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ultrathin covalent organic framework nanosheet-based photoregulated metal-free oxidase-like nanozyme

Nano Research 2022年第10期15卷 8783-8790页

作者： Yongwu Peng Minchu Huang Liangjun Chen Chengtao Gong Nanjun Li Ying Huang Changming Cheng College of Materials Science and Engineering and College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang 621010China Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics(CAEP)Mianyang 612900China Jiangsu Province Engineering Research Center of Agricultural Breeding Pollution Control and Resource Yancheng Teachers UniversityYancheng 224007China

The exploration of low-cost and metal-free nanozymes with oxidase-mimicking activity is highly desired due to their attractive properties and potential applications.However,it is still challenging and remains unexploited to fully realize oxidase-like nanozyme in the emerging covalent organic frameworks(COFs)due to their polymeric nature and weak photoelectric activity.We herein report the first example of the preparation and oxidase-mimicking activity of novel ultrathin two-dimensional(2D)COF(termed as TTPA-COF)nanosheets.The ultrathin TTPA-COF nanosheets with hexagonal layered structure are constructed from two flexible photoactive(diarylamino)benzene-based linkers,and exhibit remarkable catalytic activity toward the oxidation of 3,3',5,5'-tetramethylbenzidine(TMB)in the presence of O_(2) due to their large specific surface areas and abundant active sites.Moreover,it is worth noting that the nanozyme activity could be regulated by external light irradiation.Based on the oxidasemimicking activity of TTPA-COF nanosheets,a green colorimetric sensor is proposed for the sensitive and selective determination of glutathione(GSH)in a wide linear range of 0.5–40μM with a detection limit of 0.5μM.This work reported here would open new avenues for the exploration of low-cost and high-efficiency nanozymes,as well as extend the application of 2D COF nanosheets in the fields of catalysis and sensing.

关键词： covalent organic framework nanosheets ultrathin photoregulated metal-free oxidase mimics

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ultrathin and Air-Stable Lithium Metal Anodes with Superlong Cycling Life in Ether/Ester-Based Electrolytes

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Energy & Environmental Materials 2023年第4期6卷 289-296页

作者： Chao Luo Zihuan Tang Miaomiao Zhang Xiaoyu Feng Rongjie Luo Qifei Guo Xuming Zhang Biao Gao Zhao Ding Yang Zheng Kaifu Huo The State Key Laboratory of Refractories and Metallurgy Institute of Advanced Materials and NanotechnologyWuhan University of Science and TechnologyWuhan 430081China Wuhan National Laboratory for Optoelectronics(WNLO) School of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan 430074China

ultrathin and air-stable Li metal anodes hold great promise toward high-energy and high-safety Li metal batteries(LMBs).However,the application of LMBs is technically impeded by existing Li metal anodes with large thickness,high reactivity,and poor performance.Here,we developed a novel and scalable approach for the construction of a 10-μm-thick flexible and air-stable Li metal anode by conformally encapsulating Li within a multifunctional VN film.Specifically,the highly lithiophilic VN layer guides a uniform deposition of Li,while abundant and multilevel pores arising from assembly of ultrathin nanosheets enable a spatially confined immersion of metallic Li,thus ensuring an ultrathin and sandwiched Li anode.More impressively,the strong hydrophobicity of VN surface can effectively improve the stability of anode to humid air,whereas the highly conductive framework greatly boosts charge transfer dynamics and enhances Li utilization and high-rate capability.Benefiting from such fascinating features,the constructed Li-VN anode exhibits ultrastable cycling stability in both ether(2500 h)and carbonate(900 h)electrolytes,respectively.Moreover,even exposed to ambient air for 12 h,the anode still can retain~78%capacity,demonstrating excellent air-defendable capability.This work affords a promising strategy for fabricating high-performance,high-safety,and low-cost LMBs.

关键词： air stable highly lithiophilic lithium metal anodes ultrathin VN

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Sub-nanometer ultrathin epitaxy of AlGaN and its application in efficient doping

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Light(Science & Applications) 2022年第4期11卷 654-661页

作者： Jiaming Wang Mingxing Wang Fujun Xu Baiyin Liu Jing Lang Na Zhang Xiangning Kang Zhixin Qin Xuelin Yang Xinqiang Wang Weikun Ge Bo Shen State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking University100871 BeijingChina Nano-optoelectronics Frontier Center of Ministry of Education Peking University100871 BeijingChina Collaborative Innovation Center of Quantum Matter 100871 BeijingChina

Solving the doping asymmetry issue in wide gap semiconductors is a key dificulty and long-standing challenge for device applications.Here,a desorption-tailoring strategy is proposed to juggle the carrier concentration and transport.Specific to the p-doping issue in Al-rich AlGaN,self-assembled p-AlGaN superlattices with an average Al composition of over 50%are prepared by adopting this approach.The hole concentration as high as 8.1×10^(18)cm^(-3)is thus realized at room temperature,which is attributed to the signifcant reduction of effective Mg activation energy to 17.5 meV through modulating the activating path,as well as the highlighted Mg surface-incorporation by an intentional interruption for desorption.More importantly,benefting from the constant ultrathin barrier thickness of only three monolayers via this approach,vertical miniband transport of holes is verifed in the p-AlGaN superlattices,greatly satisfying the demand of hole injection in device application.280 nm deep-ultraviolet light emitting diodes are then fabricated as a demo with the desorption-tailored Al-rich p-AlGaN superlattices,which exhibit a great improvement of the carrier injection efficiency and light extraction efficiency,thus leading to a 55.7%increase of the light output power.This study provides a solution for p-type doping of Al-rich AlGaN,and also sheds light on solving the doping asymmetry issue in general for wide-gap semiconductors.

关键词： AlGaN ultrathin GaN

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Accurate determination of anisotropic thermal conductivity for ultrathin composite film

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Chinese Physics B 2022年第10期31卷 572-577页

作者：朱秋毫彭景凇郭潇张如轩江雷程群峰梁文杰 Beijing National Center for Condensed Matter Physics Beijing Key Laboratory for Nanomaterials and NanodevicesInstitute of PhysicsChinese Academy of Sciences(CAS)Beijing 100190China CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China School of Chemistry Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of EducationBeijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing 100191China Songshan Lake Materials Laboratory Dongguan 523808China

Highly anisotropic thermal conductive materials are of significance in thermal management applications. However,accurate determination of ultrathin composite thermal properties is a daunting task due to the tiny thermal conductance,severely hindering the further exploration of novel efficient thermal management materials, especially for size-confined environments. In this work, by utilizing a hybrid measuring method, we demonstrate an accurate determination of thermal properties for montmorillonite/reduced graphene oxide(MMT/r GO) composite film with a thickness range from 0.2 μm to2 μm. The in-plane thermal conductivity measurement is realized by one-dimensional(1D) steady-state heat conduction approach while the cross-plane one is achieved via a modified 3ω method. As-measured thermal conductivity results are cross-checked with different methods and known materials, revealing the high measurement accuracy. A high anisotropic ratio of 60.5, independent of composite thickness, is observed in our measurements, further ensuring the negligible measurement error. Notably, our work develops an effective approach to the determination of ultrathin composite thermal conductivity, which may promote the development of ultrathin composites for potential thermal-related applications.

关键词： ultrathin composite film thermal conductivity anisotropic ratio

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Diffraction-limited imaging with monolayer 2D material-based ultrathin flat lenses

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Light(Science & Applications) 2020年第1期9卷 696-706页

作者： Han Lin Zai-Quan Xu Guiyuan Cao Yupeng Zhang Jiadong Zhou Ziyu Wang Zhichen Wan Zheng Liu Kian Ping Loh Cheng-Wei Qiu Qiaoliang Bao Baohua Jia Centre for Translational Atomaterials Faculty of ScienceEngineering and TechnologySwinburne University of TechnologyP.O.Box 218HawthornVIC 3122Australia Department of Materials Science and Engineering ARC Centre of Excellence in Future Low-Energy Electronics Technologies(FLEET)Monash UniversityWellington RoadClaytonVIC 3800Australia School of Mathematical and Physical Sciences Faculty of ScienceUniversity of Technology Sydney15 BroadwayUltimoNSW 2007Australia Institute of Microscale Optoelectronics Lab of Artificial Microstructure for OptoelectronicsShenzhen University518000 ShenzhenChina School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Department of Chemistry National University of SingaporeSingapore 117543Singapore Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore The Australian Research Council(ARC)Industrial Transformation Training Centre in Surface Engineering for Advanced Materials(SEAM) Swinburne University of TechnologyP.O.Box 218HawthornVIC 3122Australia

ultrathin flat optics allow control of light at the subwavelength scale that is unmatched by traditional refractive optics.To approach the atomically thin limit,the use of 2D materials is an attractive possibility due to their high refractive indices.However,achievement of diffraction-limited focusing and imaging is challenged by their thickness-limited spatial resolution and focusing efficiency.Here we report a universal method to transform 2D monolayers into ultrathin flat lenses.Femtosecond laser direct writing was applied to generate local scattering media inside a monolayer,which overcomes the longstanding challenge of obtaining sufficient phase or amplitude modulation in atomically thin 2D materials.We achieved highly efficient 3D focusing with subwavelength resolution and diffractionlimited imaging.The high focusing performance even allows diffraction-limited imaging at different focal positions with varying magnifications.Our work paves the way for downscaling of optical devices using 2D materials and reports an unprecedented approach for fabricating ultrathin imaging devices.

关键词： ultrathin scattering optics

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Detour-phased perovskite ultrathin planar lens using direct femtosecond laser writing

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Photonics Research 2022年第12期10卷 2768-2777页

作者： WENKAI YANG LIGE LIU DASHAN DONG XIN ZHANG HAN LIN YUNKUN WANG HONG YANG YUNAN GAO HAIZHENG ZHONG BAOHUA JIA KEBIN SHI State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices School of Materials Sciences and EngineeringBeijing Institute of TechnologyBeijing 100081China School of Science RMIT UniversityMelbourne 3000VICAustralia Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China

Perovskite-enabled optical devices have drawn intensive interest and have been considered promising candidates for integrated optoelectronic systems.As one of the important photonic functions,optical phase modulation previously was demonstrated with perovskite substrate and complex refractive index engineering with laser scribing.Here we report on the new scheme of achieving efficient phase modulation by combining detour phase design with 40 nm ultrathin perovskite films composed of nanosized crystalline particles.Phase modulation was realized by binary amplitude patterning,which significantly simplifies the fabrication process.Perovskite nanocrystal films exhibit significantly weak ion migration effects under femtosecond laser writing,resulting in smooth edges along the laser ablated area and high diffractive optical quality.Fabrication of a detour-phased perovskite ultrathin planar lens with a diameter of 150μm using femtosecond laser scribing was experimentally demonstrated.A high-performance 3D focus was observed,and the fabrication showed a high tolerance with different laser writing powers.Furthermore,the high-quality imaging capability of perovskite ultrathin planar lenses with a suppressed background was also demonstrated.

关键词： laser ultrathin femtosecond

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Engineering an ultrathin amorphous TiO2 layer for boosting the weatherability of TiO2 pigment with high lightening power

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Chinese Journal of Chemical Engineering 2019年第11期27卷 2825-2834页

作者： Yangyang Yu Kejing Wu Shiyu Lu Kui Ma Shan Zhong Hegui Zhang Yingming Zhu Jing Guo Hairong Yue Changjun Liu Siyang Tang Bin Liang Low-Carbon Technology and Chemical Reaction Engineering Laboratory School of Chemical EngineeringSichuan UniversityChengdu 610065China Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu 610207China Institute for Clean Energy&Advanced Materials Faculty of Materials and EnergySouthwest UniversityChongqing 400715China Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering North University of ChinaTaiyuan 030051China

TiO2 pigments are typically coated with inert layers to suppress the photocatalytic activity and improve the weatherability. However, the traditional inert layers have a lower refractive index compared to TiO2, and therefore reduce the lightening power of TiO2. In the present work, a uniform, amorphous, 2.9-nm-thick TiO2 protective layer was deposited onto the surface of anatase TiO2 pigments according to pulsed chemical vapor deposition at room temperature, with Ti Cl4 as titanium precursor. Amorphous TiO2 coating layers exhibited poor photocatalytic activity, leading to a boosted weatherability. Similarly, this coating method is also effective for TiO2 coating with amorphous SiO2 and SnO2 layers. However, the lightening power of amorphous TiO2 layer is higher than those of amorphous SiO2 and SnO2 layers. According to the measurements of photoluminescence lifetime, surface photocurrent density, charge-transfer resistance, and electron spin resonance spectroscopy, it is revealed that the amorphous layer can prevent the migration of photogenerated electrons and holes onto the surface, decreasing the densities of surface electron and hole, and thereby suppress the photocatalytic activity.

关键词： TiO2 pigments Pulsed chemical vapor deposition ultrathin layer Weatherability Lightening power Photocatalytic suppression mechanism

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Early gastric cancer diagnostic ability of ultrathin endoscope loaded with laser light source

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World Journal of Gastroenterology 2019年第11期25卷 1378-1386页

作者： Takuto Suzuki Yoshiyasu Kitagawa Rino Nankinzan Taketo Yamaguchi Department of Endoscopy Chiba Cancer Center Department of Gastroenterology Chiba Cancer Center

BACKGROUND Conventionally, the low luminous intensity, low image resolution, and difficulty in operation have been reported with the ultrathin endoscope. However, it has markedly advanced recently. The improvement of the diagnostic ability is expected.AIM To compare the early gastric cancer diagnostic ability of an ultrathin endoscope loaded with a laser light source and that of the conventional endoscope.METHODS The target subjects were 375 consecutive patients who underwent endoscopy at our hospital for post-endoscopic submucosal dissection follow-up of gastric cancer from January to August 2018. During endoscopy, the ultrathin endoscope was used in 140 patients(37.3%), and the conventional endoscope was used in235 patients(62.7%). Patient background was adjusted using the propensity score matching method, and gastric cancer detection ability was evaluated in the two groups.RESULTS The gastric cancer detection rate was 7.8% in the ultrathin endoscope group and7.0% in the conventional endoscope group, and the mean intragastric observation time was 4.1 ± 1.7 min in the ultrathin endoscope group and 4.1 ± 1.9 min in the conventional endoscope group, showing no significant differences between the groups. Moreover, the biopsy implementation rate was 31.8% in the ultrathin endoscope group and 41.1% in the conventional endoscope group, and the biopsy prediction rate was 17.9% and 13.2%, respectively, showing no significant differences between the groups.CONCLUSION The gastric cancer diagnostic ability of the ultrathin endoscope loaded with a laser light source was comparable to that of the conventional endoscope. The observation time was also comparable. Thus, endoscopy using the ultrathin endoscope loaded with the laser light source would be the first option in screening examinations of gastric cancer due to its low invasion.

关键词： Conventional endoscope Gastric cancer Laser light source Screening ultrathin endoscope

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Flexible ultrathin all-solid-state supercapacitors

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Rare Metals 2018年第6期37卷 536-542页

作者： Rui Wang Qing-Rong Wang Min-Jie Yao Ke-Na Chen Xin-Yu Wang Li-Li Liu Zhi-Qiang Niu Jun Chen Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) College of Chemistry Nankai University Tianjin Key Laboratory for Photoelectric Materials and Devices School of Materials Science and Engineering Tianjin University of Technology

The flexible ultrathin all-solid-state supercapacitors with good electrochemical and mechanical performance were fabricated by the facile methods. The singlewall carbon nanotubes （SWCNTs）-polyaniline （PANI） film electrodes and poly（vinyl alcohol）（PVA）/H3PO4 electrolyte film were prepared by spray-printing and spincoating strategies, respectively. Thus, the thickness of a supercapacitor is only 8.4 μm. When the mass ratio of SWCNT to PANI is 1：1, the tensile strength and Young＇s modulus of the electrode are 10.9 and 655 MPa, respectively. The interior contact resistance of the supercapacitors based on this electrode is only 15-30 Ω. Furthermore, the specific capacitance of this electrode can reach about 355.5 F·g^-1, and the supercapacitor based on this electrode maintains 87.2% of its initial specific capacitance over 5000 charging/discharging cycles. Moreover, the supercapacitor shows an excellent electrochemical stability at different bending states. Therefore, the all-solid-state supercapacitors prepared by our strategies would meet the demands of wearable, lightweight, and compact energy storage devices.

关键词： Supercapacitor ultrathin Spray printing Carbon nanotube

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Facile synthesis of large-area ultrathin two-dimensional supramolecular nanosheets in water

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Nano Research 2020年第3期13卷 868-874页

作者： Bojian Hu Peiyi Wu State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceLaboratory far Advanced MaterialsFudan UniversityShanghai 200433China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of ChemistryChemical Engineering and BiotechnologyCenter for Advanced Low-Dimension MaterialsDonghua UniversityShanghai 201620China

Synthesizing large-area ultrathin two-dimensional(2D)nanostructures in aqueous media has received considerable increasing attention but remains a big challenge.Herein,we report a facile method for the synthesis of two unprecedented large-area ultrathin 2D supramolecular nanosheets via ionic self-assembly in water.Upon consideration of electrostatic interaction and repulsive effect,deprotonated tetrakis(4-carboxyphenyl)porphyrin(TCPP)or Fe(III)tetra(4-carboxyphenyl)porphine chloride(TCPP(Fe))as connection vertex and protonated bis(2-dimethylaminoethyl)ether(BDMAEE)unit as bridging edge connect with each other to form few-layer 2D nanosheet with a thickness of^1.8–1.9 nm,while the lateral size can close to one hundred micrometers.Moreover,the well-dispersed 2D TCPP(Fe)-BDMAEE with heme-like active center displays intrinsic peroxidase-like catalytic activity,which can be used to detect hydrogen peroxide.The present facile strategy highlights new opportunities in constructing large-area ultrathin 2D supramolecular nanomaterials and paves the avenue to expand their potential applications.

关键词： large-area ultrathin two-dimensional supramolecular nanosheets peroxidase-like catalytic activity

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