Titanium dioxide(TiO_(2))has been extensively investigated as a photocatalyst for water splitting to produce H2.However,an overall water splitting by using anatase TiO_(2) is extremely difficult due to the short lifet...Titanium dioxide(TiO_(2))has been extensively investigated as a photocatalyst for water splitting to produce H2.However,an overall water splitting by using anatase TiO_(2) is extremely difficult due to the short lifetime of holes.In this work,we propose that a surface energy decrease from{001}to{101}of anatase TiO_(2) is able to drive an epitaxial growth.A novel anatase TiO_(2) homostructure has been successfully synthesized via a facile hydrothermal route,where{101}semi-pyramid nanoparticles epitaxially grew on the both sides of the{001}nanosheets.The epitaxial relationship between the nanoparticles and the nanosheets has been characterized to be{001}//{001}of anatase TiO_(2).For the first time,it is interesting to find that the homostructure with 12 wt%of{101}semi-pyramid can significantly improve the H2 evolution rate by nearly 5 times compared to the pure nanosheets under the ultraviolet irradiation.More importantly,such homostructure enables 10.78μmol g-1h-1 of O_(2) production whereas the pure nanosheets cannot evolve detectable O_(2) gas.Meanwhile,the time-resolved photoluminescence analysis indicates that the mean lifetime of the holes is increased from 2.20 ns of the nanosheets to 3.59 ns of the homostructure,accounting for the observed overall water splitting.The findings suggest that constructing a homostructure by a surface energy strategy could be promising towards overall water splitting,which may be applicable to other photocatalytic materials.展开更多
Complex oxide thin films exhibit intriguing phenomena due to the coupling between multiple degrees of freedom through interfacial structural engineering.Atomic tailoring of structural parameters determines unique band...Complex oxide thin films exhibit intriguing phenomena due to the coupling between multiple degrees of freedom through interfacial structural engineering.Atomic tailoring of structural parameters determines unique band structure and phonon modes,regulating emergent magnetic and electrical properties of oxide films.However,the construction of different strained and oriented domains in one intact oxide thin film is impossible using conventional means.Here we report the fabrication and quantitative structural analysis of La_(0.7)Sr_(0.3)MnO_(3)(LSMO)homostructures assisted by atomic-flat freestanding membranes.Pristine substrates and suspended membranes regulate the epitaxial strain and orientation of subsequently grown films.Our results demonstrate an ultrathin transition layer(~4 atomic layers)between freestanding membranes and LSMO films is formed due to the strain relaxation.This work offers a simple and scalable methodology for fabricating unprecedented innovative functional oxide homostructures through artificially controlled synthesis routes.展开更多
Complicated multilevel micro/nanostructures have attracted great attention as essential basic components of integrated optoelectronic devices.However,precise synthesis of these well-designed micro/nanostructures is st...Complicated multilevel micro/nanostructures have attracted great attention as essential basic components of integrated optoelectronic devices.However,precise synthesis of these well-designed micro/nanostructures is still a major challenge.In this report,a series of near-infrared emissive multilevel branched organic microwires with different integrated levels are successfully fabricated for the first time by a facile self-assembly approach based on our well designed and synthesized(2E,2′E)-1,1′-(1,5-dihydroxynaphthalene-2,6-diyl)bis(3-(4-(dimethylamino)phenyl)prop-2-en-1-one)(DHNBP).The growth mechanism is attributed to lattice matching between(100)and(010)crystal planes,with an interplanar spacing mismatch rate as low as 5.3%.Benefiting from the uniaxial oriented molecular packing mode of the crystal,the well-prepared microwires have outstanding optical properties.More significantly,the branched structures can work as optical logic gates and optical signal processors.Therefore,this synthesis method for multilevel branched microwires will potentially facilitate the development of organic integrated optoelectronics.展开更多
Recently,the discovery of a variety of moiré-related properties in the twisted vertical stacking of two different monolayers has attracted considerable attention.The introduction of small twist angles in transiti...Recently,the discovery of a variety of moiré-related properties in the twisted vertical stacking of two different monolayers has attracted considerable attention.The introduction of small twist angles in transition metal dichalcogenide(TMD)heterostructures leads to the emergence of moirépotentials,which provide a fascinating platform for the study of strong interactions of electrons.While there has been extensive research on moiréexcitons in twisted bilayer superlattices,the capture and study of moiréexcitons in homostructure superlattices with layer-coupling effects remain elusive.Here,we present the observation of moiréexcitons in the twisted 1L-WSe_(2)/1L-WSe_(2)and 1L-WSe_(2)/2L-WSe_(2)homostructures with various layer-coupling interactions.The results reveal that the moirépotential increases(~260%)as the number of underlying layers decreases,indicating the effect of layer coupling on the modulation of the moirépotential.The effects of the temperature and laser power dependence as well as valley polarization on moiréexcitons were further demonstrated,and the crucial spectral features observed were explained.Our findings pave the way for exploring quantum phenomena and related applications of quantum information.展开更多
基金the National Natural Science Foundation of China[Nos.U1809217 and 51472218]State Key Laboratory of Crystal Materials(KF1807)Fundamental Research Funds for the Central Universities[2019XZZX005-4-01]。
文摘Titanium dioxide(TiO_(2))has been extensively investigated as a photocatalyst for water splitting to produce H2.However,an overall water splitting by using anatase TiO_(2) is extremely difficult due to the short lifetime of holes.In this work,we propose that a surface energy decrease from{001}to{101}of anatase TiO_(2) is able to drive an epitaxial growth.A novel anatase TiO_(2) homostructure has been successfully synthesized via a facile hydrothermal route,where{101}semi-pyramid nanoparticles epitaxially grew on the both sides of the{001}nanosheets.The epitaxial relationship between the nanoparticles and the nanosheets has been characterized to be{001}//{001}of anatase TiO_(2).For the first time,it is interesting to find that the homostructure with 12 wt%of{101}semi-pyramid can significantly improve the H2 evolution rate by nearly 5 times compared to the pure nanosheets under the ultraviolet irradiation.More importantly,such homostructure enables 10.78μmol g-1h-1 of O_(2) production whereas the pure nanosheets cannot evolve detectable O_(2) gas.Meanwhile,the time-resolved photoluminescence analysis indicates that the mean lifetime of the holes is increased from 2.20 ns of the nanosheets to 3.59 ns of the homostructure,accounting for the observed overall water splitting.The findings suggest that constructing a homostructure by a surface energy strategy could be promising towards overall water splitting,which may be applicable to other photocatalytic materials.
基金the National Key Basic Research Program of China(No.2020YFA0309100)the National Natural Science Foundation of China(Nos.51971025,12034002,11974390,U22A20263,and 52250308)+2 种基金the Beijing Natural Science Foundation(No.2212034)the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology(No.HT-CSNS-DG-CD-0080/2021)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(No.XDB33030200).
文摘Complex oxide thin films exhibit intriguing phenomena due to the coupling between multiple degrees of freedom through interfacial structural engineering.Atomic tailoring of structural parameters determines unique band structure and phonon modes,regulating emergent magnetic and electrical properties of oxide films.However,the construction of different strained and oriented domains in one intact oxide thin film is impossible using conventional means.Here we report the fabrication and quantitative structural analysis of La_(0.7)Sr_(0.3)MnO_(3)(LSMO)homostructures assisted by atomic-flat freestanding membranes.Pristine substrates and suspended membranes regulate the epitaxial strain and orientation of subsequently grown films.Our results demonstrate an ultrathin transition layer(~4 atomic layers)between freestanding membranes and LSMO films is formed due to the strain relaxation.This work offers a simple and scalable methodology for fabricating unprecedented innovative functional oxide homostructures through artificially controlled synthesis routes.
基金financially supported by the National Natural Science Foundation of China(21971185,51821002)China Postdoctoral Science Foundation(2020M681707)+1 种基金the Collaborative Innovation Center of Suzhou Nano Science and Technology(CIC-Nano)the"111"Project of the State Administration of Foreign Experts Affairs of China。
文摘Complicated multilevel micro/nanostructures have attracted great attention as essential basic components of integrated optoelectronic devices.However,precise synthesis of these well-designed micro/nanostructures is still a major challenge.In this report,a series of near-infrared emissive multilevel branched organic microwires with different integrated levels are successfully fabricated for the first time by a facile self-assembly approach based on our well designed and synthesized(2E,2′E)-1,1′-(1,5-dihydroxynaphthalene-2,6-diyl)bis(3-(4-(dimethylamino)phenyl)prop-2-en-1-one)(DHNBP).The growth mechanism is attributed to lattice matching between(100)and(010)crystal planes,with an interplanar spacing mismatch rate as low as 5.3%.Benefiting from the uniaxial oriented molecular packing mode of the crystal,the well-prepared microwires have outstanding optical properties.More significantly,the branched structures can work as optical logic gates and optical signal processors.Therefore,this synthesis method for multilevel branched microwires will potentially facilitate the development of organic integrated optoelectronics.
基金the National Natural Science Foundation of China(No.61775241)Hunan province key research and development project(No.2019GK2233)+9 种基金Hunan Provincial Science Fund for Distinguished Young Scholars(No.2020JJ2059)the Youth Innovation Team(No.2019012)of CSUthe Science and Technology Innovation Basic Research Project of Shenzhen(No.JCYJ20190806144418859)the National Natural Science Foundation of China(Nos.62090035 and U19A2090)the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)support of the High-Performance Complex Manufacturing Key State Lab Project,Central South University(No.ZZYJKT2020-12)the Australian Research Council(ARC Discovery Project,No.DP180102976)the National Natural Science Foundation of China(No.11974387)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB33000000)the National Key Research and Development Program of China(No.2020YFA0711502).
文摘Recently,the discovery of a variety of moiré-related properties in the twisted vertical stacking of two different monolayers has attracted considerable attention.The introduction of small twist angles in transition metal dichalcogenide(TMD)heterostructures leads to the emergence of moirépotentials,which provide a fascinating platform for the study of strong interactions of electrons.While there has been extensive research on moiréexcitons in twisted bilayer superlattices,the capture and study of moiréexcitons in homostructure superlattices with layer-coupling effects remain elusive.Here,we present the observation of moiréexcitons in the twisted 1L-WSe_(2)/1L-WSe_(2)and 1L-WSe_(2)/2L-WSe_(2)homostructures with various layer-coupling interactions.The results reveal that the moirépotential increases(~260%)as the number of underlying layers decreases,indicating the effect of layer coupling on the modulation of the moirépotential.The effects of the temperature and laser power dependence as well as valley polarization on moiréexcitons were further demonstrated,and the crucial spectral features observed were explained.Our findings pave the way for exploring quantum phenomena and related applications of quantum information.
