High quality BaWO4 nanowire bundles have been synthesized in toluene-sodium dodecylbenzene sulphonate (SDBS)-small amount PEG20000-H2O reverse micelle system. XRD result shows that the obtained BaWO4 belongs to tetrag...High quality BaWO4 nanowire bundles have been synthesized in toluene-sodium dodecylbenzene sulphonate (SDBS)-small amount PEG20000-H2O reverse micelle system. XRD result shows that the obtained BaWO4 belongs to tetragonal phase with scheelite structure. TEM results demonstrate that the obtained BaWO4 nanowire bundles have high aspect-ratio (>650). The experimental results confirm that PEG20000 plays a key role for the formation of BaWO4 nanowire bundles. Other factors which influence the morphology and crystallinity of the product are also briefly discussed. Moreover, the obtained BaWO4 nanowire bundles exhibit strong photoluminescence centered at 397.3 nm with λex=343.5 nm at room temperature, which is different from the bulk BaWO4 crystals.展开更多
BaWO4：Pr^3＋ （hereafter BWO：Pr） microcrystals were prepared via a hydrothermal route, and characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, photoluminescence excitation and emission...BaWO4：Pr^3＋ （hereafter BWO：Pr） microcrystals were prepared via a hydrothermal route, and characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, photoluminescence excitation and emission spectra. The as-prepared products with different morphologies of egg-shape rod, olive-like, and quasi-sphere were obtained by the addition of the surfactants and chelating agents. The emis-sion spectra of BWO：Pr microcrystals showed the strong red emission （642 nm） assigned to the Pr^3＋ ions of 3P0→3F2 transition with blue ex-citation （484.6 nm, 3H4→3P0）.展开更多
In this work, BaWO4 nanospheres were successfully prepared by hydrothermal process. The bipolar resistive switching behavior of Ag/BaWO4/FTO device is observed. Moreover, this resistive switching behavior can be modul...In this work, BaWO4 nanospheres were successfully prepared by hydrothermal process. The bipolar resistive switching behavior of Ag/BaWO4/FTO device is observed. Moreover, this resistive switching behavior can be modulated by white light. The device can maintain superior stability in the dark and under white-light illumination. This study is useful for developing the light-controlled nonvolatile memory devices.展开更多
The optical quality of Er^3＋, yb^3＋： BaWO4 crystal was gown by Czochralski method. Absorption spectra were measured and energy levels were assigned. According to Judd-Ofelt theory, the spectral strength parameters ...The optical quality of Er^3＋, yb^3＋： BaWO4 crystal was gown by Czochralski method. Absorption spectra were measured and energy levels were assigned. According to Judd-Ofelt theory, the spectral strength parameters of Er^3＋ ion were fitted to beΩ2 =0.3926 x 10^-20 cm^2, Ω4 =0.0721×10^-20 cm^2, Ω6 =0.0028 ×10.20 cm^2. Emission peaks centered at around 523,544 and 670 nm were observed under 334 nm He-Cd laser excitation and emission peaks centered at 1001 and 1534 nm were detected under 976 nm laser excitation. Strong green emission was also observed when the crystal was pumped with 808 nm and 976 nm laser. The mechanisms of frequency upconversion and sensitization were analyzed.展开更多
Nearly all displacive transitions have been considered to be continuous or second order, and the rigid unit mode （RUM） provides a natural candidate for the soft mode. However, in-situ X-ray diffraction and Raman mea...Nearly all displacive transitions have been considered to be continuous or second order, and the rigid unit mode （RUM） provides a natural candidate for the soft mode. However, in-situ X-ray diffraction and Raman measurements show clearly the first-order evidences for the scheelite-to-fergusonite displacive transition in SaWO4： a 1.6% volume collapse, coexistence of phases, and hysteresis on release of pressure. Such first-order signatures are found to be the same as the soft modes in BaWO4, which indicates the scheelite-to-fergusonite displacive phase transition hides a deeper physical mechanism. By the refinement of atomic displacement parameters, we further show that the first-order character of this phase transition stems from a coupling of large compression of soft BaOs polyhedrons to the small displacive distortion of rigid WO4 tetrahedrons. Such a coupling will lead to a deeper physical insight in the phase transition of the common scheelite-structured compounds.展开更多
This research investigated the effect of different contents of Tm3＋ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4：yb3＋/Tm3＋ nano-crystal synthesized by the hydrothermal metho...This research investigated the effect of different contents of Tm3＋ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4：yb3＋/Tm3＋ nano-crystal synthesized by the hydrothermal method. The results indicated that lumines- cence intensity reached the strongest when CTm=1.0 mol.% and Cyb/CTm=2：1. X-ray diffraction revealed the tetragonal system of BaWO4：Yb3＋/Tm3＋ and the grain sizes were between 31 and 45 nm according to Scherrer equation. The results of X-ray diffraction and scanning electron microscopy were similar. Four emission peaks at 454, 475, 647 and 790 nm including two blue emission peaks and two red emission peaks, corresponding to ID2→3F4, 1G4→3H6, IG4→3F4 and 3H4→3H6 transitions of Tm3＋, were observed under excitation of 980 nm semiconductor laser. Blue emissions at 454 and 475 um were four-photon and three-photon absorption respec- tively in accordance with the relationship between luminescence intensity and pump power.展开更多
BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. R...BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. Results showed that the solvents composition—volume ratio of 4-dioxane and distilled water—played the key role in the formation of BaWO4 Nanorods. Furthermore, the strong vibration at 925 cm﹣1 on its Raman spectrum indicated that the BaWO4 nanorods is good at stimulating Raman scattering in transient and steady-state, making it as a promising candidate material for laser with self-raman conversion of radiation inside the active medium.展开更多
The poor stability of lead halide perovskites poses a critical challenge for realizing potential applications.Constructing latticed-matched perovskite/BaWO_(4) heterostructures is highly advantageous for achieving enh...The poor stability of lead halide perovskites poses a critical challenge for realizing potential applications.Constructing latticed-matched perovskite/BaWO_(4) heterostructures is highly advantageous for achieving enhanced stability.However,there is limited knowledge about the interfacial properties.Herein,we conducted combined first-principles and experimental investigations of the perovskite/BaWO_(4) heterostructures in this work.First,eight different interfacial configurations were constructed and investigated systematically.The influence of surface terminations on interfacial properties was examined through the adhesive strength and electronic structures.The results of adhesion work suggest that the MAPbBr_(3)/BaWO_(4) configurations possess stronger interfacial interaction than the CsPbBr_(3)/BaWO_(4) configurations.The formation of BaW/PbBr and BaW/MAPb configurations was more facile compared to their counterparts.The interfacial charge transfer direction,potential difference,and valence band edges of the perovskite/BaWO_(4) heterostructures were found to be significantly influenced by the surface termination of BaWO_(4).The absorption intensity of the perovskite/BaWO_(4) heterostructures is significantly affected by the surface termination of the perovskite.Finally,the CsPbBr_(3)/BaWO_(4) heterostructure was fabricated and characterized,thereby validating the first-principles predictions.This study provides a fundamental contribution to establishing perovskite/BaWO_(4) heterostructures for the advancement of perovskite-based optoelectronic devices.展开更多
文摘High quality BaWO4 nanowire bundles have been synthesized in toluene-sodium dodecylbenzene sulphonate (SDBS)-small amount PEG20000-H2O reverse micelle system. XRD result shows that the obtained BaWO4 belongs to tetragonal phase with scheelite structure. TEM results demonstrate that the obtained BaWO4 nanowire bundles have high aspect-ratio (>650). The experimental results confirm that PEG20000 plays a key role for the formation of BaWO4 nanowire bundles. Other factors which influence the morphology and crystallinity of the product are also briefly discussed. Moreover, the obtained BaWO4 nanowire bundles exhibit strong photoluminescence centered at 397.3 nm with λex=343.5 nm at room temperature, which is different from the bulk BaWO4 crystals.
基金supported by the Natural Science Foundation of Jiangxi Province (2010GZW0022)the Science Program of the Education Office of Jiangxi Province (GJJ10472)
文摘BaWO4：Pr^3＋ （hereafter BWO：Pr） microcrystals were prepared via a hydrothermal route, and characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, photoluminescence excitation and emission spectra. The as-prepared products with different morphologies of egg-shape rod, olive-like, and quasi-sphere were obtained by the addition of the surfactants and chelating agents. The emis-sion spectra of BWO：Pr microcrystals showed the strong red emission （642 nm） assigned to the Pr^3＋ ions of 3P0→3F2 transition with blue ex-citation （484.6 nm, 3H4→3P0）.
基金supported by the National Nature Science Foundation of China (Grant No. 51372209)
文摘In this work, BaWO4 nanospheres were successfully prepared by hydrothermal process. The bipolar resistive switching behavior of Ag/BaWO4/FTO device is observed. Moreover, this resistive switching behavior can be modulated by white light. The device can maintain superior stability in the dark and under white-light illumination. This study is useful for developing the light-controlled nonvolatile memory devices.
基金Project supported by the Key Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences
文摘The optical quality of Er^3＋, yb^3＋： BaWO4 crystal was gown by Czochralski method. Absorption spectra were measured and energy levels were assigned. According to Judd-Ofelt theory, the spectral strength parameters of Er^3＋ ion were fitted to beΩ2 =0.3926 x 10^-20 cm^2, Ω4 =0.0721×10^-20 cm^2, Ω6 =0.0028 ×10.20 cm^2. Emission peaks centered at around 523,544 and 670 nm were observed under 334 nm He-Cd laser excitation and emission peaks centered at 1001 and 1534 nm were detected under 976 nm laser excitation. Strong green emission was also observed when the crystal was pumped with 808 nm and 976 nm laser. The mechanisms of frequency upconversion and sensitization were analyzed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11179030 and 90714011)the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KJCX2-SW-N20)
文摘Nearly all displacive transitions have been considered to be continuous or second order, and the rigid unit mode （RUM） provides a natural candidate for the soft mode. However, in-situ X-ray diffraction and Raman measurements show clearly the first-order evidences for the scheelite-to-fergusonite displacive transition in SaWO4： a 1.6% volume collapse, coexistence of phases, and hysteresis on release of pressure. Such first-order signatures are found to be the same as the soft modes in BaWO4, which indicates the scheelite-to-fergusonite displacive phase transition hides a deeper physical mechanism. By the refinement of atomic displacement parameters, we further show that the first-order character of this phase transition stems from a coupling of large compression of soft BaOs polyhedrons to the small displacive distortion of rigid WO4 tetrahedrons. Such a coupling will lead to a deeper physical insight in the phase transition of the common scheelite-structured compounds.
基金supported by National Natural Science Foundation of China Youth Science (20901011)Jilin Science and Technology Bureau (20091510)
文摘This research investigated the effect of different contents of Tm3＋ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4：yb3＋/Tm3＋ nano-crystal synthesized by the hydrothermal method. The results indicated that lumines- cence intensity reached the strongest when CTm=1.0 mol.% and Cyb/CTm=2：1. X-ray diffraction revealed the tetragonal system of BaWO4：Yb3＋/Tm3＋ and the grain sizes were between 31 and 45 nm according to Scherrer equation. The results of X-ray diffraction and scanning electron microscopy were similar. Four emission peaks at 454, 475, 647 and 790 nm including two blue emission peaks and two red emission peaks, corresponding to ID2→3F4, 1G4→3H6, IG4→3F4 and 3H4→3H6 transitions of Tm3＋, were observed under excitation of 980 nm semiconductor laser. Blue emissions at 454 and 475 um were four-photon and three-photon absorption respec- tively in accordance with the relationship between luminescence intensity and pump power.
文摘BaWO4 nanorods have been successfully synthesized in w/o microemulsion system containing barium ions via a simple reaction between Ba2+ and . The BaWO4 Nanorods were characterized by XRD, TEM, and SEM, respectively. Results showed that the solvents composition—volume ratio of 4-dioxane and distilled water—played the key role in the formation of BaWO4 Nanorods. Furthermore, the strong vibration at 925 cm﹣1 on its Raman spectrum indicated that the BaWO4 nanorods is good at stimulating Raman scattering in transient and steady-state, making it as a promising candidate material for laser with self-raman conversion of radiation inside the active medium.
基金supported by the National Natural Science Foundation of China(Grant No.12381240132)the China Scholarship Council(Grant No.202308410380)+1 种基金the Postgraduate Education Reform and Quality Improvement Project of Henan Province(Grant No.YJS2023JD60)the Henan International Joint Laboratory of Nanocomposite Sensing Materials.
文摘The poor stability of lead halide perovskites poses a critical challenge for realizing potential applications.Constructing latticed-matched perovskite/BaWO_(4) heterostructures is highly advantageous for achieving enhanced stability.However,there is limited knowledge about the interfacial properties.Herein,we conducted combined first-principles and experimental investigations of the perovskite/BaWO_(4) heterostructures in this work.First,eight different interfacial configurations were constructed and investigated systematically.The influence of surface terminations on interfacial properties was examined through the adhesive strength and electronic structures.The results of adhesion work suggest that the MAPbBr_(3)/BaWO_(4) configurations possess stronger interfacial interaction than the CsPbBr_(3)/BaWO_(4) configurations.The formation of BaW/PbBr and BaW/MAPb configurations was more facile compared to their counterparts.The interfacial charge transfer direction,potential difference,and valence band edges of the perovskite/BaWO_(4) heterostructures were found to be significantly influenced by the surface termination of BaWO_(4).The absorption intensity of the perovskite/BaWO_(4) heterostructures is significantly affected by the surface termination of the perovskite.Finally,the CsPbBr_(3)/BaWO_(4) heterostructure was fabricated and characterized,thereby validating the first-principles predictions.This study provides a fundamental contribution to establishing perovskite/BaWO_(4) heterostructures for the advancement of perovskite-based optoelectronic devices.
