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Patterning of Metal Halide Perovskite Thin Films and Functional Layers for Optoelectronic Applications
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作者 Jin‑Wook Lee Seong Min Kang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第10期494-513,共20页
In recent years,metal halide perovskites have received significant attention as materials for next-generation optoelectronic devices owing to their excellent optoelectronic properties.The unprecedented rapid evolution... In recent years,metal halide perovskites have received significant attention as materials for next-generation optoelectronic devices owing to their excellent optoelectronic properties.The unprecedented rapid evolution in the device performance has been achieved by gaining an advanced understanding of the composition,crystal growth,and defect engineering of perovskites.As device performances approach their theoretical limits,effective optical management becomes essential for achieving higher efficiency.In this review,we discuss the status and perspectives of nano to micron-scale patterning methods for the optical management of perovskite optoelectronic devices.We initially discuss the importance of effective light harvesting and light outcoupling via optical management.Subsequently,the recent progress in various patterning/texturing techniques applied to perovskite optoelectronic devices is summarized by categorizing them into top-down and bottom-up methods.Finally,we discuss the perspectives of advanced patterning/texturing technologies for the development and commercialization of perovskite optoelectronic devices. 展开更多
关键词 Perovskites OPTOELECTRONICS Light outcoupling Light harvesting PATTERNING
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Occurrence of anionic redox with absence of full oxidation to Ru^(5+) in high-energy P2-type layered oxide cathode
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作者 Jinho Ahn Hyunyoung Park +10 位作者 Wonseok Ko Yongseok Lee Jungmin Kang Seokjin Lee Sangyeop Lee Eunji Sim Kyuwook Ihm Jihyun Hong Jung-Keun Yoo Kyojin Ku Jongsoon Kim 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第9期153-161,共9页
The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the a... The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the anionic reaction of O^(2-)/O~-to occur during Na^(+) de/intercalation.However,here,we report that the anionic redox can occur in Ru-based layered-oxide-cathodes before full oxidation of Ru^(4+)/Ru^(5+).Combining studies using first-principles calculation and experimental techniques reveals that further Na^(+) deintercalation from P2-Na_(0.33)[Mg_(0.33)Ru_(0.67)]O_(2) is based on anionic oxidation after 0.33 mol Na^(+) deintercalation from P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) with cationic oxidation of Ru^(4+)/Ru^(4.5+).Especially,it is revealed that the only oxygen neighboring 2Mg/1 Ru can participate in the anionic redox during Na^(+) de/intercalation,which implies that the Na-O-Mg arrangement in the P2-Na_(0.33)[M9_(0.33)Ru_(0.67)]O_(2) structure can dramatically lower the thermodynamic stability of the anionic redox than that of cationic redox.Through the O anionic and Ru cationic reaction,P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) exhibits not only a large specific capacity of~172 mA h g^(-1) but also excellent power-capability via facile Na^(+) diffusion and reversible structural change during charge/discharge.These findings suggest a novel strategy that can increase the activity of anionic redox by modulating the local environment around oxygen to develop high-energy-density cathode materials for NIBs. 展开更多
关键词 Na-ion batteries P2-type cathode Anionic redox Local environment First-principles calculation
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High Na-ion conductivity andmechanical integrity of anion-exchanged polymeric hydrogel electrolytes for flexible sodium ion hybrid energy storage
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作者 JungWoo Hong Harpalsinh H.Rana +10 位作者 Jeong Hee Park Jun Su Kim Sang Joon Lee Gun Jang Tae Hoon Kang Kang Ho Shin Sang Ha Baek Wooseok Yang Kwang Ho Kim Ju-Hyuk Lee Ho Seok Park 《SusMat》 SCIE EI 2024年第1期140-153,共14页
The polymeric gel electrolytes are attractive owing to their higher ionic conductivities than those of dry polymer electrolytes and lowered water activity for enlarged potential window.However,the ionic conductivity a... The polymeric gel electrolytes are attractive owing to their higher ionic conductivities than those of dry polymer electrolytes and lowered water activity for enlarged potential window.However,the ionic conductivity and mechanical strength of the Na-ion conducting polymeric gel electrolytes are limited by below 20 mS cm−1 and 2.2 MPa.Herein,we demonstrate Na-ion conducting and flexible polymeric hydrogel electrolytes of the chemically coupled poly(diallyldimethylammonium chloride)-dextrin-N,N′-methylene-bisacrylamide film immersed in NaClO_(4) solution(ex-DDA-Dex+NaClO_(4))for flexible sodium-ion hybrid capacitors(f-NIHC).In particular,the anion exchange reaction and synergistic interaction of ex-DDA-Dex with the optimum ClO_(4)−enable to greatly improve the ionic conductivity up to 27.63 mS cm−1 at 25◦C and electrochemical stability window up to 2.6 V,whereas the double networking structure leads to achieve both the mechanical strength(7.48 MPa)and softness of hydrogel electrolytes.Therefore,the f-NIHCs with the ex-DDA-Dex+NaClO_(4) achieved high specific and high-rate capacities of 192.04 F g^(−1)at 500 mA g^(−1)and 116.06 F g^(−1)at 10000 mA g^(−1),respectively,delivering a large energy density of 120.03Wh kg^(−1)at 906Wkg^(−1)and long cyclability of 70%over 500 cycles as well as demonstrating functional operation under mechanical stresses. 展开更多
关键词 anion exchange chemistry flexible energy storage hybrid energy storage hydrogel electrolytes renewable electrolytes sodium storage
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Interface engineering of an electrospun nanofiber-based composite cathode for intermediate-temperature solid oxide fuel cells
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作者 Seo Ju Kim Deokyoon Woo +3 位作者 Donguk Kim Tae Kyeong Lee Jaeyeob Lee Wonyoung Lee 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2023年第1期345-353,共9页
Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface bet... Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface between the cathode and electrolyte is important for facilitating ORR kinetics and hence improving the electrochemical performance.We developed the yttria-stabilized zirconia(YSZ)nanofiber(NF)-based composite cathode,where the oxygen vacancy concentration is controlled by varying the dopant cation(Y2O3)ratio in the YSZ NFs.The composite cathode with the optimized oxygen vacancy concentration exhibits maximum power densities of 2.66 and 1.51 W cm^(−2)at 700 and 600℃,respectively,with excellent thermal stability at 700℃ over 500 h under 1.0 A cm^(−2).Electrochemical impedance spectroscopy and distribution of relaxation time analysis revealed that the high oxygen vacancy concentration in the NF-based scaffold facilitates the charge transfer and incorporation reaction occurred at the interfaces between the cathode and electrolyte.Our results demonstrate the high feasibility and potential of interface engineering for achieving IT-SOFCs with higher performance and stability. 展开更多
关键词 solid oxide fuel cells NANOFIBER INFILTRATION oxygen reduction reactions oxygen vacancy
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Unexpected Li displacement and suppressed phase transition enabling highly stabilized oxygen redox in P3-type Na layered oxide cathode
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作者 Myungeun Choi Hobin Ahn +9 位作者 Hyunyoung Park Yongseok Lee Jinho Ahn Bonyoung Ku Junseong Kim Wonseok Ko Jungmin Kang Jung-Keun Yoo Duho Kim Jongsoon Kim 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第10期144-153,I0006,共11页
Oxygen redox is considered a new paradigm for increasing the practical capacity and energy density of the layered oxide cathodes for Na-ion batteries. However, severe local structural changes and phase transitions dur... Oxygen redox is considered a new paradigm for increasing the practical capacity and energy density of the layered oxide cathodes for Na-ion batteries. However, severe local structural changes and phase transitions during anionic redox reactions lead to poor electrochemical performance with sluggish kinetics.Here, we propose a synergy of Li-Cu cations in harnessing the full potential of oxygen redox, through Li displacement and suppressed phase transition in P3-type layered oxide cathode. P3-type Na_(0.7)[Li_(0.1)Cu_(0.2)Mn_(0.7)]O_(2) cathode delivers a large specific capacity of ~212 mA h g^(-1)at 15 mA g^(-1). The discharge capacity is maintained up to ~90% of the initial capacity after 100 cycles, with stable occurrence of the oxygen redox in the high-voltage region. Through advanced experimental analyses and first-principles calculations, it is confirmed that a stepwise redox reaction based on Cu and O ions occurs for the charge-compensation mechanism upon charging. Based on a concrete understanding of the reaction mechanism, the Li displacement by the synergy of Li-Cu cations plays a crucial role in suppressing the structural change of the P3-type layered material under the oxygen redox reaction, and it is expected to be an effective strategy for stabilizing the oxygen redox in the layered oxides of Na-ion batteries. 展开更多
关键词 Layered oxide cathode Oxygen redox reaction Structural stability Li displacement No phase transition
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Single-Phase Ternary Compounds with a Disordered Lattice and Liquid Metal Phase for High-Performance Li-Ion Battery Anodes
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作者 Yanhong Li Lei Zhang +8 位作者 Hung-Yu Yen Yucun Zhou Gun Jang Songliu Yuan Jeng-Han Wang Peixun Xiong Meilin Liu Ho Seok Park Wenwu Li 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第5期36-50,共15页
Si is considered as the promising anode materials for lithium-ion batteries(LIBs)owing to their high capacities of 4200 mAh g-1and natural abundancy.However,severe electrode pulverization and poor electronic and Li-io... Si is considered as the promising anode materials for lithium-ion batteries(LIBs)owing to their high capacities of 4200 mAh g-1and natural abundancy.However,severe electrode pulverization and poor electronic and Li-ionic conductivities hinder their practical applications.To resolve the afore-mentioned problems,we first demonstrate a cation-mixed disordered lattice and unique Li storage mechanism of single-phase ternary GaSiP_(2)compound,where the liquid metallic Ga and highly reactive P are incorporated into Si through a ball milling method.As confirmed by experimental and theoretical analyses,the introduced Ga and P enables to achieve the stronger resistance against volume variation and metallic conductivity,respectively,while the cation-mixed lattice provides the faster Li-ionic diffusion capability than those of the parent GaP and Si phases.The resulting GaSiP_(2)electrodes delivered the high specific capacity of 1615 mAh g-1and high initial Coulombic efficiency of 91%,while the graphite-modified GaSiP_(2)(GaSiP_(2)@C)achieved 83%of capacity retention after 900 cycles and high-rate capacity of 800 at 10,000 mA g-1.Furthermore,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)//Ga SiP_(2)@C full cells achieved the high specific capacity of 1049 mAh g-1after 100 cycles,paving a way for the rational design of high-performance LIB anode materials. 展开更多
关键词 Multinary compounds Liquid metal GaSiP_(2) Disordered lattice Li-ion batteries
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MXene ink hosting zinc anode for high performance aqueous zinc metal batteries
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作者 Jae Min Park Milan Jana +9 位作者 Sang Ha Baek Taehun Kang Peixun Xiong Jeong Hee Park Jun Soo Kim Ali Shayesteh Zeraati Mikhail Shekhirev Paul V.Braun Yury Gogotsi Ho Seok Park 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第1期187-194,I0005,共9页
Despite the safety,low cost,and high theoretical capacity(820 mA h g^(-1))of Zn metal anodes,the practical application of aqueous Zn metal batteries remains a critical challenge due to the Zn dendrite growth,corrosion... Despite the safety,low cost,and high theoretical capacity(820 mA h g^(-1))of Zn metal anodes,the practical application of aqueous Zn metal batteries remains a critical challenge due to the Zn dendrite growth,corrosion,and hydrogen evolution reaction.Herein,we demonstrate the MXene ink hosting Zn metal anodes(MX@Zn)for high-performance and patternable Zn metal full batteries.The as-designed MX@Zn electrode is more facile and reversible than bare Zn and CC@Zn,as verified by better cyclic stability and lower overpotentials of symmetric cells with the plating capacity of 0.05 mA h cm^(-2)at 0.1 m A cm^(-2)and of 1 m A h cm^(-2)at 1 m A cm^(-2).The MX@Zn|MnO_(2)full cells deliver a high specific capacity of 281.9 m A h g^(-1),91.5%of the theoretical capacity,achieving 50%capacity retention from 60 mA g^(-1)to 300 mA g^(-1)and 79.7%of initial capacity after 200 cycles.Moreover,the patterned devices based on the MX@Zn electrode achieve high energy and power densities of 348.57 Wh kg^(-1)and 1556 W kg^(-1),respectively,along with a capacity retention of 64%and Coulombic efficiency of 99%over 500 cycles.The high performance of MX@Zn is attributed to the high electrical conductivity and hydrophilicity of MXene and rapid ion diffusion through the 3D interconnected porous channels. 展开更多
关键词 MXene ink Zinc anode Metal batteries PATTERNING ELECTRODEPOSITION
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Towards sustainability with self-healing and recyclable perovskite solar cells
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作者 Hui Zhang Nam-Gyu Park 《eScience》 2022年第6期567-572,共6页
Lead halide perovskite solar cells(PSCs)have been considered one of the most promising candidates for future energy supply,whereas just solar cell does not guarantee sustainability.Owing to the ionic nature and consti... Lead halide perovskite solar cells(PSCs)have been considered one of the most promising candidates for future energy supply,whereas just solar cell does not guarantee sustainability.Owing to the ionic nature and constituent heavy metals,perovskite materials are prone to decay under operating conditions and pose a threat to ecosystems and human health,seriously restricting their practical deployment.Herein,we briefly review safe-by-design strategies to heal failed PSCs and thereby extend their operational lifetime and to recycle lead perovskites at the end of their lifespan for cyclic utilization.From the point of view of processability,scalability,and universality,we recommend future approaches for the further development of PSCs towards sustainable photovoltaics,taking into consideration materials selection,device design,and process optimization. 展开更多
关键词 SELF-HEALING RECYCLING Perovskite solar cells SUSTAINABILITY Photovoltaics
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Wearable EEG electronics for a Brain–AI Closed-Loop System to enhance autonomous machine decision-making
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作者 Joo Hwan Shin Junmo Kwon +5 位作者 Jong Uk Kim Hyewon Ryu Jehyung Ok SJoon Kwon Hyunjin Park Tae-il Kim 《npj Flexible Electronics》 SCIE 2022年第1期296-307,共12页
Human nonverbal communication tools are very ambiguous and difficult to transfer to machines or artificial intelligence(AI).If the AI understands the mental state behind a user’s decision,it can learn more appropriat... Human nonverbal communication tools are very ambiguous and difficult to transfer to machines or artificial intelligence(AI).If the AI understands the mental state behind a user’s decision,it can learn more appropriate decisions even in unclear situations.We introduce the Brain-AI Closed-Loop System(BACLoS),a wireless interaction platform that enables human brain wave analysis and transfers results to AI to verify and enhance AI decision-making.We developed a wireless earbud-like electroencephalography(EEG)measurement device,combined with tattoo-like electrodes and connectors,which enables continuous recording of high-quality EEG signals,especially the error-related potential(ErrP).The sensor measures the ErrP signals,which reflects the human cognitive consequences of an unpredicted machine response.The AI corrects or reinforces decisions depending on the presence or absence of the ErrP signals,which is determined by deep learning classification of the received EEG data.We demonstrate the BACLoS for AIbased machines,including autonomous driving vehicles,maze solvers,and assistant interfaces. 展开更多
关键词 AUTONOMOUS EEG enable
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