Journal of Materials Chemistry C
·
2014
·Vol. 2
·期 41
·8811-8816
·
IF 0
E. H. Song,J. L. Wang,D. C. Yu,S. Ye,Q. Y. Zhang
In contrast to common visible emission, an anomalous near-infrared (NIR) emission band at 790 nm has been demonstrated in the spinel structure MgGa2O4:Mn2+ with heavy Mn2+ doping. Tunable single-band visible to visible-NIR and single-band NIR emission are easily realised upon tuning the doping concentration of Mn2+. Careful investigation of the crystal structure, fluorescence lifetime and excitation & emission spectra indicates that the NIR emission might be ascribed to the 6A1(6S)4T1(4G) → 6A1(6S)6A1(6S) transitions of Mn2+–Mn2+ dimers. When some Yb3+ ions are codoped into the spinel MgGa2O4:Mn2+, room temperature visible upconversion (UC) emission is realised upon excitation with a 976 nm laser diode. The temperature-dependent UC emission properties as well as the related UC mechanism have been investigated. Understanding the nature of the Mn2+ Stokes and UC emissions is the key to developing advanced photonic devices with improved properties and manufacturability for engineering applications.
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SOLAR ENERGY
·
2019
·
IF 4.674
Wanxian Cai,Zhaobin Zhang,Yuanzeng Jin,Yanqi Lv,Ling Wang,Koucheng Chen,Xingfu Zhou
In this work, the up-conversion phosphor NaYF 4 :Yb 3+ , Er 3+ nanocrystalline mixed with P 25 and TiO 2 hollow microspheres with high light scattering ability were fabricated as electrode for dye-sensitized solar cells (DSSCs). Meanwhile, we take advantage of the low cost feature of the carbon counter electrode to replace the precious metal Platinum (Pt) of DSSCs. SEM results show that the well-dispersed TiO 2 hollow microspheres size is 1.5 μm with surface consisting of a large number of rice-like nanorods. The particle size of the as-prepared NaYF 4 :Yb 3+ , Er 3+ nanoparticles is about 80 nm. The Photocurrent-Voltage curve of P 25 /NaYF 4 :Yb 3+ , Er 3+ cell under 980 nm infrared light has an obvious infrared photoresponse. The fabricated DSSCs using NaYF 4 :Yb 3+ , Er 3+ achieves power conversion efficiency (PCE) of 5.27% under one sun illumination, which shows an increase of 16% when compared with the benchmark P 25 cell (4.55%). In addition, the optimized DSSC using TiO 2 hollow microspheres as the top scattering layers with NaYF 4 :Yb 3+ , Er 3+ /P 25 exhibits a prominent PCE of 6.23%, which shows a 37% increase in conversion efficiency when compared with the commercial P 25 cell (4.55%). The increase in conversion efficiency should be contributed to the dual effects of the enhanced light harvesting of up-conversion NaYF 4 :Yb 3+ , Er 3+ and light utilization of the top light scattering TiO 2 hollow microsphere.
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Chinese Physics B
·
2025
·
IF 1.5
Wenzhi Su,Kaiming Kan,Chuancheng Zhang,Yong Zou,Shoujun Din,Qingli Zhang
The influence of alkali and alkaline earth metal ion doping on the upconversion (UC) luminescence properties of Yb3+, Ho3+ co-doped NaBi(MoO4)2 (NBM) single crystals was systematically investigated. A series of Yb3+, Ho3+:NBM single crystals doped with Li+, K+, and Ca2+ ions were successfully grown using the Czochralski method. Their structural characteristics were analyzed through X-ray diffraction (XRD), transmission spectroscopy, and scanning electron microscopy (SEM), confirming a tetragonal crystal structure with space group I41/a. Under 980 nm and 450 nm laser excitation, the crystals exhibited distinct UC emission profiles, with dominant red and green emissions, respectively. Tauc plot analysis indicated that Ca2+ doping introduced donor levels within the crystal lattice, effectively narrowing the optical bandgap. Power-dependent luminescence studies revealed that both red and green UC emissions originated from two-photon excitation processes. Temperature-dependent photoluminescence measurements under both excitation wavelengths demonstrated that codoping with Li+, K+, and Ca2+ significantly enhanced the thermal stability of the luminescent properties. Furthermore, variable-temperature fluorescence lifetime analyses showed that alkali and alkaline earth metal ion doping effectively mitigated the luminescence lifetimes. Overall, the incorporation of Li+, K+, and Ca2+ ions was found to markedly improve both the UC luminescence intensity and thermal robustness of Yb3+, Ho3+:NBM single crystals, offering promising prospects for high-performance luminescent materials.
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CRYSTAL GROWTH & DESIGN
·
2024
·
IF 3.2
Chuancheng Zhang,Shoujun Ding,Wenzhi Su,Miaomiao Wang,Haitang Hu,Yong Zou,Wenpeng Liu,Qingli Zhang
Inhomogeneous broadening in disordered crystals has been widely recognized as a successful approach to enhance the spectral bandwidth of rare earth ions in optical spectra, and the Yb3+-doped mixed laser crystals are known as ultrafast pulse materials and have emerged as a hotspot recently. In this study, mixed sodium gadolinium/lanthanum double molybdate disordered laser crystals NaGd(1–x)La(x)(MoO4)2 with x = 0.3, 0.5, and 0.9 were grown by the Czochralski (Cz) method. The structure of as-grown crystals was investigated by XRD, SEM, FT-IR, and Raman experiments. The spectroscopic properties, including absorption, emission, and fluorescence decay characteristics, were investigated thoroughly. The NaGd0.5La0.5(MoO4)2 (NGLM) composite crystal exhibited an exceptionally broad absorption which reaches 70 nm (fwhm) at 980 nm, exceeding those of NaGd(MoO4)2 (NGM) and NaLa(MoO4)2 (NLM). Additionally, the electronic structures (band structure and density of states) of NGM, NGLM, and NLM were determined from the first-principles method combined with the PBE function. The calculations of defect formation energies under O-poor and O-rich conditions demonstrate that the +2 defects are easily generated in the undoped NGM crystal prepared under reducing atmospheres, and the calculation of absorption properties reveals that the black color of NGM without annealing is mainly attributed to intraband transitions between defect induction states and VBM or CBM. Moreover, the lifetimes of excited energy level 2F5/2 of Yb3+ were examined under different experimental environments to obtain the intrinsic radiative lifetime, and the emission cross section was calculated as 2.25 × 10–20 cm2 at 1016 nm. The features of the Yb3+:NaGd(1–x)La(x)(MoO4)2 crystal indicate the potential applications for ultrafast and broad tunable laser through slight regulation of the composite engineering strategy.
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JOURNAL OF MOLECULAR STRUCTURE
·
2024
·
IF 4
Qifeng Chen,Yu Yao,Shuo Zheng,Qianhong Shen,Libei Jiang,Qinhua Fang,Hui Yang
A novel Yb 3+ /Er 3+ co-doped BiOBr photocatalyst with 3D flowerlike hierarchical architectures were successfully fabricated through self-assembled process without any templates under hydrothermal conditions, and the structure and properties of the photocatalysts were characterized. The results indicate that Yb 3+ ions and Er 3+ ions are successfully doped into the lattice of BiOBr, and the as-obtained photocatalyst can respond the NIR light and emit red and green light due to the up-conversion effect of the rare-earth ions. Meanwhile, with co-doped Yb 3+ /Er 3+ ions content increasing, oxygen vacancy concentration in the photocatalyst rises. The oxygen vacancy will form the intermediate energy band, which can decrease the photon energy required for electronical transition, and thus help to utilize the luminous energy generated by up-conversion luminescence. Moreover, the appropriate introduction of defects (oxygen vacancy defect and impurity atom) can further promote the transfer and separation efficiency of photo-generated carriers. Hence, Yb 3+ /Er 3+ co-doped BiOBr photocatalyst exhibits enhanced photocatalytic properties under broad spectrum (UV/vis/NIR) excitation, which is about 4 times as high as that of pure BiOBr.
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Journal of Environmental Sciences
·
2021
·
IF 5.565
Yongjin Li,Yingying Zhang,Jiajing Wang,Youzhun Fan,Taizhong Xiao,Zhaoyi Yin,Tianhui Wang,Jianbei Qiu,Zhiguo Song
For better use of solar energy, the development of efficient broadband photocatalyst has attracted extraordinary attention. In this study, a ternary composite consisting of Sr 2 LaF 7 :Yb 3+ ,Er 3+ upconversion (UC) nanocrystals and Bi nanoparticles loaded BiOBr nanosheets with oxygen vacancies (OVs, SLFBB) was designed and synthesized by multistep solvent-thermal method. Mechanisms of in-situ formation of Bi nanoparticles and OVs in BiOBr/Sr 2 LaF 7 :Yb 3+ ,Er 3+ composites (SFLB) are clarified. The Bi metal and OVs enhanced the light-harvesting capacity in the region of visible-near-infrared (Vis-NIR), and promoted the separation of electron–hole (e − /h + ) pairs. Furthermore, the surface plasmon resonance (SPR) effect of Bi metal can improve the energy transfer from Sr 2 LaF 7 :Yb 3+ ,Er 3+ to BiOBr via nonradiative energy transfer process, resulting in enhancing the light utilization from upconverting NIR into Vis light. Due to the synergistic effects of UC function, SPR and OVs, the SFLBB exhibited obviously enhanced photocatalytic ability for the degradation of BPA with a rate of 8.9 × 10 −3 min −1 , which is about 2.78 times higher than 3.2 × 10 −3 min −1 of BiOBr (BOB) under UV–Vis-NIR light irradiation. This work provides a novel strategy for the project of high-efficiency Bismuth-based broadband photocatalysts, which is helpful to further understand the mechanism of enhanced photocatalysis by UC function and plasmonic effect.
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PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2026
·
IF 3.8
Viswadevarayalu Annavaram,Weicheng Xiang,Zihang Chai,Kangwei Zhu,Zaifa Pan
Enhanced quantum-cutting (QC) materials are highly desirable for promising applications such as solar cells. In this work, a series of Ce 3+ , Gd 3+ , and Yb 3+ tri-doped phosphors using Y 2 SiO 5 as the host were synthesized via a solid-state reaction. X-ray diffraction confirms that the dopants do not alter the monoclinic phase of Y 2 SiO 5 . Photoluminescence spectroscopy reveals that, the optimized tri-doped phosphor exhibits intense near-infrared (NIR) emission centered at 976 nm under UV excitation. Mechanism investigation reveals that Gd 3+ preferentially occupies the 7-coordinate Y2 site (associated with the Ce 3+ 392-nm emission), displacing Ce 3+ ions toward the 6-coordinate Y1 site (associated with the 425-nm emission). The Y1-site Ce 3+ emission at ∼425 nm (≈23,500 cm −1 ) is energetically closer to twice the Yb 3+ absorption energy (≈20,000 cm −1 ) than the Y2-site emission at ∼392 nm (≈25,500 cm −1 ), making the Y1 site more favorable for cooperative energy transfer to Yb 3+ pairs. This site-selective occupation effect significantly enhances the quantum-cutting efficiency. Furthermore, the synthesized tri-doped phosphor demonstrates superior performance in NIR phosphor-converted LEDs (pc-LEDs), achieving an electrical-to-optical conversion efficiency 1.55 times that of the co-doped counterpart. The output power of the tri-doped NIR LED is enhanced to 206.4% of that of the co-doped device. For solar cell applications, the short-circuit current density (J SC ) of the tri-doped device reaches 2.47 mA/cm 2 , with a power conversion efficiency (η) of 10.58%. The tri-doped phosphor solar cell exhibits an extra 0.1% enhancement in conversion efficiency compared to the co-doped counterpart. These results highlight the potential of Y 2 SiO 5 :Ce 3+ ,Gd 3+ ,Yb 3+ as an efficient spectral converter for boosting the energy yield of silicon photovoltaics.
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ACS Omega
·
2022
·
IF 4.132
Linxuan Wang,Weiqiang Yang,Liang Li,Shuai Hu,Maohui Yuan,Zining Yang,Kai Han,Hongyan Wang,Xiaojun Xu
In this work, a sequence of Nd3+, Yb3+, and Er3+ tridoped SrF2 nanocrystals (NCs) is synthesized by a hydrothermal method. Both the efficient near-infrared downconversion luminescence (DCL) and visible upconversion luminescence (UCL) of the Er3+ and Nd3+ ions are simultaneously observed and systematically demonstrated under dual-wavelength excitation (808 and 980 nm continuous-wave lasers). Subsequently, the SrF2:Nd3+/Yb3+/Er3+ (15/4/0.2 mol %) NCs with the strongest luminescence were utilized for detecting the metal ion concentrations under 808 nm excitation. The results reveal that both the UCL and DCL gradually decrease as the metal ion concentrations increase, and high sensitivity is obtained for Cu2+ ions with a detection limit of 0.22 nM (∼650 nm) and 0.63 nM (∼976 nm). In addition, these SrF2:Nd3+/Yb3+/Er3+ NCs are further demonstrated to achieve a solid-state display under 980 nm excitation, exhibiting obvious “red” and “green” patterns by varying the doping rare earth ion concentrations.
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PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Zhiyu Liu,Liang Chen,Congcong Piao,Jianhe Tang,Yu Liu,Yitong Lin,Dawei Fang,Jun Wang
A novel Z-scheme WO 3 :Yb 3+ ,Er 3+ /Ag/Ag 3 VO 4 /Ag photocatalyst is prepared via hydrothermal and calcination methods. In this system, WO 3 :Yb 3+ ,Er 3+ is used as an excellent up-conversion luminescent agent and highly active photocatalyst to broaden the light response range. Ag with SPR effect is regarded as electronic channel and cocatalyst to accelerate electron transfer and increase hydrogen production. The photocatalytic performance of Z-scheme WO 3 :Yb 3+ ,Er 3+ /Ag/Ag 3 VO 4 /Ag photocatalyst is assessed by levofloxacin degradation with synchronous hydrogen production. Some influence factors, sunlight irradiation time, sacrificial agent concentration and catalyst cycle number, are discussed. The emission light spectrum and energy conversion mechanism of WO 3 :Yb 3+ ,Er 3+ are studied. The photocatalyst gives prominent degradation ratio (90.44 %) and hydrogen production amount (489.02 μmol/g) under sunlight irradiation for 180 min. It shows a high stability and reusability in levofloxacin degradation with synchronous hydrogen production within five cycles. The possible mechanism of levofloxacin degradation with synchronous hydrogen production caused by Z-scheme WO 3 :Yb 3+ ,Er 3+ /Ag/Ag 3 VO 4 /Ag photocatalyst is proposed.
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BIOMATERIALS
·
2011
·
IF 7.883
Ao Xia,Yuan Gao,Jing Zhou,Chunyan Li,Tianshe Yang,Dongmei Wu,Limin Wu,Fuyou Li
New core–shell structured NaYF 4 :Yb 3+ ,Tm 3+ @Fe x O y nanocrystals , with 20 nm Yb 3+ ,Tm 3+ -co-doped NaYF 4 nanocrystals as a core and 5 nm Fe x O y nanocrystals as a shell, have been synthesized and characterized by TEM and XRD analysis . These core–shell nanocrystals exhibit excellent near-infrared upconversion luminescence (UCL) emission at 800 nm under excitation by a continuous-wave 980 nm laser and superparamagnetic properties with a saturation magnetization (Ms) of ∼12 emu/g. Water-soluble nanocrystals were obtained by surface ligand exchange of oleic acid-coated precursor nanocrystals, and their internalization within living cells has been investigated by laser scanning UCL microscopy. Furthermore, the obtained core–shell nanocrystals have been applied in dual-modality T 2 -enhanced magnetic resonance (MR) and UCL imaging in vivo of the lymphatic system. Moreover, the toxicity of NaYF 4 :Yb 3+ ,Tm 3+ @Fe x O y nanocrystals has also been evaluated by MTT assay, IC50 values, and histological analysis of lymphatic node sections.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Xinwen Liu,Bingchu Mei,Guolong Tan
Lanthanide-ion-doped red upconversion (UC) fluorescent materials with excellent signal-to-noise ratio, stability, and red-green luminous intensity ratio have proven of tremendous research importance for biomedical, three-dimensional (3D) displays, sensors, and other sectors. In this study, xYb, 1Er: Sr 5 (PO 4 ) 3 F (S-FAP) (x=0–5 at%) transparent ceramics with outstanding optical quality were fabricated by hot pressing the co-precipitation powder with high sintering activity. The energy dispersive X-ray (EDX) results showed that the trivalent lanthanide ions were evenly doped into the S-FAP ceramic lattice. Increased Yb 3+ doping considerably restricted the growth of ceramic grain size, which should be attributable to a decrease in sintering activity under high Yb doping conditions. The co-doping of Yb 3+ successfully resulted in a significant improvement in up/down conversion efficiency via effective energy transfer mechanisms and the optimization of the electron population at the energy level of red-green emission. Furthermore, single-band red upconversion luminescence with the greatest red-green upconversion luminescence integral intensity ratio of 125.74 was discovered under 980 nm laser pumping at room temperature. The energy transition process involved in the phenomenon of the up-conversion luminescence intensity shift of red-green emission has been thoroughly examined. Finally, the noncontact optical thermometric ability based on fluorescence intensity ratio (FIR) technology showed that the maximum absolute sensitivity (Sa) of the 5Yb1Er sample in the temperature range of 320–556 K is 1.1×10 −3 K −1 , implying the possible use of Yb/Er-doped S-FAP transparent ceramics in the field of optical thermometers.
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高影响因子
Nanoscale Research Letters
·
2022
·Vol. 17
·期 1
·1-12
·
IF 5.418
Wang Linxuan,Li Liang,Yuan Maohui,Yang Zining,Han Kai,Wang Hongyan,Xu Xiaojun
Spectrally determination of temperature based on the lanthanide-doped nanocrystals (NCs) is a vital strategy to noninvasively measure the temperature in practical applications. Here, we synthesized a series of SrF 2 :Yb 3+ /Ho 3+ NCs and simultaneously observed the efficient visible upconversion luminescence (UCL) and near-infrared (NIR) downconversion luminescence (DCL) under 980, 940 and 915 nm excitations. Subsequently, these NCs were further utilized for thermometers based on the Boltzmann (thermally coupled levels, TCLs) and non-Boltzmann (non-thermally coupled levels, NTCLs) of Ho 3+ ions in the first (~ 650 nm), second (~ 1012 nm) and third (~ 2020 nm) biological windows (BW-I, BW-II and BW-III) under tri-wavelength excitations. The thermometric parameters including the relative sensitivity ( \(S_{{\text{r}}}\) ) and temperature uncertainty ( \(\delta T\) ) are quantitatively determined on the I 648 / I 541 (BW-I), I 1186 / I 1012 (BW-II), and I 1950 / I 2020 (BW-III) transitions of Ho 3+ ions in the temperature range of 303–573 K. Comparative experimental results demonstrated that the thermometer has superior performances.
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高影响因子
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