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Plasmon Assisted Highly Efficient Visible Light Catalytic CO_(2) Reduction Over the Noble Metal Decorated Sr-Incorporated g-C_(3)N_(4) 被引量:6
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作者 Muhammad Humayun Habib Ullah +4 位作者 Lang Shu Xiang Ao Asif Ali Tahir Chungdong Wang Wei Luo 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第12期416-433,共18页
The photocatalytic performance of g-C_(3)N_(4) for CO_(2) conversion is still inadequate by several shortfalls including the instability,insu cient solar light absorption and rapid charge carrier's recombination r... The photocatalytic performance of g-C_(3)N_(4) for CO_(2) conversion is still inadequate by several shortfalls including the instability,insu cient solar light absorption and rapid charge carrier's recombination rate. To solve these problems,herein,noble metals(Pt and Au)decorated Sr-incorporated g-C_(3)N_(4) photocatalysts are fabricated via the simple calcination and photo-deposition methods. The Sr-incorporation remarkably reduced the g-C_(3)N_(4) band gap from 2.7 to 2.54 eV,as evidenced by the UV–visible absorption spectra and the density functional theory results. The CO_(2) conversion performance of the catalysts was evaluated under visible light irradiation. The Pt/0.15 Sr-CN sample produced 48.55 and 74.54 μmol h-1 g-1 of CH_(4) and CO,respectively.These amounts are far greater than that produced by the Au/0.15 Sr-CN,0.15 Sr-CN,and CN samples. A high quantum e ciency of 2.92% is predicted for the Pt/0.15 Sr-CN sample. Further,the stability of the photocatalyst is confirmed via the photocatalytic recyclable test. The improved CO_(2) conversion performance of the catalyst is accredited to the promoted light absorption and remarkably enhanced charge separation via the Sr-incorporated mid gap states and the localized surface plasmon resonance e ect induced by noble metal nanoparticles.This work will provide a new approach for promoting the catalytic e ciency of g-C_(3)N_(4) for e cient solar fuel production. 展开更多
关键词 g-C_(3)N_(4) Sr-incorporation Noble metal deposition Density functional theory Energy applications
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Perovskite-type lanthanum ferrite based photocatalysts:Preparation,properties,and applications 被引量:6
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作者 Muhammad Humayun Habib Ullah +4 位作者 Muhammad Usman Aziz Habibi-Yangjeh Asif Ali Tahir Chundong Wang Wei Luo 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第3期314-338,I0009,共26页
Clean energy and a sustainable environment are grand challenges that the world is facing which can be addressed by converting solar energy into transportable and storable fuels(chemical fuel).The main scientific and t... Clean energy and a sustainable environment are grand challenges that the world is facing which can be addressed by converting solar energy into transportable and storable fuels(chemical fuel).The main scientific and technological challenges for efficient solar energy conversion,energy storage,and environmental applications are the stability,durability,and performance of low-cost functional materials.Among different nanomaterials,perovskite type LaFeO_(3)has been extensively investigated as a photocatalyst due to its abundance,high stability,compositional and structural fexibility,high electrocatalytic activity,efficient sunlight absorption,and tunable band gap and band edges.Hence,it is urgent to write a comprehensive review to highlight the trend,challenges,and prospects of LaFeO_(3)in the field of photocatalytic solar energy conversion and environment purification.This critical review summarizes the history and basic principles of photocatalysis.Further,it reviews in detail the LaFeO_(3),applications,shortcomings,and activity enhancement strategies including the design of nanostructures,elemental doping,and heterojunctions construction such as Type-I,Type-II,Z-Type,and uncommon heterojunctions.Besides,the optical and electronic properties,charge carriers separation,electron transport phenomenon and alignment of the band gaps in LaFeO_(3)-based heterostructures are comprehensively discussed. 展开更多
关键词 Perovskite-type LaFeO_(3) Solar fuel PHOTOCATALYSIS Doping HETEROSTRUCTURES
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Silica-based microcavity fabricated by wet etching 被引量:1
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作者 龙浩 杨文 +1 位作者 应磊莹 张保平 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第5期195-198,共4页
Silica whispering gallery mode(WGM) microcavities were fabricated by the buffered oxide etcher and potassium hydroxide wet etching technique without any subsequent chemical or laser treatments. The silicon pedestal ... Silica whispering gallery mode(WGM) microcavities were fabricated by the buffered oxide etcher and potassium hydroxide wet etching technique without any subsequent chemical or laser treatments. The silicon pedestal underneath was an octagonal pyramid, thus providing a pointed connection area with the top silica microdisk while weakly influencing the resonance modes. The sidewalls of our microdisks were wedge shaped, which was believed to be an advantage for the mode confinement. Efficient coupling from and to the 60 μm diameter microdisk structure was achieved using tapered optical fibres, exhibiting a quality factor of 1.5×10^4 near a wavelength of 1550 nm. Many resonance modes were observed, and double transverse electric modes were identified by theoretical calculations. The quality factor of the microdisks was also analysed to deduce the cavity roughness. The wet etching technique provides a more convenient avenue to fabricate WGM microdisks than conventional fabrication methods. 展开更多
关键词 etching gallery fibres silica pyramid roughness subsequent confinement hydroxide shaped
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A New Mixed-metal Monophosphate:Ba2Bi2Co(PO4)4
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作者 张炜龙 郭振刚 +1 位作者 陈达贵 程文旦 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第6期1027-1033,共7页
A new member of mixed-metal Ba2Bi2M-Ⅱ(PO4)4 monophosphate, namely Ba2Bi2Co(PO4)4, was synthesized by solid state method and characterized by X-ray single-crystal diffraction and powder diffraction for the first t... A new member of mixed-metal Ba2Bi2M-Ⅱ(PO4)4 monophosphate, namely Ba2Bi2Co(PO4)4, was synthesized by solid state method and characterized by X-ray single-crystal diffraction and powder diffraction for the first time. It crystallizes in the orthorhombic system with space group Pnma(No. 62) and features a 3D architecture built up of adjacent zig-zag linear structures of [CoP4O(16)]∞ along [100], and further connected by [Bi2O(11)] dimers to form a 3D framework, where the Ba2+ are located in the free space. The stereochemical activity of the Bi3+ lone pair has also been discussed. The result of magnetic property measurement confirms the antiferromagnetic property of Ba2Bi2Co(PO4)4. 展开更多
关键词 mixed-metal monophosphate solid-state synthesis crystal structure stereoactivity magnetic property
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Synthesis,Single-crystal Structure,and Computational Studies of a Yavapaiite Structure Compound:Pb(Sb0.5Fe0.5)(PO4)2
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作者 张炜龙 陈达贵 +3 位作者 李小燕 郭振刚 林晨升 余运龙 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2018年第1期75-82,共8页
The single crystals and powder of a Yavapaiite Structure phosphate,namely,PbSb0.5Fe0.5(PO4)2,were synthesized by solid state method and characterized by X-ray single-crystal diffraction and powder diffraction.The ti... The single crystals and powder of a Yavapaiite Structure phosphate,namely,PbSb0.5Fe0.5(PO4)2,were synthesized by solid state method and characterized by X-ray single-crystal diffraction and powder diffraction.The title compound crystallizes in the monoclinic system,space group C2/c(No.15) with a = 16.716(4),b = 5.186(7),c = 8.130(2)A,β = 114.93(6)°,Z = 4,R(I 〉 2s(I)) = 0.0430,R indices(all data) = 0.0460,and T = 293(2) K.The title compound belongs to the Yavapaiite Structure A^(Ⅱ)M^(Ⅳ)(PO4)2 compounds,and the Sb1 atom and Fe1 atoms occupy the same site(M) and their occupancy factors are refined to be 0.5 and 0.5 having a sum occupancy factor of 1.0.Its structure consists of [M(PO)4]n^2n- layers running parallel to the(b,c) plane built up of cornerconnected MO6 octahedra and PO4 tetrahedra.Additionally,the calculations of energy band structure,and density of states have been performed with the density functional theory method.The studies of computational calculation and UV experimental results show that the new compound is an indirect band-gap insulator. 展开更多
关键词 phosphates solid-state syntheses single crystal yavapaiite structure computational calculation
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Effect of In Diffusion on the Property of Blue Light-Emitting Diodes
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作者 曾勇平 刘文杰 +6 位作者 翁国恩 赵婉茹 左海杰 余健 张江勇 应磊莹 张保平 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第6期80-83,共4页
In diffusion to blue light-emitting diode (LED) wafers is performed by the inductive coupled plasma (ICP) treatment of a covering layer of indium tin oxide (ITO) on the wafer surface. The electrical property of ... In diffusion to blue light-emitting diode (LED) wafers is performed by the inductive coupled plasma (ICP) treatment of a covering layer of indium tin oxide (ITO) on the wafer surface. The electrical property of the p- type contact is improved and the redshift of photoluminescence (PL) from the InGaN quantum well of the wafer is found. Measurements by x-ray photoelectron spectroscopy (XPS) demonstrate that In atoms have diffused into p-GaN. Reflectance spectra of the sample surface reveal the variation caused by the ICP treatment. A model of compensation of the in-plane strain of the InGaN layer is used to explain the redshift of the PL data. Finally, LEDs are fabricated by using as-grown and ICP-treated wafers and their properties are compared. Under an injection current of 20mA, LEDs with ICP-induced In doping show a decrease of 0.3 V in the forward voltage and an increase of 23% in the light output, respectively. 展开更多
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Temperature Dependence of Emission Properties of Self-Assembled InGaN Quantum Dots
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作者 赵婉茹 翁国恩 +4 位作者 梁明明 李增成 刘建平 张江勇 张保平 《Chinese Physics Letters》 SCIE CAS CSCD 2014年第11期70-73,共4页
Emission properties of self-assembled green-emitting InGaN quantum dots (QDs) grown on sapphire substrates by using metal organic chemical vapor deposition are studied by temperature-dependent photoluminescence (PL... Emission properties of self-assembled green-emitting InGaN quantum dots (QDs) grown on sapphire substrates by using metal organic chemical vapor deposition are studied by temperature-dependent photoluminescence (PL) measurements. As temperature increases (15-300K), the PL peak energy shows an anomalous V-shaped (redshift blueshift) variation instead of an S-shaped (redshift-blueshift-redshift) variation, as observed typically in green-emitting InGaN/GaN multi-quantum wells (MOWs). The PL full width at half maximum (FWHM) also shows a V-shaped (decrease-increase) variation. The temperature dependence of the PL peak energy and FWHM of QDs are well explained by a model similar to MOWs, in which carriers transferring in localized states play an important role, while the confinement energy of localized states in the QDs is significantly larger than that in MOWs. By analyzing the integrated PL intensity, the larger confinement energy of localized states in the QDs is estimated to be 105.9meV, which is well explained by taking into account the band-gap shrinkage and carrier thermalization with temperature. It is also found that the nonradiative combination centers in QD samples are much less than those in QW samples with the same In content. 展开更多
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Co-assembly of chiral copper(Ⅰ)complexes and achiral polymer for enhanced circularly polarized luminescence
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作者 Ting Liu Muxin Yu +6 位作者 Yangxingyu Ye Yunfang Zhao Zhijia Li Zhiyuan Wu Feilong Jiang Lian Chen Maochun Hong 《Science China Chemistry》 2025年第3期935-942,共8页
Circularly polarized luminescence(CPL)has attracted growing attention for their promising applications in chiral functional devices.Achieving CPL materials with both high luminescence dissymmetry factors(g_(lum))and e... Circularly polarized luminescence(CPL)has attracted growing attention for their promising applications in chiral functional devices.Achieving CPL materials with both high luminescence dissymmetry factors(g_(lum))and emission efficiency is attractive but remains great challenges.In this study,a pair of chiral Cu(Ⅰ)complexes named R/S-CuI with C_(2) symmetry were synthesized,exhibiting no emission in solution and weak CPL with g_(lum)=±3.3×10^(-3)in crystalline state.Transparent chiral films(R/S-CuI-film)were developed through the co-assembly of R/S-CuI and achiral polymer PMMA.The films show bright green luminescence with the quantum yields about 200 times higher than those in crystalline state.Meanwhile,the maximum|g_(lum)|value is also amplified by approximately 2.5 times,reaching to 8.7×10^(-3).Mechanism investigation suggests that the notable enhancement of luminescence efficiency can be ascribed to the restriction of the intramolecular motions and the elimination of the oxygen quenching effect,while the improvement in g_(lum)values may be explained by the chirality transfer from the axially chiral molecule R/S-CuI to the achiral polymer PMMA.Furthermore,R/S-CuI-film were used for advanced information encryption applications based on its CPL characteristics.This work may provide new inspirations for the construction of CPL-active films with high performance,thereby expediting their further development. 展开更多
关键词 metal-organic complexes circularly polarized luminescence achiral polymer chiral film chirality transfer
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Quantum dot vertical-cavity surface-emitting lasers covering the ‘green gap’ 被引量:7
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作者 Yang Mei Guo-En Weng +7 位作者 Bao-Ping Zhang Jian-Ping Liu Werner Hofmann Lei-Ying Ying Jiang-Yong Zhang Zeng-Cheng Li Hui Yang Hao-Chung Kuo 《Light: Science & Applications》 SCIE EI CAS CSCD 2016年第1期275-281,共7页
Semiconductor vertical-cavity surface-emitting lasers(VCSELs)with wavelengths from 491.8 to 565.7 nm,covering most of the‘green gap’,are demonstrated.For these lasers,the same quantum dot(QD)active region was used,w... Semiconductor vertical-cavity surface-emitting lasers(VCSELs)with wavelengths from 491.8 to 565.7 nm,covering most of the‘green gap’,are demonstrated.For these lasers,the same quantum dot(QD)active region was used,whereas the wavelength was controlled by adjusting the cavity length,which is difficult for edge-emitting lasers.Compared with reports in the literature for green VCSELs,our lasers have set a few world records for the lowest threshold,longest wavelength and continuous-wave(CW)lasing at room temperature.The nanoscale QDs contribute dominantly to the low threshold.The emitting wavelength depends on the electron–photon interaction or the coupling between the active layer and the optical field,which is modulated by the cavity length.The green VCSELs exhibit a low-thermal resistance of 915 kW^(−1),which benefits the CW lasing.Such VCSELs are important for small-size,low power consumption full-color displays and projectors. 展开更多
关键词 GaN INGAN quantum dot vertical-cavity surface-emitting laser wide-gap semiconductor
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高质量的AlGaN外延结构和UVC垂直腔面发射激光器的实现 被引量:2
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作者 郑重明 王玉坤 +6 位作者 胡建正 郭世平 梅洋 龙浩 应磊莹 郑志威 张保平 《Science China Materials》 SCIE EI CAS CSCD 2023年第5期1978-1988,共11页
AlGaN基垂直腔面发射激光器(VCSEL)因其优越的材料性质和器件优点吸引了很多关注.然而,由于材料外延生长和器件制备工艺的局限,AlGaN基VCSEL制备很困难.本工作通过侧向外延生长技术制备了高质量的AlGaN多量子阱(MQWs)结构的外延片,并通... AlGaN基垂直腔面发射激光器(VCSEL)因其优越的材料性质和器件优点吸引了很多关注.然而,由于材料外延生长和器件制备工艺的局限,AlGaN基VCSEL制备很困难.本工作通过侧向外延生长技术制备了高质量的AlGaN多量子阱(MQWs)结构的外延片,并通过X射线衍射(XRD)和光致发光(PL)实验对外延片进行了分析.XRD测量显示,外延片中的AlN模板层几乎是弛豫的,刃位错密度为10^(9)cm^(-2).随后,生长的AlGaN/AlN超晶格(SL)层被用来减少刃位错密度,使得量子阱中的位错密度为10^(8)cm^(-2).根据PL测试结果,MQWs的内量子效率(IQE)为62%,且在室温下的发光以辐射复合为主.通过激光剥离(LLO)和化学机械抛光(CMP)技术,将这些外延片制备成UVC VCSEL.经过这些工艺,MQWs的晶体质量没有受到影响,还在抛光之后的表面观察到了UVC波段的受激辐射.这些AlGaN基UVC VCSEL在275.91,276.28和277.64 nm实现了激射,最小激射阈值为0.79 MW cm^(-2). 展开更多
关键词 ALGAN vertical-cavity surface-emitting lasers epitaxial lateral overgrowth laser lift-off UVC
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A Mixed Metal Phosphate Containing Two Types of Phosphoric Anionic Groups: Cs2Ga4(P2O7)2(P4O(13))
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作者 ZHANG Wei-Long GUO Zhen-Gang +3 位作者 CHEN Da-Gui HE Jian-Gang ZHANG Hao LI Xiao-Yan 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2020年第2期329-339,187,共12页
A new mixed metal phosphate of Cs2Ga4P8O(27), which also can be written as Cs2Ga4(P2O7)2(P4O(13)), was synthesized by high temperature solid state syntheses and structurally characterized by X-ray single-crystal diffr... A new mixed metal phosphate of Cs2Ga4P8O(27), which also can be written as Cs2Ga4(P2O7)2(P4O(13)), was synthesized by high temperature solid state syntheses and structurally characterized by X-ray single-crystal diffraction for the first time. The title compound crystallizes in monoclinic system with space group P21/c(No.14), and features a 3D framework which can be considered as alternating layers of {Ga2(P4O(13))}n and {Ga2(P2O7)2}n^(2n-) parallel to the bc plane further connected by Ga-O-P linkages, where Cs^+ cations are located in the free space between two adjacent layers to charge the valence. The Ga^(3+) cations in the compound contain two kinds of coordination models(4 and 6). Furthermore, the title compound coexists of two phospho-ric anionic groups which are non-condensed horseshoe-shaped(P4O(13)) and two(P2O7) with different symmetries. The density functional theory calculations indicate that Cs2Ga4P8O(27) is a direct band gap insulator with flat valence and dispersive conduction bands and a band gap of 4.13 eV. 展开更多
关键词 solid-state SYNTHESES MIXED METAL PHOSPHATES crystal structure phosphoric ANIONIC groups horseshoe-shaped coordination model
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