Sow Chorng Haur
Degree: PhD
Position: Vice Dean
Affiliation: NUS – Department of Physics
Research Type: Experiment
Office: S12-02-13
Email: physowch@nus.edu.sg
Contact: (65) 6516 2957
Website: http://www.physics.nus.edu.sg/staff/sowch.html
CA2DM Publications:
2024 |
Lai, Wenhui; Lee, Jong Hak; Shi, Lu; Liu, Yuqing; Pu, Yanhui; Ong, Yong Kang; Limpo, Carlos; Xiong, Ting; Rao, Yifan; Sow, Chorng Haur; Ozyilmaz, Barbaros High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries Journal Article JOURNAL OF ENERGY CHEMISTRY, 93 , pp. 253-263, 2024, ISSN: 2095-4956. @article{ISI:001203104900001, title = {High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries}, author = {Wenhui Lai and Jong Hak Lee and Lu Shi and Yuqing Liu and Yanhui Pu and Yong Kang Ong and Carlos Limpo and Ting Xiong and Yifan Rao and Chorng Haur Sow and Barbaros Ozyilmaz}, doi = {10.1016/j.jechem.2024.02.021}, times_cited = {0}, issn = {2095-4956}, year = {2024}, date = {2024-06-01}, journal = {JOURNAL OF ENERGY CHEMISTRY}, volume = {93}, pages = {253-263}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved. |
2023 |
Zhang, Hanwen; Poh, Eng Tuan; Lim, Sharon Xiaodai; Zhang, Yimin; Qin, Hongye; Xie, Haonan; He, Chunnian; Sow, Chorng Haur In situ strain-induced phase transition and defect engineering in CVD-synthesized atomically thin MoS2 Journal Article 2D MATERIALS, 10 (3), 2023, ISSN: 2053-1583. @article{ISI:000994586300001, title = {\textit{In situ} strain-induced phase transition and defect engineering in CVD-synthesized atomically thin MoS_{2}}, author = {Hanwen Zhang and Eng Tuan Poh and Sharon Xiaodai Lim and Yimin Zhang and Hongye Qin and Haonan Xie and Chunnian He and Chorng Haur Sow}, doi = {10.1088/2053-1583/acd0be}, times_cited = {0}, issn = {2053-1583}, year = {2023}, date = {2023-07-01}, journal = {2D MATERIALS}, volume = {10}, number = {3}, publisher = {IOP Publishing Ltd}, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, abstract = {Alkali metal halides have recently received great attention as additives in the chemical vapor deposition (CVD) process to promote the growth of transition metal dichalcogenides (TMDs). However, the multi-faceted role of these halide salts in modulating the properties and quality of TMD monolayers remains mechanistically unclear. In this study, by introducing excessive gaseous sodium chloride (NaCl) into the CVD system, we demonstrate that preferential NaCl deposition along the monolayer edges causes large in situ strain that can invoke localized domains of high defect density and 2H to 1T phase transition. High-resolution scanning transmission electron microscopy, Raman mapping and molecular dynamics simulations revealed that higher NaCl concentrations can promote the coalescence of independent local strain domains, further increasing the 1T/2H phase ratio and defect density. Furthermore, excessive NaCl was also proven by density functional theory calculations to convert thermodynamic growth to kinetic growth, accounting for the unique cloud-shaped MoS2 crystals acquired. Compared with post-growth strain processing methods, this one-step approach for phase and defect engineering not only represents a deeper understanding of the role that NaCl plays in the CVD process, but also provides a convenient means to controllably synthesize conductive/defect-rich materials for further electrocatalysis and optoelectronic applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Alkali metal halides have recently received great attention as additives in the chemical vapor deposition (CVD) process to promote the growth of transition metal dichalcogenides (TMDs). However, the multi-faceted role of these halide salts in modulating the properties and quality of TMD monolayers remains mechanistically unclear. In this study, by introducing excessive gaseous sodium chloride (NaCl) into the CVD system, we demonstrate that preferential NaCl deposition along the monolayer edges causes large in situ strain that can invoke localized domains of high defect density and 2H to 1T phase transition. High-resolution scanning transmission electron microscopy, Raman mapping and molecular dynamics simulations revealed that higher NaCl concentrations can promote the coalescence of independent local strain domains, further increasing the 1T/2H phase ratio and defect density. Furthermore, excessive NaCl was also proven by density functional theory calculations to convert thermodynamic growth to kinetic growth, accounting for the unique cloud-shaped MoS2 crystals acquired. Compared with post-growth strain processing methods, this one-step approach for phase and defect engineering not only represents a deeper understanding of the role that NaCl plays in the CVD process, but also provides a convenient means to controllably synthesize conductive/defect-rich materials for further electrocatalysis and optoelectronic applications. |
2022 |
Linghu, Jiajun; Song, Tingting; Yang, Tong; Zhou, Jun; Lim, Kimyong; Sow, Chornghaur; Yang, Ming; Feng, Yuanping; Wang, Xuezhi Computational prediction of stable semiconducting Zn-C binary compounds Journal Article MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, 155 , 2022, ISSN: 1369-8001. @article{ISI:000908382200001, title = {Computational prediction of stable semiconducting Zn-C binary compounds}, author = {Jiajun Linghu and Tingting Song and Tong Yang and Jun Zhou and Kimyong Lim and Chornghaur Sow and Ming Yang and Yuanping Feng and Xuezhi Wang}, doi = {10.1016/j.mssp.2022.107237}, times_cited = {0}, issn = {1369-8001}, year = {2022}, date = {2022-11-25}, journal = {MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING}, volume = {155}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {Elemental carbon has been successfully used to tune the light emission properties of zinc oxide (ZnO) through artificially doping but the underlying mechanism remains controversial. At present, carbon-related defect complexes are the main explanation. Nevertheless, the possibility of forming semiconducting Zn-C compounds has not been discussed. In this study, we reveal the existence of various stable semiconducting Zn-C compounds. Based on particle swarm optimization and first-principles calculations, we perform a structural search of Zn-C binary compounds and report four stable semiconducting structures, in which the covalent Zn-C bonding characteristics are stronger compared with that in the metal rocksalt zinc carbide (ZnC). Crucially, three of the four Zn-C compounds have direct or quasi-direct band gaps in the range of 1.09-2.94 eV which are energies highly desirable for optoelectronic applications. Electronic transitions across the band gaps of these Zn-C structures could contribute to blue and near-infrared light emissions of C-doped ZnO. Our results have not only unraveled a new perspective to explain and tailor the light emission properties of ZnO but also provide a deeper understanding of possible Zn-C compounds.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Elemental carbon has been successfully used to tune the light emission properties of zinc oxide (ZnO) through artificially doping but the underlying mechanism remains controversial. At present, carbon-related defect complexes are the main explanation. Nevertheless, the possibility of forming semiconducting Zn-C compounds has not been discussed. In this study, we reveal the existence of various stable semiconducting Zn-C compounds. Based on particle swarm optimization and first-principles calculations, we perform a structural search of Zn-C binary compounds and report four stable semiconducting structures, in which the covalent Zn-C bonding characteristics are stronger compared with that in the metal rocksalt zinc carbide (ZnC). Crucially, three of the four Zn-C compounds have direct or quasi-direct band gaps in the range of 1.09-2.94 eV which are energies highly desirable for optoelectronic applications. Electronic transitions across the band gaps of these Zn-C structures could contribute to blue and near-infrared light emissions of C-doped ZnO. Our results have not only unraveled a new perspective to explain and tailor the light emission properties of ZnO but also provide a deeper understanding of possible Zn-C compounds. |
Wang, Xinyun; Zhao, Yuzhou; Kong, Xiao; Zhang, Qi; Ng, Hong Kuan; Lim, Sharon Xiaodai; Zheng, Yue; Wu, Xiao; Watanabe, Kenji; Xu, Qing-Hua; Taniguchi, Takashi; Eda, Goki; Goh, Kuan Eng Johnson; Jin, Song; Loh, Kian Ping; Ding, Feng; Sun, Wanxin; Sow, Chorng Haur Dynamic Tuning of Moire Superlattice Morphology by Laser Modification Journal Article ACS NANO , 16 (5), pp. 8172-8180, 2022, ISSN: 1936-0851. @article{ISI:000812148900091, title = {Dynamic Tuning of Moire Superlattice Morphology by Laser Modification }, author = {Xinyun Wang and Yuzhou Zhao and Xiao Kong and Qi Zhang and Hong Kuan Ng and Sharon Xiaodai Lim and Yue Zheng and Xiao Wu and Kenji Watanabe and Qing-Hua Xu and Takashi Taniguchi and Goki Eda and Kuan Eng Johnson Goh and Song Jin and Kian Ping Loh and Feng Ding and Wanxin Sun and Chorng Haur Sow}, doi = {10.1021/acsnano.2c01625}, times_cited = {0}, issn = {1936-0851}, year = {2022}, date = {2022-05-24}, journal = {ACS NANO }, volume = {16}, number = {5}, pages = {8172-8180}, publisher = {AMER CHEMICAL SOC }, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA }, abstract = {In artificial van der Waals (vdW) layered devices, twisting the stacking angle has emerged as an effective strategy to regulate the electronic phases and optical properties of these systems. Along with the twist registry, the lattice reconstruction arising from vdW interlayer interaction has also inspired significant research interests. The control of twist angles is significantly important because the moire periodicity determines the electron propagation length on the lattice and the interlayer electron-electron interactions. However, the moire periodicity is hard to be modified after the device has been fabricated. In this work, we have demonstrated that the moire periodicity can be precisely modulated with a localized laser annealing technique. This is achieved with regulating the interlayer lattice mismatch by the mismatched lattice constant, which originates from the variable density of sulfur vacancy generated during laser modification. The existence of sulfur vacancy is further verified by excitonic emission energy and lifetime in photoluminescence measurements. Furthermore, we also discover that the mismatched lattice constant has the equivalent contribution as the twist angle for determining the lattice mismatch. Theoretical modeling elaborates the moire-wavelength-dependent energy variations at the interface and mimics the evolution of moire morphology. }, keywords = {}, pubstate = {published}, tppubtype = {article} } In artificial van der Waals (vdW) layered devices, twisting the stacking angle has emerged as an effective strategy to regulate the electronic phases and optical properties of these systems. Along with the twist registry, the lattice reconstruction arising from vdW interlayer interaction has also inspired significant research interests. The control of twist angles is significantly important because the moire periodicity determines the electron propagation length on the lattice and the interlayer electron-electron interactions. However, the moire periodicity is hard to be modified after the device has been fabricated. In this work, we have demonstrated that the moire periodicity can be precisely modulated with a localized laser annealing technique. This is achieved with regulating the interlayer lattice mismatch by the mismatched lattice constant, which originates from the variable density of sulfur vacancy generated during laser modification. The existence of sulfur vacancy is further verified by excitonic emission energy and lifetime in photoluminescence measurements. Furthermore, we also discover that the mismatched lattice constant has the equivalent contribution as the twist angle for determining the lattice mismatch. Theoretical modeling elaborates the moire-wavelength-dependent energy variations at the interface and mimics the evolution of moire morphology. |
Chen, Bochao; Zhang, Hanwen; Liang, Ming; Wang, Yuxuan; Wu, Zhiyi; Zhu, Shan; Shi, Chunsheng; Zhao, Naiqin; Liu, Enzuo; Sow, Chorng Haur; He, Chunnian NaCl-pinned antimony nanoparticles combined with ion-shuttle-induced graphitized 3D carbon to boost sodium storage Journal Article CELL REPORTS PHYSICAL SCIENCE, 3 (5), 2022. @article{ISI:000840855100006, title = {NaCl-pinned antimony nanoparticles combined with ion-shuttle-induced graphitized 3D carbon to boost sodium storage}, author = {Bochao Chen and Hanwen Zhang and Ming Liang and Yuxuan Wang and Zhiyi Wu and Shan Zhu and Chunsheng Shi and Naiqin Zhao and Enzuo Liu and Chorng Haur Sow and Chunnian He}, doi = {10.1016/j.xcrp.2022.100891}, times_cited = {0}, year = {2022}, date = {2022-05-18}, journal = {CELL REPORTS PHYSICAL SCIENCE}, volume = {3}, number = {5}, publisher = {CELL PRESS}, address = {50 HAMPSHIRE ST, FLOOR 5, CAMBRIDGE, MA 02139 USA}, abstract = {Abundant sodium resources provide compelling competitive advantage for sodium-ion battery (SIBs) applications. Correspondingly, it is urgently required to develop high-performance and low-cost anode materials for SIBs. Here, we report a composite of antimony nanoparticles anchored on N/S co-doped 3D carbon for superior SIB anodes. During the synthesis, NaCl exerts a "pinning effect" to restrict the growth of antimony in the carbon matrix and results in nano-sized antimony particles. Given the enhanced-charge/ion-transfer kinetics ensured by nano-Sb and the structural advantages derived from the N/S co-doped 3D porous carbon, which not only remain robust upon cycling but also undergo graphitization by the ion shuttle effect to stimulate a stronger electrochemical response during the activation process, this composite maintains a 98.9% capacity ratio over 20,000 cycles at 10 A g(-1) Furthermore, molecular dynamics simulations reveal that the degree of graphitization has a linear relationship with the ionic radius.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abundant sodium resources provide compelling competitive advantage for sodium-ion battery (SIBs) applications. Correspondingly, it is urgently required to develop high-performance and low-cost anode materials for SIBs. Here, we report a composite of antimony nanoparticles anchored on N/S co-doped 3D carbon for superior SIB anodes. During the synthesis, NaCl exerts a "pinning effect" to restrict the growth of antimony in the carbon matrix and results in nano-sized antimony particles. Given the enhanced-charge/ion-transfer kinetics ensured by nano-Sb and the structural advantages derived from the N/S co-doped 3D porous carbon, which not only remain robust upon cycling but also undergo graphitization by the ion shuttle effect to stimulate a stronger electrochemical response during the activation process, this composite maintains a 98.9% capacity ratio over 20,000 cycles at 10 A g(-1) Furthermore, molecular dynamics simulations reveal that the degree of graphitization has a linear relationship with the ionic radius. |
Wang, Xinyun; Zhao, Yuzhou; Kong, Xiao; Zhang, Qi; Ng, Hong Kuan; Lim, Sharon Xiaodai; Zheng, Yue; Wu, Xiao; Watanabe, Kenji; Xu, Qing-Hua; Taniguchi, Takashi; Eda, Goki; Goh, Kuan Eng Johnson; Jin, Song; Loh, Kian Ping; Ding, Feng; Sun, Wanxin; Sow, Chorng Haur Dynamic Tuning of Moire Superlattice Morphology by Laser Modification Journal Article ACS NANO, 16 (5), pp. 8172-8180, 2022, ISSN: 1936-0851. @article{ISI:000820334500001, title = {Dynamic Tuning of Moire Superlattice Morphology by Laser Modification}, author = {Xinyun Wang and Yuzhou Zhao and Xiao Kong and Qi Zhang and Hong Kuan Ng and Sharon Xiaodai Lim and Yue Zheng and Xiao Wu and Kenji Watanabe and Qing-Hua Xu and Takashi Taniguchi and Goki Eda and Kuan Eng Johnson Goh and Song Jin and Kian Ping Loh and Feng Ding and Wanxin Sun and Chorng Haur Sow}, doi = {10.1021/acsnano.2c01625}, times_cited = {0}, issn = {1936-0851}, year = {2022}, date = {2022-05-16}, journal = {ACS NANO}, volume = {16}, number = {5}, pages = {8172-8180}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {In artificial van der Waals (vdW) layered devices, twisting the stacking angle has emerged as an effective strategy to regulate the electronic phases and optical properties of these systems. Along with the twist registry, the lattice reconstruction arising from vdW interlayer interaction has also inspired significant research interests. The control of twist angles is significantly important because the moire periodicity determines the electron propagation length on the lattice and the interlayer electron-electron interactions. However, the moire periodicity is hard to be modified after the device has been fabricated. In this work, we have demonstrated that the moire periodicity can be precisely modulated with a localized laser annealing technique. This is achieved with regulating the interlayer lattice mismatch by the mismatched lattice constant, which originates from the variable density of sulfur vacancy generated during laser modification. The existence of sulfur vacancy is further verified by excitonic emission energy and lifetime in photoluminescence measurements. Furthermore, we also discover that the mismatched lattice constant has the equivalent contribution as the twist angle for determining the lattice mismatch. Theoretical modeling elaborates the moire-wavelength-dependent energy variations at the interface and mimics the evolution of moire morphology.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In artificial van der Waals (vdW) layered devices, twisting the stacking angle has emerged as an effective strategy to regulate the electronic phases and optical properties of these systems. Along with the twist registry, the lattice reconstruction arising from vdW interlayer interaction has also inspired significant research interests. The control of twist angles is significantly important because the moire periodicity determines the electron propagation length on the lattice and the interlayer electron-electron interactions. However, the moire periodicity is hard to be modified after the device has been fabricated. In this work, we have demonstrated that the moire periodicity can be precisely modulated with a localized laser annealing technique. This is achieved with regulating the interlayer lattice mismatch by the mismatched lattice constant, which originates from the variable density of sulfur vacancy generated during laser modification. The existence of sulfur vacancy is further verified by excitonic emission energy and lifetime in photoluminescence measurements. Furthermore, we also discover that the mismatched lattice constant has the equivalent contribution as the twist angle for determining the lattice mismatch. Theoretical modeling elaborates the moire-wavelength-dependent energy variations at the interface and mimics the evolution of moire morphology. |
Gan, Lu; Lim, Sharon Xiaodai; Sow, Chorng-Haur Nanopath-Beacons for Directed Silver Dendrites' Migration across Graphene Oxide Terrain Journal Article ACS OMEGA, 7 (12), pp. 10330-10339, 2022, ISSN: 2470-1343. @article{ISI:000783983200036, title = {Nanopath-Beacons for Directed Silver Dendrites' Migration across Graphene Oxide Terrain}, author = {Lu Gan and Sharon Xiaodai Lim and Chorng-Haur Sow}, doi = {10.1021/acsomega.1c06963}, times_cited = {0}, issn = {2470-1343}, year = {2022}, date = {2022-03-29}, journal = {ACS OMEGA}, volume = {7}, number = {12}, pages = {10330-10339}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {With their special hierarchical fractal and highly symmetric formation, silver dendrites have a large surface area and plentiful active sites at edges, which have allowed them to exhibit unique properties ranging from superhydrophobic surfaces to biosensors. Yet, many suggested synthesis processes either require a long reaction time or risk contamination from sacrificial elements. Limited research in directing while enhancing the growth of these silver dendrites also hinders the application of these unique microstructures as site-selective hydrophobicity of surfaces and location-dependent SERS (surface-enhanced Raman spectroscopy). A possible solution to this is to utilize WO3 nanocubes as beacons to accelerate and conduct the growth of these silver dendrites through the electrochemical migration process. These nanocubes effortlessly altered the applied electric field distributed between the electrodes, depending on their orientations and positions. As the silver dendrites branched from the nanocubes, the dendrites themselves further concentrated the electric field to encourage the growth of more loose fractal silver dendrites. The combinatory effect successfully directs the growth of silver dendrites along the concentrated electric field paths. Both changes to the electric field and directed growth of silver dendrites are underscored using Multiphysics COMSOL simulations and time-lapse microscopy. This work provided insight into the possibility of designing microstructures to direct and accelerate the growth of silver dendrites.}, keywords = {}, pubstate = {published}, tppubtype = {article} } With their special hierarchical fractal and highly symmetric formation, silver dendrites have a large surface area and plentiful active sites at edges, which have allowed them to exhibit unique properties ranging from superhydrophobic surfaces to biosensors. Yet, many suggested synthesis processes either require a long reaction time or risk contamination from sacrificial elements. Limited research in directing while enhancing the growth of these silver dendrites also hinders the application of these unique microstructures as site-selective hydrophobicity of surfaces and location-dependent SERS (surface-enhanced Raman spectroscopy). A possible solution to this is to utilize WO3 nanocubes as beacons to accelerate and conduct the growth of these silver dendrites through the electrochemical migration process. These nanocubes effortlessly altered the applied electric field distributed between the electrodes, depending on their orientations and positions. As the silver dendrites branched from the nanocubes, the dendrites themselves further concentrated the electric field to encourage the growth of more loose fractal silver dendrites. The combinatory effect successfully directs the growth of silver dendrites along the concentrated electric field paths. Both changes to the electric field and directed growth of silver dendrites are underscored using Multiphysics COMSOL simulations and time-lapse microscopy. This work provided insight into the possibility of designing microstructures to direct and accelerate the growth of silver dendrites. |
Sahdan, Muhammad Fauzi; Arramel, ; Xiaodai, Sharon Lim; Wang, Hong; Birowosuto, Muhammad Danang; Haur, Sow Chorng; Ang, Kah-Wee; Wee, Andrew Thye Shen Metal-insulator transition switching in VOx-VSe2 heterojunctions Journal Article PHYSICAL REVIEW MATERIALS, 6 (1), 2022, ISSN: 2475-9953. @article{ISI:000747807700002, title = {Metal-insulator transition switching in VO_{\textit{x}}-VSe_{2} heterojunctions}, author = {Muhammad Fauzi Sahdan and Arramel and Sharon Lim Xiaodai and Hong Wang and Muhammad Danang Birowosuto and Sow Chorng Haur and Kah-Wee Ang and Andrew Thye Shen Wee}, doi = {10.1103/PhysRevMaterials.6.014003}, times_cited = {0}, issn = {2475-9953}, year = {2022}, date = {2022-01-19}, journal = {PHYSICAL REVIEW MATERIALS}, volume = {6}, number = {1}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {First-order metal-insulator transition (MIT) observed in strongly correlated systems such as vanadium dioxide (VO2) holds potential in electronics, energy, to optical applications. Starting from a vanadium diselenide (VSe2) bulk crystal, we demonstrated a direct surface conversion from VSe2 to VO2 via laser exposure in ambient condition. The process generates defects, and the heat from the laser promotes oxidation forming VOx. Raman spectra at room temperature suggest the resulting oxide formed is monoclinic (M1) VO2. Above the transition temperature (T-C), all the phonon modes are damped indicating formation of the rutile phase (metallic). Photoluminescence (PL) intensity enhancement and peak shifts observed at T-C suggest correlation to the band structure transformation. In addition, we observed electrically induced MIT in our lateral VSe2-VOx heterojunction device.}, keywords = {}, pubstate = {published}, tppubtype = {article} } First-order metal-insulator transition (MIT) observed in strongly correlated systems such as vanadium dioxide (VO2) holds potential in electronics, energy, to optical applications. Starting from a vanadium diselenide (VSe2) bulk crystal, we demonstrated a direct surface conversion from VSe2 to VO2 via laser exposure in ambient condition. The process generates defects, and the heat from the laser promotes oxidation forming VOx. Raman spectra at room temperature suggest the resulting oxide formed is monoclinic (M1) VO2. Above the transition temperature (T-C), all the phonon modes are damped indicating formation of the rutile phase (metallic). Photoluminescence (PL) intensity enhancement and peak shifts observed at T-C suggest correlation to the band structure transformation. In addition, we observed electrically induced MIT in our lateral VSe2-VOx heterojunction device. |
2021 |
Costa, Mariana C F; Marangoni, Valeria S; Trushin, Maxim; Carvalho, Alexandra; Lim, Sharon X; Nguyen, Hang T L; Ng, Pei Rou; Zhao, Xiaoxu; Donato, Ricardo K; Pennycook, Stephen J; Sow, Chorng H; Novoselov, Konstantin S; Neto, Antonio Castro H 2D Electrolytes: Theory, Modeling, Synthesis, and Characterization Journal Article ADVANCED MATERIALS, 33 (25), 2021, ISSN: 0935-9648. @article{ISI:000649261200001, title = {2D Electrolytes: Theory, Modeling, Synthesis, and Characterization}, author = {Mariana C F Costa and Valeria S Marangoni and Maxim Trushin and Alexandra Carvalho and Sharon X Lim and Hang T L Nguyen and Pei Rou Ng and Xiaoxu Zhao and Ricardo K Donato and Stephen J Pennycook and Chorng H Sow and Konstantin S Novoselov and Antonio Castro H Neto}, doi = {10.1002/adma.202100442}, times_cited = {0}, issn = {0935-9648}, year = {2021}, date = {2021-05-12}, journal = {ADVANCED MATERIALS}, volume = {33}, number = {25}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {A class of compounds sharing the properties of 2D materials and electrolytes, namely 2D electrolytes is described theoretically and demonstrated experimentally. 2D electrolytes dissociate in different solvents, such as water, and become electrically charged. The chemical and physical properties of these compounds can be controlled by external factors, such as pH, temperature, electric permittivity of the medium, and ionic concentration. 2D electrolytes, in analogy with polyelectrolytes, present reversible morphological transitions from 2D to 1D, as a function of pH, due to the interplay of the elastic and Coulomb energies. Since these materials show stimuli-responsive behavior to the environmental conditions, 2D electrolytes can be considered as a novel class of smart materials that expand the functionalities of 2D materials and are promising for applications that require stimuli-responsive demeanor, such as drug delivery, artificial muscles, and energy storage.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A class of compounds sharing the properties of 2D materials and electrolytes, namely 2D electrolytes is described theoretically and demonstrated experimentally. 2D electrolytes dissociate in different solvents, such as water, and become electrically charged. The chemical and physical properties of these compounds can be controlled by external factors, such as pH, temperature, electric permittivity of the medium, and ionic concentration. 2D electrolytes, in analogy with polyelectrolytes, present reversible morphological transitions from 2D to 1D, as a function of pH, due to the interplay of the elastic and Coulomb energies. Since these materials show stimuli-responsive behavior to the environmental conditions, 2D electrolytes can be considered as a novel class of smart materials that expand the functionalities of 2D materials and are promising for applications that require stimuli-responsive demeanor, such as drug delivery, artificial muscles, and energy storage. |
Ma, Yaping; Shao, Xiji; Li, Jing; Dong, Bowei; Hu, Zhenliang; Zhou, Qiulan; Xu, Haomin; Zhao, Xiaoxu; Fang, Hanyan; Li, Xinzhe; Li, Zejun; Wu, Jing; Zhao, Meng; Pennycook, Stephen John; Sow, Chorng Haur; Lee, Chengkuo; Zhong, Yu Lin; Lu, Junpeng; Ding, Mengning; Wang, Kedong; Li, Ying; Lu, Jiong Electrochemically Exfoliated Platinum Dichalcogenide Atomic Layers for High-Performance Air-Stable Infrared Photodetectors Journal Article ACS APPLIED MATERIALS & INTERFACES, 13 (7), pp. 8518-8527, 2021, ISSN: 1944-8244. @article{ISI:000623228500064, title = {Electrochemically Exfoliated Platinum Dichalcogenide Atomic Layers for High-Performance Air-Stable Infrared Photodetectors}, author = {Yaping Ma and Xiji Shao and Jing Li and Bowei Dong and Zhenliang Hu and Qiulan Zhou and Haomin Xu and Xiaoxu Zhao and Hanyan Fang and Xinzhe Li and Zejun Li and Jing Wu and Meng Zhao and Stephen John Pennycook and Chorng Haur Sow and Chengkuo Lee and Yu Lin Zhong and Junpeng Lu and Mengning Ding and Kedong Wang and Ying Li and Jiong Lu}, doi = {10.1021/acsami.0c20535}, times_cited = {0}, issn = {1944-8244}, year = {2021}, date = {2021-02-11}, journal = {ACS APPLIED MATERIALS & INTERFACES}, volume = {13}, number = {7}, pages = {8518-8527}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Platinum dichalcogenide (PtX2), an emergent group-10 transition metal dichalcogenide (TMD) has shown great potential in infrared photonic and optoelectronic applications due to its layer-dependent electronic structure with potentially suitable bandgap. However, a scalable synthesis of PtSe2 and PtTe2 atomic layers with controlled thickness still represents a major challenge in this field because of the strong interlayer interactions. Herein, we develop a facile cathodic exfoliation approach for the synthesis of solution-processable high-quality PtSe2 and PtTe2 atomic layers for high-performance infrared (IR) photodetection. As-exfoliated PtSe2 and PtTe2 bilayer exhibit an excellent photoresponsivity of 72 and 1620 mA W-1 at zero gate voltage under a 1540 nm laser illumination, respectively, approximately several orders of magnitude higher than that of the majority of IR photodetectors based on graphene, TMDs, and black phosphorus. In addition, our PtSe2 and PtTe2 bilayer device also shows a decent specific detectivity of beyond 10(9) Jones with remarkable air-stability (>several months), outperforming the mechanically exfoliated counterparts under the laser illumination with a similar wavelength. Moreover, a high yield of PtSe2 and PtTe2 atomic layers dispersed in solution also allows for a facile fabrication of air-stable wafer-scale IR photodetector. This work demonstrates a new route for the synthesis of solution-processable layered materials with the narrow bandgap for the infrared optoelectronic applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Platinum dichalcogenide (PtX2), an emergent group-10 transition metal dichalcogenide (TMD) has shown great potential in infrared photonic and optoelectronic applications due to its layer-dependent electronic structure with potentially suitable bandgap. However, a scalable synthesis of PtSe2 and PtTe2 atomic layers with controlled thickness still represents a major challenge in this field because of the strong interlayer interactions. Herein, we develop a facile cathodic exfoliation approach for the synthesis of solution-processable high-quality PtSe2 and PtTe2 atomic layers for high-performance infrared (IR) photodetection. As-exfoliated PtSe2 and PtTe2 bilayer exhibit an excellent photoresponsivity of 72 and 1620 mA W-1 at zero gate voltage under a 1540 nm laser illumination, respectively, approximately several orders of magnitude higher than that of the majority of IR photodetectors based on graphene, TMDs, and black phosphorus. In addition, our PtSe2 and PtTe2 bilayer device also shows a decent specific detectivity of beyond 10(9) Jones with remarkable air-stability (>several months), outperforming the mechanically exfoliated counterparts under the laser illumination with a similar wavelength. Moreover, a high yield of PtSe2 and PtTe2 atomic layers dispersed in solution also allows for a facile fabrication of air-stable wafer-scale IR photodetector. This work demonstrates a new route for the synthesis of solution-processable layered materials with the narrow bandgap for the infrared optoelectronic applications. |
2020 |
Lin, Fanrong; Qiao, Jiabin; Huang, Junye; Liu, Jiawei; Fu, Deyi; Mayorov, Alexander S; Chen, Hao; Mukherjee, Paromita; Qu, Tingyu; Sow, Chorng-Haur; Watanabe, Kenji; Taniguchi, Takashi; Ozyilmaz, Barbaros Heteromoire Engineering on Magnetic Bloch Transport in Twisted Graphene Superlattices Journal Article NANO LETTERS, 20 (10), pp. 7572-7579, 2020, ISSN: 1530-6984. @article{ISI:000613073900006, title = {Heteromoire Engineering on Magnetic Bloch Transport in Twisted Graphene Superlattices}, author = {Fanrong Lin and Jiabin Qiao and Junye Huang and Jiawei Liu and Deyi Fu and Alexander S Mayorov and Hao Chen and Paromita Mukherjee and Tingyu Qu and Chorng-Haur Sow and Kenji Watanabe and Takashi Taniguchi and Barbaros Ozyilmaz}, doi = {10.1021/acs.nanolett.0c03062}, times_cited = {0}, issn = {1530-6984}, year = {2020}, date = {2020-10-14}, journal = {NANO LETTERS}, volume = {20}, number = {10}, pages = {7572-7579}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Localized electrons subject to applied magnetic fields can restart to propagate freely through the lattice in delocalized magnetic Bloch states (MBSs) when the lattice periodicity is commensurate with the magnetic length. Twisted graphene superlattices with moire wavelength tunability enable experimental access to the unique delocalization in a controllable fashion. Here, we report the observation and characterization of high-temperature Brown-Zak (BZ) oscillations which come in two types, 1/B and B periodicity, originating from the generation of integer and fractional MBSs, in the twisted bilayer and trilayer graphene superlattices, respectively. Coexisting periodic-in-1/B oscillations assigned to different moire wavelengths are dramatically observed in small-angle twisted bilayer graphene, which may arise from angledisorder-induced in-plane heteromoire superlattices. Moreover, the vertical stacking of heteromoire supercells in double-twisted trilayer graphene results in a mega-sized superlattice. The exotic superlattice contributes to the periodic-in-B oscillation and dominates the magnetic Bloch transport.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Localized electrons subject to applied magnetic fields can restart to propagate freely through the lattice in delocalized magnetic Bloch states (MBSs) when the lattice periodicity is commensurate with the magnetic length. Twisted graphene superlattices with moire wavelength tunability enable experimental access to the unique delocalization in a controllable fashion. Here, we report the observation and characterization of high-temperature Brown-Zak (BZ) oscillations which come in two types, 1/B and B periodicity, originating from the generation of integer and fractional MBSs, in the twisted bilayer and trilayer graphene superlattices, respectively. Coexisting periodic-in-1/B oscillations assigned to different moire wavelengths are dramatically observed in small-angle twisted bilayer graphene, which may arise from angledisorder-induced in-plane heteromoire superlattices. Moreover, the vertical stacking of heteromoire supercells in double-twisted trilayer graphene results in a mega-sized superlattice. The exotic superlattice contributes to the periodic-in-B oscillation and dominates the magnetic Bloch transport. |
Lim, Sharon Xiaodai; Zhang, Zheng; Koon, Gavin Kok Wai; Sow, Chorng-Haur Unlocking the potential of carbon incorporated silver-silver molybdate nanowire with light Journal Article APPLIED MATERIALS TODAY, 20 , 2020, ISSN: 2352-9407. @article{ISI:000598818600003, title = {Unlocking the potential of carbon incorporated silver-silver molybdate nanowire with light}, author = {Sharon Xiaodai Lim and Zheng Zhang and Gavin Kok Wai Koon and Chorng-Haur Sow}, doi = {10.1016/j.apmt.2020.100670}, times_cited = {0}, issn = {2352-9407}, year = {2020}, date = {2020-09-01}, journal = {APPLIED MATERIALS TODAY}, volume = {20}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {We present a novel form of Ag2MoO4-based hybrid nanowire (NW) with a few remarkable attributes. Firstly, the NW is embedded and decorated with Ag NPs. Secondly, carbon atoms are intentionally incorporated within the matrix of the NW. Thirdly the hybrid nanowires are created via a facile process. Namely, focused laser micropatterning of Ag NPs on GO film as seeding sites and subsequent formation of the hybrid NWs by placing the patterned GO films on heated Mo foil on a hotplate. This unique process resulted in the production of hybrid Ag/Ag2MoO4 NWs that emit unique red fluorescence emission. And finally remarkable photodoping effect is observed from a single strand of optically tuned carbon-doped silver nanoparticles embedded silver molybdate nanowire. We demonstrate applications of these hybrid NWs as micro-display and time limiting, logic components for secure transmission of messages. (C) 2020 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present a novel form of Ag2MoO4-based hybrid nanowire (NW) with a few remarkable attributes. Firstly, the NW is embedded and decorated with Ag NPs. Secondly, carbon atoms are intentionally incorporated within the matrix of the NW. Thirdly the hybrid nanowires are created via a facile process. Namely, focused laser micropatterning of Ag NPs on GO film as seeding sites and subsequent formation of the hybrid NWs by placing the patterned GO films on heated Mo foil on a hotplate. This unique process resulted in the production of hybrid Ag/Ag2MoO4 NWs that emit unique red fluorescence emission. And finally remarkable photodoping effect is observed from a single strand of optically tuned carbon-doped silver nanoparticles embedded silver molybdate nanowire. We demonstrate applications of these hybrid NWs as micro-display and time limiting, logic components for secure transmission of messages. (C) 2020 Elsevier Ltd. All rights reserved. |
Yan, Zhiyuan; Poh, Eng Tuan; Zhang, Zheng; Chua, Sing Teng; Wang, Xinyun; Wu, Xiao; Chen, Zhihui; Yang, Jing; Xu, Qing-Hua; Goh, Kuan Eng Johnson; Zhao, Rong; Sow, Chorng-Haur Band Nesting Bypass in WS2 Monolayers via Forster Resonance Energy Transfer Journal Article ACS NANO, 14 (5), pp. 5946-5955, 2020, ISSN: 1936-0851. @article{ISI:000537682300078, title = {Band Nesting Bypass in WS_{2} Monolayers \textit{via} Forster Resonance Energy Transfer}, author = {Zhiyuan Yan and Eng Tuan Poh and Zheng Zhang and Sing Teng Chua and Xinyun Wang and Xiao Wu and Zhihui Chen and Jing Yang and Qing-Hua Xu and Kuan Eng Johnson Goh and Rong Zhao and Chorng-Haur Sow}, doi = {10.1021/acsnano.0c01407}, times_cited = {1}, issn = {1936-0851}, year = {2020}, date = {2020-05-26}, journal = {ACS NANO}, volume = {14}, number = {5}, pages = {5946-5955}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Two-dimensional (2D) transition-metal dichalcogenides (TMDs) have attracted intensive interest due to the direct-band-gap transition in the monolayer form, positioning them as potential next-generation materials for optoelectronic or photonic devices. However, the band-nested suppression of the recombination efficiency at higher excitation energies limits the ability to locally control and manipulate the photoluminescence of WS2 for multifunctional applications. In this work, we exploit an energy transfer method to modulate the fluorescence properties of TMDs under a larger excitation range spanning from UV to visible light. Self-assembled lanthanide (Ln)/TMD hybrids have been designed based on a low-cost and highly efficient solution-processed approach. The emission energy from Ln(3+) sources can be effectively transferred to the TMD monolayers under low power exposure (0.13 mW) at room temperature, activating the characteristic monolayer fluorescence in place of Ln(3+) emission signatures. The Ln/TMDs photonics can potentially tune the excitation of TMDs to provide variable yet controllable emissions. This provides a solution to the suppression of direct exciton recombination in monolayer TMDs at the band nesting resonant energy region. Our work on such Ln/TMD systems would overcome the limited excitation energy range in TMDs and extend their functionalities for optoelectronic or photonic applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two-dimensional (2D) transition-metal dichalcogenides (TMDs) have attracted intensive interest due to the direct-band-gap transition in the monolayer form, positioning them as potential next-generation materials for optoelectronic or photonic devices. However, the band-nested suppression of the recombination efficiency at higher excitation energies limits the ability to locally control and manipulate the photoluminescence of WS2 for multifunctional applications. In this work, we exploit an energy transfer method to modulate the fluorescence properties of TMDs under a larger excitation range spanning from UV to visible light. Self-assembled lanthanide (Ln)/TMD hybrids have been designed based on a low-cost and highly efficient solution-processed approach. The emission energy from Ln(3+) sources can be effectively transferred to the TMD monolayers under low power exposure (0.13 mW) at room temperature, activating the characteristic monolayer fluorescence in place of Ln(3+) emission signatures. The Ln/TMDs photonics can potentially tune the excitation of TMDs to provide variable yet controllable emissions. This provides a solution to the suppression of direct exciton recombination in monolayer TMDs at the band nesting resonant energy region. Our work on such Ln/TMD systems would overcome the limited excitation energy range in TMDs and extend their functionalities for optoelectronic or photonic applications. |
Sow, Bryan Miaoxuan; Lim, Kim Yong; Wu, Jianfeng; Sow, Chorng-Haur Electrically Tailored Metachrosis in ZnO-C Nanowires Journal Article ACS NANO, 14 (5), pp. 5845-5854, 2020, ISSN: 1936-0851. @article{ISI:000537682300068, title = {Electrically Tailored Metachrosis in ZnO-C Nanowires}, author = {Bryan Miaoxuan Sow and Kim Yong Lim and Jianfeng Wu and Chorng-Haur Sow}, doi = {10.1021/acsnano.0c00983}, times_cited = {0}, issn = {1936-0851}, year = {2020}, date = {2020-05-26}, journal = {ACS NANO}, volume = {14}, number = {5}, pages = {5845-5854}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Carbon incorporated zinc oxide (ZnO:C) nanowires (NWs) are found to be remarkable morphing NWs. We show that the physical properties of ZnO:C NWs are engineered via the passage of electric current to produce fluorescence differences and negative differential resistance as well as electroluminescence. When a ZnO:C NW is subjected to an applied voltage bias and under ultraviolet (UV) excitation, electron-hole separation due to the voltage biasing suppresses their fluorescence at low voltages. At medium voltages, the NW exhibits metastable chemical changes that translates to tunable and reversible optical alterations akin to metachrosis found in chameleons. Concurrently, the NW displays electrical alterations with negative differential resistance behaviors. At higher voltages, these NWs are permanently modified with distinct heterogeneous chemical stoichiometry, fluorescence, and electronic properties. Such heterogeneity within the NW allows for emergence of junctions capable of electroluminescence.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Carbon incorporated zinc oxide (ZnO:C) nanowires (NWs) are found to be remarkable morphing NWs. We show that the physical properties of ZnO:C NWs are engineered via the passage of electric current to produce fluorescence differences and negative differential resistance as well as electroluminescence. When a ZnO:C NW is subjected to an applied voltage bias and under ultraviolet (UV) excitation, electron-hole separation due to the voltage biasing suppresses their fluorescence at low voltages. At medium voltages, the NW exhibits metastable chemical changes that translates to tunable and reversible optical alterations akin to metachrosis found in chameleons. Concurrently, the NW displays electrical alterations with negative differential resistance behaviors. At higher voltages, these NWs are permanently modified with distinct heterogeneous chemical stoichiometry, fluorescence, and electronic properties. Such heterogeneity within the NW allows for emergence of junctions capable of electroluminescence. |
2019 |
Poh, Eng Tuan; Liu, Xiaogang; Sow, Chorng Haur Laser-Guided Microcanvas Printing of Multicolor Upconversion Nanoparticles on Molybdenum Disulfide Monolayer Journal Article ADVANCED MATERIALS INTERFACES, 6 (24), 2019, ISSN: 2196-7350. @article{ISI:000497859700001, title = {Laser-Guided Microcanvas Printing of Multicolor Upconversion Nanoparticles on Molybdenum Disulfide Monolayer}, author = {Eng Tuan Poh and Xiaogang Liu and Chorng Haur Sow}, doi = {10.1002/admi.201901673}, times_cited = {3}, issn = {2196-7350}, year = {2019}, date = {2019-11-22}, journal = {ADVANCED MATERIALS INTERFACES}, volume = {6}, number = {24}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {Scanning focused laser beams incident on nanomaterials have provided a nondestructive and facile technique to fabricate micropatterns of a wide variety of hybrid materials. Conventionally, the technique is limited to localized chemical modification or in situ reduction of specific metal ions en route to heterogeneous material systems. However, as hybrid structures continue to be an essential form to couple various material properties and bring forth nanostructures with designable traits, the need for a flexible technique to interface nanomaterials presynthesized in higher quality remains an important challenge. Herein, a technique for laser-guided microcanvas formation by anchoring preformed upconversion nanoparticles at specific sites on a MoS2 monolayer surface is presented. The technique expands the building blocks in laser-produced hybrid structures to include presynthesized nanomaterials. The upconversion microstructures are formed via a microbubble-assisted mechanism, with distinct emission contrast against the background. The proof-of-concept production of a multicolor upconversion microcanvas marks the potential for full-color high-resolution displays while the technique opens up the possibility of fabricating an expandable range of new hybrid structures.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Scanning focused laser beams incident on nanomaterials have provided a nondestructive and facile technique to fabricate micropatterns of a wide variety of hybrid materials. Conventionally, the technique is limited to localized chemical modification or in situ reduction of specific metal ions en route to heterogeneous material systems. However, as hybrid structures continue to be an essential form to couple various material properties and bring forth nanostructures with designable traits, the need for a flexible technique to interface nanomaterials presynthesized in higher quality remains an important challenge. Herein, a technique for laser-guided microcanvas formation by anchoring preformed upconversion nanoparticles at specific sites on a MoS2 monolayer surface is presented. The technique expands the building blocks in laser-produced hybrid structures to include presynthesized nanomaterials. The upconversion microstructures are formed via a microbubble-assisted mechanism, with distinct emission contrast against the background. The proof-of-concept production of a multicolor upconversion microcanvas marks the potential for full-color high-resolution displays while the technique opens up the possibility of fabricating an expandable range of new hybrid structures. |