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980 nm Near-Infrared Light-Emitting Diode Using All-Inorganic Perovskite Nanocrystals Doped with Ytterbium Ions

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Tsinghua Science and Technology 2024年第1期29卷 207-215页

作者： Zhenglan Ye Taoran Liu Dan Chen Yazhou Yang Jiayi Li Yaqing Pang Xiangquan Liu Yuhua Zuo Jun Zheng Zhi Liu Buwen Cheng State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Intelligent Network Research Institute Zhejiang LabHangzhou 311100China

All-inorganic perovskite(CsPbX3)nanocrystals(NCs)have recently been widely investigated as versatile solution-processable light-emitting materials.Due to its wide-bandgap nature,the all-inorganic perovskite NC Light-Emitting Diode(LED)is limited to the visible region(400-700 nm).A particularly difficult challenge lies in the practical application of perovskite NCs in the infrared-spectrum region.In this work,a 980 nm NIR all-inorganic perovskite NC LED is demonstrated,which is based on an efficient energy transfer from wide-bandgap materials(CsPbCl3 NCs)to ytterbium ions(Yb3+)as an NIR emitter doped in perovskite NCs.The optimized CsPbCl3 NC with 15 mol%Yb3+doping concentration has the strongest 980 nm photoluminescence(PL)peak,with a PL quantum yield of 63%.An inverted perovskite NC LED is fabricated with the structure of ITO/PEDOT:PSS/poly-TPD/CsPbCl3:15 mol%Yb3+NCs/TPBi/LiF/Al.The LED has an External Quantum Efficiency(EQE)of 0.2%,a Full Width at Half Maximum(FWHM)of 47 nm,and a maximum luminescence of 182 cd/m?.The introduction of Yb3+doping in perovskite NCs makes it possible to expand its working wavelength to near-infrared band for next-generation light sources and shows potential applications for optoelectronic integration.

关键词： perovskite nanocrystals rare-earth doping Light-Emitting Diode(LED) near-infrared optical interconnection

Effect of rare-earth doping on the dielectric property and polarization behavior of antiferroelectric sodium niobate-based ceramics

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Journal of Materiomics 2021年第2期7卷 339-346页

作者： Jiaming Ye Genshui Wang Xuefeng Chen Xianlin Dong Key Laboratory of Inorganic Functional Materials and Devices Shanghai Institute of CeramicsChinese Academy of Sciences1295 Dingxi RoadShanghai200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of Sciences1295 Dingxi RoadShanghai200050China

The lead-free 0.96NaNbO_(3)-0.04CaSnO_(3) ceramics with rare-earth dopants(La,Sm and Lu)(NCLn100x)were prepared and characterized.It is found that a certain amount of La substitution stabilizes the antiferroelectric(AFE)phase but alleviates the lattice distortion in the fresh samples.Re-entrant-like characteristics are observed in the temperature e dielectric constant curves with the room temperature P phase gradually replaced by a possible R phase.Relaxor-like hysteresis loops with suppressed hysteresis loss and remanent polarization were obtained at high La content,achieving a relatively high Wre of 2.1 J/cm^(3) at a low electric field(250 kV/cm).The relaxation behaviors of the ferroelectric(FE)domain measured by piezoresponse force microscopy suggest an even long characteristic relaxation time of field-induced FE phase,which is different from the situations of other AFE perovskites.Via an explanatory defected diatomic chain model,we propose that a much larger mass of substitutive ion than the origin one helps to induce low-frequency localized mode,which is believed to be in favor of the formation of polar nano-regions and hence strengthens the dynamic stability of FE phase during electric field loading.Our research provides a further understanding of the tuning strategy for enhancing the antiferroelectricity of the NaNbO_(3)-based system.

关键词： Ceramics rare-earth doping Phase transition Antiferroelectric

Effect of La^(3+)substitution on structural,microstructure,magnetic properties,and microwave absorbing ability of yttrium iron garnet

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Journal of rare earths 2023年第4期41卷 578-587页

作者： Sari Hasnah Dewi Ade Mulyawan Yosef Sarwanto Didin S.Winatapura Wisnu Ari Adi National Research and Innovation Agency Kawasan PuspiptekSerpongTangerang SelatanBanten15314Indonesia

Synthesis and characterization of lanthanum-doped yttrium iro n garnet(YIG)in the compositional se ries of Y_(3-x)La_(x)Fe_(5)O_(12)(x=0.0,0.1,0.3,and 0.5)were carried out.All compositions were made by using solid state reaction method with ball-milling technique.The phase formation,surface morphology,magnetic properties,and microwave absorbing ability of all compositions were characterized by using an X-ray diffractometer,a scanning electron microscope,a vibrating sample magnetometer,and a Vector network analyzer.The results reveal that all compositions are crystallized into Y_(3)Fe_(5)O_(12)phase(space group la-3d(230).It was observed that the lattice constant is increased from 1.2373 to 1.2421 nm with the increase of lanthanum substitution level from x=0.0-0.5.The crystallite size of Y_(3-x)La_(x)Fe_(5)O_(12)series calculated by Scherrer method is found to decrease from 78 nm in x=0.0-63 nm in x=0.5.The particle size distribution from the surface morphology image analysis is shifted to lower-range number with the increase of lanthanum substitution level from x=0.0 to 0.5.The substitution process also affects the lattice distortion in La-doped samples and changes the bond angles and bond lengths of the YIG structure.As the results,a linear correlation between the Fe'-O-Fe bond angle with magnetic properties parameters of saturation magnetization(M_(s))and remanence magnetization(M_(r))was studied.Due to the lanthanum substitution process,all La^(3+)-doped samples possess higher M_(s)and M_(r)values compared to the original composition.The results of Vector network analyzer show that the improvement of the M_(s)and M_(r)plays an important role in enhancing the microwave absorbing ability of the materials.The minimum RL changes from-8.22 dB(~85.22%microwave absorption)in x=0.0 to-14.21 dB(~96.25%microwave absorption)in x=0.5.The enhancement is mainly ascribed to the natural magnetic resonance loss and dipoIe-polarization loss due to the substitution process.The decreasing particle size also enhances the microwave

关键词： Yttrium iron garnet rare-earth doping Solid-state reaction Magnetic properties Structural properties Microwave absorbing ability

Electric field-induced photoluminescence quenching in Pr-doped BNT ceramics across the MPB region

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Journal of Materiomics 2022年第2期8卷 288-294页

作者： Mingze Sun Peng Li Juan Du Weifang Han Jigong Hao Kunyu Zhao Huarong Zeng Wei Li College of Materials Science and Engineering Liaocheng UniversityLiaocheng252059China Key Laboratory of Inorganic Functional Materials and Devices Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Material and Opto-Electronic Research Center University of Chinese Academy of SciencesBeijing100039China

Piezophotonics is a great interesting field of physics that has led to a number of important technologies,such as light source,smart sensors,and mechatronics.In this work,we reported Pr-doped(Bi_(0.5)Na_(0.5))TiO_(3)-based lead-free ceramics with strong red photoluminescence emission and large strain response(d_(33)^(*)=460 pm/V,S=0.32%).The PL emission can be quenched by decreasing the intensity by 93%after electrical polarization(E=50 kV/cm).The local structure and electric field-induced structural changes were systematically investigated to reveal the significant distinction in photoluminescence properties caused by electrical polarization.The results indicated that polarization treatment eliminates the structural inhomogeneities and establishes a long-range ferroelectric tetragonal and rhombohedral distortion.The crystal structure transformed irreversibly from a non-ergodic to a normal ferroelectric state.PL quenching originated from the decreased distortion of octahedral due to the transition from a non-ergodic state to a highly ordered symmetrical structure.Meanwhile,the enlarged domain structure contributed to the photoluminescence quenching effect.Our findings demonstrate that an electric field can be a robust tool for adjusting the photoluminescence property and provide insights into the rela-tionship between the structure and PL properties of BNT-based ceramics under an external stimulus.

关键词： BNT-based ceramics rare-earth doping Electric field-induced Photoluminescence quenching

Photocatalytic degradation of acid orange 7 in aqueous solution with La^(3+)-doped TiO_2 photocatalysts

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rare Metals 2005年第4期24卷 358-362页

作者： XIA Changbin ZHOU Yi LI Xun ZENG Jing XU Ruiyin School of Chemistry and Chemical Technology Hunan University of Science and Technology Xiangtan 411201 China Department of Chemistry and Environmental Engineering Changsha University of Science and Technology Changsha 410077 China Civil and Environmental Engineering School University of Science and Technology Beijing Beijing 100083 China

Nanocrystalline La^3＋-doped TiO2 of 20-30 nm in size was prepared by a sol-gel technique. The photocatalytic activities of the samples were evaluated by the degradation of harmful acid orange 7（AO7） azo-dye in aqueous solution. The effects of La^3＋ ion implantation on the photocatalytic activity of TiO2 were also discussed. The results show that the La^3＋ content plays an essential role in affecting the photocatalytic activity of the La^3＋-doped TiO2 and the optimum content of La^3＋-doped is 1.0 wt.%. The photocatalytic activity of the samples with La^3＋-doped TiO2 is higher than that of pure TiO2 in the treatment of AO7 wastewater. The photodegradation effect of AO7 effluent is the best by means of La^3＋-doped TiO2 with 1.0% La^3＋.

关键词： photocatalytic degradation titanium oxide rare-earth doping azo-dyes

Effect of cerium on structure,magnetism and magnetostriction of Fe_(81)Ga_(19) alloy

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Journal of rare earths 2018年第7期36卷 721-724页

作者： Tingdong Zhou Yu Zhang Daocheng Luan Qing Cai School of Materials Science and Engineering Xihua University

FeGa alloy is a new kind of magnetostrictive material, and rare-earth cerium can improve its magnetostrictive property.（Fe（81）Ga（19））（100-x）Cex（x = 0, 0.3 at%, 0.7 at%, 1 at%） samples were prepared by doping cerium in Fe（81）Ga（19） alloy. Their microstructures and phases were studied, and valence electronic structures were investigated. Electromagnetic parameters, such as coercivity, saturation magnetization,remnant magnetization and saturation magnetostrictive coefficients（λs） of every sample were measured.Cerium atoms are distributed at grain boundaries, and the Ce-doped alloys remain the A2 structure of FeGa alloy. When x is 0.7, the value of saturation magnetism is 217.08 emu/g, which is the maximum in the Ce-doped samples. The equivalent half length of single bond is the maximum also, and reaches to0.11380 nm. At the same time, the number of covalent electrons is 3.5672, and is the minimum of the Cedoped samples. Its As is the largest in the four samples. The change of As results in the change of equivalent half length of single bond in Ce-doped alloy.

关键词： FeGaCe alloy Valence electronic structure Electromagnetic parameter Saturation magnetostrictive coefficient rare-earth doping

The magnetic properties of permanent Strontium Ferrite doped with rare-earth by Chemical co-precipitation method

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The magnetic properties of permanent Strontium Ferrite doped...