 Zn 1− x S with the composition of x = 0.75, 0.24, and 0.09, respectively. To understand this phenomenon, the energy band alignments of TNTs and (Cu 2 Sn) x /3 Zn 1− x S were investigated, based on which the conduction band offsets (CBO) between TNTs and (Cu 2 Sn) x /3 Zn 1− x S were determined, which were 0.31, 0.47, and 0.63 eV for (Cu 2 Sn) x /3 Zn 1− x S with the composition of x = 0.75, 0.24, and 0.09, respectively. These results display that the photocurrent enhancement becomes large with the increase of CBO, which indicates that the enhanced photoelectrochemical response is mainly due to the energy level matching between TNTs and (Cu 2 Sn) x /3 Zn 1− x S, and the variation of enhancement is resulting from the change of CBO.
研究领域:
材料科学
·
光催化
·
半导体纳米材料
·
能源材料
·
光电化学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 26
·8697-8705
·
IF 4.099
Yang Ding,Jie Liu,Ming Zeng,Xishu Wang,Junli Shi,Weili Wang,Yanru Miao,Xibin Yu
Rare earth (RE3+)-doped NaY(MoO4)2 nanocrystals are efficient materials for realizing multicolor emission, which plays an important role in displays, W-LEDs, solar cells and biolabeling. Up to now, research on the multicolor tuning properties of RE3+-doped NaY(MoO4)2 nanoparticles has mostly focused on traditional preparation routes such as the hydrothermal method and sol–gel process. However, the products obtained using these methods are usually large in size (on the micron/submicron scale) and agglomeration problems are inevitable. With the development of nano optoelectronic devices and bioluminescence labeling, there is an urgent need to find an efficient method to prepare nanoscale, monodispersed and NaY(MoO4)2:RE3+ nanocrystals (NCs) with good crystallinity and stronger emission properties. In this work, we demonstrate a simple, fast, reproducible and one-step synthesis of NaY(MoO4)2:Eu3+ NCs with sizes varying from 1–20 nm via a ligand-assisted reprecipitation strategy. The reaction mechanism and emission intensities of NaY(MoO4)2:Eu3+ NCs with various morphologies have been discussed in detail. Furthermore, Tb3+ and Eu3+ ion co-doped NaY(MoO4)2 NCs were also prepared, and various emission colors were obtained and tuned from red, orange-red, yellow and yellow-green to green. Energy transfer between the Tb3+ and Eu3+ ions in the NaY(MoO4)2 host matrix has also been demonstrated. Finally, a highly efficient and stable NaY(MoO4)2:0.05Tb,0.04Eu NC-based W-LED device was built, which indicates the promising future application for this material in the field of lighting. The tunable multicolour emission, ease of preparation and nanosize reveal that NaY(MoO4)2:RE3+ NCs have a potential application in full color displays and W-LEDs.
研究领域:
材料科学
·
纳米技术
·
光学材料
·
无机化学
·
光电子学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS RESEARCH
·
2014
·Vol. 29
·期 20
·2473-2482
·
IF 1.815
Yingchang Ke,Hongxu Guo,Dongfang Wang,Jianhua Chen,Wen Weng
The ZrO2 and graphitic carbon nitride (g-C3N4) composite photocatalyst has been prepared by calcination process and hydrothermal treatment. The photocatalyst was characterized by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, UV–vis diffuse reflection spectroscopy, Brunauer–Emmett–Teller and photoluminescence spectra. The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue under visible light irradiation. The results showed that the activity of the composite photocatalyst ZrO2/g-C3N4 for photodegradation of MB is much higher than that of either pure g-C3N4 or ZrO2, which is ascribed to the effective electron–hole separation based on the photoluminescence spectra. The •O2 − might be the main active species in MB photodegradation, and the •OH and photogenerated electrons are also partly involved in the process of photocatalytic degradation.
研究领域:
材料科学
·
环境化学
·
光催化
·
纳米材料
·
表面科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 7
·5944-5953
·
IF 2.324
Gao Huhu,Mo Zunli,Guo Ruibin,Niu Xiaohui,Li Zhenliang
Photocatalytic efficiency of CdS can be improved significantly by controlling the morphology and recombining with other semiconductor materials. In this work, a novel snowflake-like CdS/reduced graphene oxide (rGO) composite was prepared by a simple hydrothermal process using graphene oxide and CdS as raw materials and l -aspartic acid as template. The structure of the composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction. Through a basic analysis, a simple synthesis mechanism of snowflake-like CdS is proposed, and transient photocurrent technology demonstrate that the photocurrent of snowflake-like CdS/rGO is greatly improved. Compared with pure CdS, snowflake-like CdS/rGO exhibits efficient organic dye adsorption and degradation under visible light irradiation, resulting from the involving of rGO sheet as chainmail, which facilitates the charge separation, suppresses the recombination of electron–hole pairs, and improves light conversion efficiency of catalysts.
研究领域:
材料科学
·
环境化学
·
纳米科技
·
光催化
·
复合材料
·
半导体材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Ganggang Guo,Qiong Xi,Tao Yin,Jianju Nie,Yayuan Zhang,Li Guan,Zhenyang Liu,Fenghe Wang,Xu Li
Broadband near-infrared (NIR) phosphors are key materials for the preparation of NIR phosphor-converted light-emitting diodes (pc-LEDs). The wider coverage of the NIR spectrum means that more substances can be detected by NIR light and more applications are possible. However, ultra-broadband NIR phosphors with the full-width at half maximum (FWHM) greater than 200 nm still face challenges in terms of thermal stability as well as internal quantum efficiency (IQE). In this work, a series of La 2 CaTa x Zr (1- x ) O 6 (LCTZO): Cr 3+ phosphors was successfully synthesized by the high-temperature solid-phase method. The non-equivalent substitution strategy of Ta 5+ in place of Zr 4+ effectively modulates the crystal field environment of Cr 3+ and reduces the number of defects, thus modulating the luminescence properties of the phosphor. Under the 471 nm excitation, the spectrum of La 2 CaTa 0.3 Zr 0.7 O 6 : 2 % Cr 3+ can cover the 700–1400 nm band (FWHM = 201 nm) with IQE of 42.6 %, and the emission intensity can be maintained at 373 K at 74 % of that at room temperature . The prepared NIR pc-LED with ultra-wide spectral coverage shows better potential applications in the fields of night vision and biological tissue penetration.
研究领域:
材料科学
·
光学工程
·
生物医学工程
·
分子成像
·
光电子学
·
纳米医学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Yanzhen Yin,Wenhua Yang,Zhen Wang,Yue Zhang,Maochen Zhu,Chao Dou,Yang Che,Shijia Sun,Chen Hu,Bing Teng,Jiaqi Zhao,Jingyao Lu,Ruyi Sun,Degao Zhong
The struggle with "thermal load" is always an unavoidable challenge for photo-luminescent material. In this work, a novel red phosphor of ZnGa 2 O 4 : Eu 3+ with spinel-type structure is prepared by high-temperature solid-phase method. Due to the charge imbalance during the replacement processes of Ga 3+ →Zn 2+ and Eu 3+ →Zn 2+ in mixed spinel structure, vacancy defects can be introduced into the lattice structure of ZnGa 2 O 4 : 0.02Eu 3+ . The results of Density Function Theory (DFT) calculation demonstrate that the existence of vacancy defects can construct defect energy levels in the energy band structure of the host crystal, which can assist enhancing the fluorescence emission intensity of the phosphor at high temperature. The strong thermal stability of its own structure combined with the assistance of defect energy levels enables the achievement of zero-thermal quenching in ZnGa 2 O 4 : 0.02Eu 3+ under multi-wavelength excitation. Our results open up a new way for the exploration and utilization of zero-thermal quenching phosphors.
研究领域:
材料科学
·
发光材料
·
固态化学
·
计算材料学
·
无机功能材料
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Meilin Lv,Gang Liu,Xiaoxiang Xu
Strong visible light absorption and high charge mobility are desirable properties for an efficient photocatalyst, yet they are hard to be realized simultaneously in a single semiconductor compound. In this work, we demonstrate that these properties coexist in homologous compounds ZnnIn2O3+n (n = 4, 5, and 7) with a peculiar layered structure that combines optical active segment and electrical conductive segment together. Their enhanced visible light absorption originates from tetrahedrally or trigonal-bipyramidally coordinated In atoms in Zn(In)O4(5) layers which enable p–d hybridization between In 4d and O 2p orbitals so that valence band minimum (VBM) is uplifted with a reduced band gap. Theoretical calculations reveal their anisotropic features in charge transport and functionality of different constituent segments, i.e., Zn(In)O4(5) layers and InO6 layers as being for charge generation and charge collection, respectively. Efficient photocatalytic hydrogen evolution was observed in these compounds under full range (λ ≥ 250 nm) and visible light irradiation (λ ≥ 420 nm). High apparent quantum efficiency ∼2.79% was achieved for Zn4In2O7 under full range irradiation, which is almost 5-fold higher than their parent oxides ZnO and In2O3. Such superior photocatalytic activities of these homologous compounds can be understood as layer-by-layer packing of charge generation/collection functional groups that ensures efficient photocatalytic reactions.
研究领域:
材料化学
·
光催化
·
半导体物理
·
能源材料
·
无机化学
·
表面科学
✓ 已验证
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2018
·Vol. 124
·期 10
·1-8
·
IF 1.604
Mo Xi,Hu Jiamin,Shen Hui,Shui Lingling,Shu Dong,He Junfeng,He Guannan,Wang Yinzhen,Li Wei,He Qinyu
In photocatalyst design, the rapid recombination of photo-generated electron–hole pairs in the bulk or on the surface of semiconductors is a major limiting factor in achieving high photocatalytic efficiency, which is a key scientific issue. Surface modification is used to change the surface properties of photocatalyst related to dark adsorption and photocatalytic efficiency. In this work, micro-sized CuO powder was surface modified by in situ-growing heterojunctions CuO/Cu 2 O and CuO/Cu 2 O/Cu when simply calcinating a mixture of CuO and urea, in which urea acted as a reducing agent. The phases, microstructure, composition, photogenerated carrier lifetime, dark adsorption rate, photodegradation rate, and surface charges of the as-modified powder were investigated. The surface modification was found to change the negative surface charge of micro-sized CuO to a positive one, resulting in enhanced dark adsorption (nearly twice that of pristine CuO). Furthermore, the surface modification prolonged the photogenerated carrier lifetime, which in turn enhanced the photocatalytic efficiency. Overall, this work implies that the electric properties of surface charges and carrier lifetime can be altered by constructing an appropriate heterojunction on the surface of the photocatalyst.
研究领域:
材料科学
·
光催化
·
表面化学
·
半导体物理
·
环境功能材料
·
纳米科技
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2020
·
IF 5.627
Zeyun Wu,Yiyang Zhang,Xiaofan Zhao,Hongyan Wang,Shuiqing Li
Yttrium aluminum oxide YAlO 3 is an attractive laser host material for lanthanide ions like Nd 3+ . In this paper, a dual liquid/vapor-fed flame synthesis (DLVF) system is developed for investigating the role of SiO 2 coating on flame-made YAlO 3 :Nd 3+ nanophosphors. The hexamethyldisiloxane (HDMSO) vapor is flexibly fed into the YAlO 3 :Nd 3+ flame spray flow at different positions and molar ratios . We find that the introduction of SiO 2 coating dramatically improves the crystallinity of YAlO 3 :Nd 3+ cores because of the heat-insulation effect and nearly doubles the fluorescence intensity . Through a timescale analysis, we demonstrate that the best timing for coating injection is when the small particles have already been formed but not heavily aggregated. An early injection could result in segregated SiO 2 particles and some impurities like Al 2 SiO 5 , while a delayed injection leads to the coating of SiO 2 on the entire aggregates instead of on individual particles. Experiments of different coating ratios show that the coating ratio 1:1 of Si:(Y+Nd) produces the best crystallinity and strongest fluorescence intensity. Further increase of the coating ratio does not show any improvements of the crystallinity , and may even causes the decrease of the relative fraction of Nd 3+ ions. Compared with YAG:Nd 3+ bulk materials (with a typical optimum doping concentration 1.1mol%) and uncoated YAlO 3 :Nd 3+ nanophosphors (with an optimum doping concentration 2 mol%), the SiO 2 coating promotes the optimum Nd 3+ doping concentration up to 3 mol%.
研究领域:
材料科学
·
无机化学
·
纳米技术
·
发光材料
·
激光增益介质
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS CHEMISTRY
·
2012
·Vol. 22
·期 11
·4847-4854
·
IF 5.968
Desong Wang,Yandong Duan,Qingzhi Luo,Xueyan Li,Jing An,Leilei Bao,Lei Shi
A new method for the preparation of mesoporous TiO2 with a surface deposited with nanoparticles of Ag and AgBr was developed. Cetyltrimethylammonium bromide (CTAB) was used as both a template agent and bromine source in the preparation process of the mesoporous TiO2. Mesoporous TiO2 containing CTAB was synthesized by a sol–gel method, and was dipped into AgNO3 solution to form a mesoporous AgBr/TiO2 nanocomposite. The AgBr/TiO2 nanocomposite was irradiated by visible light to accelerate photolysis of AgBr, forming mesoporous Ag/AgBr/TiO2 photocatalyst. The Ag/AgBr/TiO2 photocatalyst was characterized by small angle X-ray diffraction (SAXRD), wide angle X-ray diffraction (WAXRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and N2 isothermal adsorption–desorption. Ag/AgBr/TiO2 exhibits high photocatalytic activity for the degradation of methyl orange under visible light irradiation. The photocatalytic reaction follows the first-order kinetics and the rate constant (k) for the degradation of methyl orange photocatalyzed by Ag/AgBr/TiO2 is 63.6, 36.1 and 2.7 times that of mesoporous TiO2 (M-TiO2), commercial TiO2 (P-25), and Ag/AgBr/SiO2, respectively. The recycling runs experiment shows that the photocatalytic stability of the Ag/AgBr/TiO2 photocatalyst is excellent. The visible light photocatalytic mechanism of Ag/AgBr/TiO2 is also discussed.
研究领域:
材料科学
·
光催化化学
·
纳米材料
·
环境功能材料
·
表面科学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2016
·
IF 6.333
Ya-Ping Que,Jian Weng,Lin-Hua Hu,Ji-Huai Wu,Song-Yuan Dai
The morphology, microstructure and crystallography of titanium dioxide (TiO 2 ) have great effect on the photoelectric performance of dye-sensitized solar cells (DSSCs). Herein, flower-like 3D TiO 2 microstructures based on well-defined high-crystalline nanosheets are synthesized through a facile hydrothermal method . Especially, morphological evolution process and mechanism of this hierarchical structure are investigated. Due to the highly crystalline nature and smaller surface area of these nanosheets , the corresponding device shows an extremely high open-current voltage up to 0.84 V, which results from the less electron recombination. When applied as a scattering layer on top of the nanoparticle layer, the power conversion efficiency (PCE) can be significantly improved and give birth to a PCE value of 9.6%, which is 24.6% higher than that of an analogous device using nanoparticles (NP) (7.7%). As reflected by diffusion reflection spectra, intensity of the modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) and electrochemical impedance spectra (EIS), this hierarchical structure can not only enhance light harvesting, but also reduce electron recombination, facilitate electron transport and improve electron collection efficiency.
研究领域:
材料科学
·
纳米科技
·
能源化学
·
光伏技术
·
半导体物理
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）