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Rare-earth and transition metal ion single-/co-doped double-perovskite tantalate phosphors: Validation of suitability for versatile applications

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Journal of Advanced Ceramics 2023年第5期12卷 954-971页

作者： Yongbin Hua jae su yu Li Li Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityYongin-si 17104Republic of Korea School of Science Chongqing University of Posts and TelecommunicationsChongqing 400065China

Novel rare-earth (RE;e.g., europium (Eu^(3+)), samarium (Sm^(3+)), and praseodymium (Pr^(3+))) and transition metal (TM^(4+);e.g., manganese (Mn^(4+))) ion single-/co-doped double-perovskite Ca2InTaO6 (CITO) phosphors were prepared and investigated with respect to their crystal structure and photoluminescence (PL) properties. Among them, the CITO:Eu^(3+) phosphors were found to exhibit an ultra-high internal PL quantum yield (89.1%) and good thermal stability (78.7% at 423 K relative to the initial value at 303 K). As such, the corresponding packaged white light-emitting diode (LED) was able to display a remarkable color rendering index (CRI;= 91.51@10 mA). Besides, the potential in applications of anti-counterfeiting fields and a novel LED structure based on flexible phosphor-converted films was also studied. Moreover, due to their different thermal quenching, trivalent lanthanide (Ln^(3+))/Mn^(4+) co-doped CITO phosphors were designed for optical thermometry based on the luminescence intensity ratio (LIR) between different 4f transitions of various Ln^(3+) ions and ^(2)Eg → ^(4)A_(2g) (Mn^(4+)) transition. Particularly, the LIR between the ^(4)G_(5/2) → ^(6)H_(9/2) and ^(2)Eg → ^(4)A_(2g) peaks of the CITO activated with 5 mol% Sm^(3+) and 0.3 mol% Mn^(4+) exhibited the most excellent relative sensitivity (Sr;= 3.80 %·K^(−1)) with beneficial temperature uncertainty of 0.0648 K. Overall, these results are of significance to offer valuable databases for constructing multifunctional high-performance optical platforms using single-/co-doped double-perovskite tantalates.

关键词： phosphors quantum yields(QYs) light-emitting diodes(LEDs) thermometry anti-counterfeiting

Triboelectric nanogenerators with gold-thin-film-coated conductive textile as floating electrode for scavenging wind energy

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Nano Research 2018年第1期11卷 101-113页

作者： Bhaskar Dudem Dong Hyun Kim jae su yu Department of Electronic Engineering Kyung Hee University 1732 Deogyeong-daero Giheung-gu Yongin-si Gyeonggi-do 446-701Republic of Korea

We report triboelectric nanogenerators （TENGs） composed of a flexible and cost-effective gold-coated conductive textile （CT） to convert wind energy into electricity. The Au-coated CT is employed because of its high surface roughness resulting from Au nanodots distributed on microsized fibers. Thus, the Au-coated CT with nano/microarchitecture plays an important role in enhancing the effective contact area as well as the output performance of the TENG. Moreover, the surface roughness of the Au-coated CT is controlled by adjusting the Au thermal deposition time or tailoring the diameter of the Au nanodots. At an applied wind speed of 10 m.s-1, a wind-based TENG （W-TENG） with dimensions of 75 mm × 12 mm ×25 mm produces an open-circuit voltage （Voc） of - 39 V and a short-circuit current （Isc） of - 3 A by using the airflow-induced vibrations of an optimized Au-coated CT between two flat polydimethylsiloxane （PDMS） layers. To further specify the device performance, the electric output of the W-TENG is analyzed by varying several parameters such as the distance between the PDMS layer and Au-coated CT, applied wind speed, external load resistance, and surface roughness of the PDMS layers. Introducing an inverse micropyramid architecture on the PDMS layers further improves the output performance of the W-TENG, which exhibits the highest Voc （- 49 V） and Isc （- 5μA） values at an applied wind speed of 6.8 m.s-1. Additionally, the reliability of the W-TENG is also tested by measuring its output current during long-term cyclic operation. Furthermore, the rectified output signals observed by the W-TENG device are used as a direct power source to light 45 green commercial light-emitting diodes connected in series and also to charge capacitors （100 and 4.7μF）. Finally, the output performance of the W-TENG device in an actual windy situation is also investigated.

关键词： triboelectric nanogenerators Au-coated conductivetextile polydimethylsiloxanelayer wind energy

Entire onion source-derived redox porous carbon electrodes towards efficient quasi-solid-state solar charged hybrid supercapacitor

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Journal of Materials Science & Technology 2022年第30期125卷 118-127页

作者： Edugulla Girija Shankar Amit Kumar Das jae su yu Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityGyeonggi-do 17104Republic of Korea

Biomass-derived electrodes inherently containing redox-active species have gained extensive attention recently due to their availability,eco-friendliness,sustainability,and low *** report novel binder-free faradic surface redox onion-derived carbon positive electrode with nano regime particles by hydrothermal synthesis and Na^(+)and Cl^(−)ions diffused porous carbon negative electrode via a carbonization ***-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed the presence of oxidized sulfur and(N-6)pyridinic N-based redox groups inherently present in the as-prepared *** electrochemical analysis of the positive electrode revealed its faradic redox type of energy storage mechanism with an excellent specific capacitance of 1805 Fg^(-1) at the current density of 3 Ag^(-1) as well as appreciable long-term cycling stability(76.8%retention after 10000 charge-discharge cycles).Meanwhile,the negative electrode exhibited a maximum specific capacitance of 373 Fg^(-1) at 1 Ag^(-1) with outstanding long-term cycling stability(100.7%retention after 10000 cycles).The fabricated polyvinyl alcohol-potassium hydroxide gel electrolyte-based quasi-solid-state hybrid supercapacitor(QHSC)delivered excellent energy density and power density of 19.94 Wh kg^(-1) and 374.99 W kg^(-1),respectively with an ultralong cyclic life(102.3% retention)over 10000 ***,the QHSC was connected to a solar panel to store renewable *** charged QHSC effectively powered a speedometer,enlightening its potential application in advanced sustainable energy storage systems.

关键词： Binder-free Biomass Green source Hybrid supercapacitor Solar energy storage Faradic redox type

Cerium vanadate/carbon nanotube hybrid composite nanostructures as a high-performance anode material for lithium-ion batteries

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Journal of Energy Chemistry 2021年第7期30卷 25-32页

作者： D.Narsimulu Ashok Kumar Kakarla jae su yu Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do 17104Republic of Korea

The pristine CeVO_(4) and CeVO_(4)/CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath *** the X-ray diffraction results,the formation of tetragonal CeVO_(4) with an additional minor phase of V_(2)O_(5) was *** investigated as an anode material for lithium(Li)-ion batteries,the CeVO_(4)/CNT hybrid composite nanostructure(HCNS) electrode demonstrated improved Li storage performance over the pristine CeVO_(4).The Li insertion/de-insertion electrochemical reaction with the CeVO_(4) was analyzed on the basis of cyclic voltammetry *** cyclic voltammetry analysis revealed that the three-step reduction of V^(5+) to V^(3+), V^(3+) to V^(2+), and V^(2+) to V+ processes is involved and among them,only V^(5+) to V^(3+) is reversible during the Li-ion insertion into CeVO_(4).The CeVO_(4)/CNT HCNS electrode exhibited a discharge capacity as high as 443 mA h g^(-1)(capacity retention of 96.3%) over 200 cycles at 100 mA g^(-1), whereas the pristine CeVO_(4) is limited to 138 mA h g^(-1)(capacity retention of 48%).Even at a high current density of 500 mA g^(-1), the CeVO_(4)/CNT HCNS electrode delivered an excellent reversible capacity of 586.82 mA h g^(-1) after 1200 cycles.

关键词： Oil-bath synthesis CeVO_(4)/CNT hybrid composite nanostructure Anode Lithium-ion batteries

surface-engineered binder-free PEDOT shielded nickel magnesium selenide nanosheet arrays electrode for ultralong-life flexible quasi-solid-state hybrid supercapacitors

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Journal of Magnesium and Alloys 2023年第5期11卷 1802-1814页

Together with the development of high-performance advanced electronics,flexible supercapacitors(SCs)with tailored nanostructures have great *** deposited nanosheet arrays of nickel magnesium selenide(NixMg3-xSe4,NMgS)with high capacitance provide high potentials as a positive electrode in flexible *** further enhance their electrochemical properties and long-term cycling stability,a promising strategy of surface engineering with conducting polymer poly(3,4-ethylenedioxythiophene)(PEDOT)is *** present work proposes the construction of PEDOT shielded NMgS(P@NMgS-2)on a flexible carbon cloth substrate via a hierarchical electrodeposition *** from the synergistic effect,the P@NMgS-2 exhibits an excellent areal capacitance value of 1440 mF cm^(-2)at 4 mA cm^(-2).A novel shape-adaptable polymer gel electrolyte-assisted flexible quasi-solid-state hybrid SC(FQHSC)device constructed with P@NMgS-2 as a positive electrode and activated carbon as a negative electrode demonstrates the maximum power and energy density values of 14.13 mW cm^(-2)and 0.18 mWh cm^(-2),respectively,followed by outstanding cycling stability(∼100%capacitance retention over 50,000 cycles).Furthermore,the FQHSC device successfully powered electronic devices with no serious degradation upon bending and twisting for wearable electronic applications.

关键词： Hierarchical electrodeposition P@NMgS-2 hybrid Synergistic effect Shape-adaptable electrolyte Flexible quasi-solid-state supercapacitors

Double-excited states of charge transfer band and 4f-4f in single-phase K_(3)Gd(VO_(4))_(2):Tb^(3+)/Sm^(3+) phosphors with superior sensing sensitivity for potential luminescent thermometers

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Journal of Materials Science & Technology 2021年第32期91卷 148-159页

作者： Yongbin Hua jae suyu Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityYongin-siGyeonggi-do 17104Republic of Korea

Temperature is one of the fundamental parameters for thermodynamics and its accurate detection is *** novel strategy of luminescent materials based on the fluorescence intensity ratio technique has been promised for thermometers in more practical environments to overcome the drawbacks of conventional thermometers in ***,the novel single-phase K_(3) Gd(VO_(4))_(2):Tb^(3+)/Sm^(3+) phosphors were successfully prepared,and the ~4 G_(5/2)→ ~6 H9/2(Sm^(3+)) and ~5 D_(4) → ~7 F_(5)(Tb^(3+)) transitions could be promised for luminescent ***,under the double-excited states of charge transfer band(CTB,317 nm) and 4 f-4 f(478 nm) excitations,the K_(3) Gd(VO_(4))_(2):Tb^(3+)/Sm^(3+) phosphors exhibited different concentration quenching mechanisms in energy transfer processes and also showed superior absolute sensing sensitivity(S_a) and relative sensing sensitivity(S_r).Especially,the maximum S_a and S_r values reached up to 0.568 K^(-1) and 11.24% K^(-1),respectively and the temperature resolution of the KGV:0.2 Tb^(3+)/0.01 Sm^(3+)phosphor was higher than 0.004 K under the excitation wavelength of CTB(317 nm),indicating that the double-excited states in the single-phase KGV:Tb^(3+)/Sm^(3+) phosphors with superior sensing sensitivity could be a novel candidate for potential optical thermometers.

关键词： Double-excited lines FIR technique Energy transfer Sensing sensitivity

Multicomponent mixed metallic hierarchical ZnNi@Ni@PEDOT arrayed structures as advanced electrode for high-performance hybrid electrochemical cells

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Journal of Energy Chemistry 2023年第9期84卷 448-458页

作者： Anki Reddy Mule Bhimanaboina Ramulu Shaik Junied Arbaz jae su yu Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do 17104Republic of Korea

Engineering multicomponent nanomaterials as an electrode with rationalized ordered structures is a promising strategy for fulfilling the high-energy storage needs of supercapacitors(SCs).Even now,the fundamental barrier to utilizing hydroxides/hydroxyl carbonates is their poor electrochemical performance,resulting from the significantly poor electrical conductivity and sluggish charge storage ***,a multilayered structural approach is primarily and successfully used to construct electrodes as one of the efficient *** method has made it possible to develop well-ordered nanostructured electrodes with good performance by taking advantage of tunable approach ***,we report the design of multilayered heterostructure porous zinc-nickel nanosheets@nickel flakes hydroxyl carbonates and/or hydroxides integrated with conductive PEDOT fibrous network(i.e.,ZnNi@Ni@PEDOT) via facile synthesis *** combined hybrid electrode acquires the features of high electrical conductivity from one part and various valance states from another one to develop a well-organized nanosheet/flake/fibrous-like heterostructure with decent mechanical strength,creating robust synergistic ***,the designed binder-free ZnNi@Ni@PEDOT electrode delivers a high areal capacity value of 1050.1 μA h cm^(-2) at 3 mA cm^(-2) with good cycling durability,significantly outperforming other individual ***,its feasibility is also tested by constructing a hybrid electrochemical cell(HEC).The assembled HEC exhibits a high areal capacity value of 783.8 μA h cm^(-2) at5 mA cm^(-2).and even at a high current density of 100 mA cm^(-2)(484.6 μA h cm^(-2)),the device still retains a rate capability of 61,82%,Also,the HEC shows maximum energy and power densities of0.595 mW h cm^(-2) and 77.23 mW cm^(-2),respectively,along with good cycling *** obtained energy storage capabilities effectively power various electronic *** results provide a v

关键词： Mixed metal Hydroxyl carbonates/hydroxides Layer-by-layer design Fibrous PEDOT network Electrochemical performance Hybrid electrochemical cell

Highly flexible conductive fabrics with hierarchically nanostructured amorphous nickel tungsten tetraoxide for enhanced electrochemical energy storage

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Nano Research 2015年第12期8卷 3749-3763页

作者： Goli Nagaraju Ramesh Kakarla sung Min Cha jae su yu Department of Electronics and Radio Engineering Institute for Wearable Convergence Electronics Kyung Hee University 1 Seocheon-dong Giheung-gu Yongin-si Gyeonggi-do 446-701 Republic of Korea Department of Environmental Science and Engineering Kyung Hee University 1Seocheon-dong Giheung-gu Yongin-si Gyeonggido 446-701 Republic of Korea

Amorphous nickel tungsten tetraoxide （NiWO4） nanostructures （NSs） were successfully synthesized on a flexible conductive fabric （CF） using a facile one- step electrochemical deposition （ED） method. With an applied external cathodic voltage （-1.8 V for 15 min）, the amorphous NiWO4 NSs with burl-like morphologies adhered well on the seed-coated CF substrate. The burMike amorphous NiWO4 NSs on CF （NiWO4 NSs/CF） are employed as a flexible and binder-free electrode for pseudocapacitors, which exhibit remarkable electrochemical properties with high specific capacitance （1,190.2 F/g at 2 A/g）, excellent cyclic stability （92% at 10 A/g）, and good rate capability （765.7 F/g at 20 A/g） in 1 M KOH electrolyte solution. The superior electrochemical properties can be ascribed to the hierarchical structure and large specific surface area of the burl-like amorphous NiWO4 NSs/CF. This cost-effective facile method for the synthesis of metal tungsten tetraoxide nanomaterials on a flexible CF could be promising for advanced electronic and energy storage device applications.

关键词： amorphous NiWO4 nanostructures conductive fabrics electrochemical deposition electrochemical energystorage properties

Ag-integrated mixed metallic Co-Fe-Ni-Mn hydroxide composite as advanced electrode for high-performance hybrid supercapacitors

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Journal of Energy Chemistry 2024年第1期88卷 579-591,I0013页

作者： Anki Reddy Mule Bhimanaboina Ramulu Shaik Junied Arbaz Anand Kurakula jae su yu Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityYongin-siGyeonggi-do 17104Republic of Korea

Direct growth of redox-active noble metals and rational design of multifunctional electrochemical active materials play crucial roles in developing novel electrode materials for energy storage *** this regard,silver(Ag)has attracted great attention in the design of efficient *** by the house/building process,which means electing the right land,it lays a strong foundation and building essential columns for a complex ***,we report the construction of multifaceted heterostructure cobalt-iron hydroxide(CFOH)nanowires(NWs)@nickel cobalt manganese hydroxides and/or hydrate(NCMOH)nanosheets(NSs)on the Ag-deposited nickel foam and carbon cloth(i.e.,Ag/NF and Ag/CC)***,the formation and charge storage mechanism of Ag are described,and these contribute to good conductive and redox chemistry *** switching architectural integrity of metal and redox materials on metallic frames may significantly boost charge storage and rate performance with noticeable drop in *** as-fabricated Ag@CFOH@NCMOH/NF electrode delivered superior areal capacity value of 2081.9μA h cm^(-2)at 5 mA cm^(-2).Moreover,as-assembled hybrid cell based on NF(HC/NF)device exhibited remarkable areal capacity value of 1.82 mA h cm^(-2)at 5 mA cm^(-2)with excellent rate capability of 74.77%even at 70 mA cm^(-2)Furthermore,HC/NF device achieved maximum energy and power densities of 1.39 mW h cm^(-2)and 42.35 mW cm^(-2),*** verify practical applicability,both devices were also tested to serve as a self-charging station for various portable electronic devices.

关键词： Current collectors Redox-active silver Transition metal-hydroxides Electrochemical performance Hybrid supercapacitor