We have investigated the self-assembly and light emission properties of organic α- sexithiophene （α-6T） molecules on Ag（100） under different coverage by scanning tunneling microscopy （STM）. At very low coverag...We have investigated the self-assembly and light emission properties of organic α- sexithiophene （α-6T） molecules on Ag（100） under different coverage by scanning tunneling microscopy （STM）. At very low coverage, the α-6T molecules form a unique enantiomer by grouping four molecules into a windmill supermolecular structure. As the coverage is increased,α-6T molecules tend to pack side by side into a denser stripe structure. Further increase of the coverage will lead to the layer-by-layer growth of molecules on Ag（100） with the lower-layer stripe pattern serving as a template. Molecular fluorescence for α-6T molecules on Ag（100） at a coverage of five monolayers has been detected by light excitations, which indicates a well decoupled electronic states for the top-layer α-6T molecules. However, the STM induced luminescent spectra for the same sample reveal only plasmonic-like emission. The absence of intramolecular fluorescence in this case suggests that the electronic decoupling is not a sufficient condition for generating photon emission from molecules. For intramolecular fluorescence to occur, the orientation of the dynamic dipole moment of molecules and the energy-level alignment at the molecule-metal interface are also important so that molecules can be effectively excited through efficient dipolar coupling with local plasmons and by injecting holes into the molecules.展开更多
We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine(TDBC)molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells.When TDBC mo...We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine(TDBC)molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells.When TDBC molecules are deposited on pure Ag nanoprisms or Ag@Au hollow nanoshells with the plasmonic resonance peak,matching very closely with the absorption band of TDBC J-aggregates,obvious Rabi splitting can be observed due to the strong coupling regime.Meanwhile,the photoluminescence intensity decreased with the increasing of the temperature,verifying the decreasing plasmon-exciton coupling interaction in the higher temperature.Our experimental results are coincident with the simulation results calculated by finite-difference time-domain method.展开更多
We report the dispersion and scanning tunneling microscopy （STM） characterization of iso- lated Au-CdSe nanohybrids on atomically fiat Au（111） through surface modifications. The top terminal groups of spacer molec...We report the dispersion and scanning tunneling microscopy （STM） characterization of iso- lated Au-CdSe nanohybrids on atomically fiat Au（111） through surface modifications. The top terminal groups of spacer molecules self-assembled on the surface are found critical for locking the nanohybrids into a well-separated state. The STM results indicate that both thiol and carboxylic terminals are effective in this aspect by making strong interaction with the Au portions of the nanohybrids. An argon ion sputtering technique is also proposed to clean up organic contaminants on the surface for improved STM imaging of individual Au-CdSe nanohybrids. These observations help to enrich technical approaches to dispersing individual nanostructures on the surface and provide opportunities to explore their local electroluminescent and energy transfer properties at the nanoscale.展开更多
A hybrid material of carbon microspheres（CMSs） with Ag decoration（Ag/CMSs） was developed.Poly（3-hexylthiophene）：Ag/CMSs composite film was prepared by spin-coating.Scanning electron microscopy,transmission elec...A hybrid material of carbon microspheres（CMSs） with Ag decoration（Ag/CMSs） was developed.Poly（3-hexylthiophene）：Ag/CMSs composite film was prepared by spin-coating.Scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectrometry,X-ray diffraction,thermogravimetric analysis and cyclic voltammetry were employed to analyze the morphologies,structures,thermal properties and energy levels of Ag/CMSs.The optical property of the composite films was characterized by ultraviolet-visible spectrophotometry and fluorescent spectrometry.The results indicate that silver nanoparticles（AgNPs,d = 10-20 nm） are distributed on the surface of CMSs.LUMO and HOMO energy levels of Ag/CMSs are-3.97 and-5.52 e V,below the vacuum energy level,respectively,indicating that it is feasible to use Ag/CMSs as an electron acceptor.Ag NPs are blended into the active layer to trigger localized surface plasmon resonance,and consequently enhance light harvesting.The coupling of surface plasmons and excitons increased the probability of exciton dissociation.展开更多
基金Author to whom correspondence should be addressed. E-mail： zcdong@ustc.edu.cn, FAX： ＋86-551-3600103 This work was supported by the National Basic Research Program of China （No.2006CB922003 and No.2011CB921402）, the Chinese Academy of Sciences （No.KJCX2.YW.H06）, and the National Natural Science Foundation of China （No.91021004, No.10574117, and No.10974186）.
文摘We have investigated the self-assembly and light emission properties of organic α- sexithiophene （α-6T） molecules on Ag（100） under different coverage by scanning tunneling microscopy （STM）. At very low coverage, the α-6T molecules form a unique enantiomer by grouping four molecules into a windmill supermolecular structure. As the coverage is increased,α-6T molecules tend to pack side by side into a denser stripe structure. Further increase of the coverage will lead to the layer-by-layer growth of molecules on Ag（100） with the lower-layer stripe pattern serving as a template. Molecular fluorescence for α-6T molecules on Ag（100） at a coverage of five monolayers has been detected by light excitations, which indicates a well decoupled electronic states for the top-layer α-6T molecules. However, the STM induced luminescent spectra for the same sample reveal only plasmonic-like emission. The absence of intramolecular fluorescence in this case suggests that the electronic decoupling is not a sufficient condition for generating photon emission from molecules. For intramolecular fluorescence to occur, the orientation of the dynamic dipole moment of molecules and the energy-level alignment at the molecule-metal interface are also important so that molecules can be effectively excited through efficient dipolar coupling with local plasmons and by injecting holes into the molecules.
基金supported by the National Key R&D Program of China(No.2017YFA0303403)the National Natural Science Foundation of China(Nos.11874015,12074012,11674099+2 种基金11722431)the Shanghai International CooperationProject(No.16520710600)the Program of Introducing Talents of Discipline to Universities(No.B12024)。
文摘We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine(TDBC)molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells.When TDBC molecules are deposited on pure Ag nanoprisms or Ag@Au hollow nanoshells with the plasmonic resonance peak,matching very closely with the absorption band of TDBC J-aggregates,obvious Rabi splitting can be observed due to the strong coupling regime.Meanwhile,the photoluminescence intensity decreased with the increasing of the temperature,verifying the decreasing plasmon-exciton coupling interaction in the higher temperature.Our experimental results are coincident with the simulation results calculated by finite-difference time-domain method.
文摘We report the dispersion and scanning tunneling microscopy （STM） characterization of iso- lated Au-CdSe nanohybrids on atomically fiat Au（111） through surface modifications. The top terminal groups of spacer molecules self-assembled on the surface are found critical for locking the nanohybrids into a well-separated state. The STM results indicate that both thiol and carboxylic terminals are effective in this aspect by making strong interaction with the Au portions of the nanohybrids. An argon ion sputtering technique is also proposed to clean up organic contaminants on the surface for improved STM imaging of individual Au-CdSe nanohybrids. These observations help to enrich technical approaches to dispersing individual nanostructures on the surface and provide opportunities to explore their local electroluminescent and energy transfer properties at the nanoscale.
基金Funded by the National Natural Science Foundation of China(21176169)the Shanxi Provincial Key Innovative Research Team in Science and Technology(2012041011,2015013002-10)+1 种基金the International Science&Technology Cooperation Program of China(2012DFR50460)the Research Project Supported by Shanxi Scholarship Council of China(2012-038)
文摘A hybrid material of carbon microspheres（CMSs） with Ag decoration（Ag/CMSs） was developed.Poly（3-hexylthiophene）：Ag/CMSs composite film was prepared by spin-coating.Scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectrometry,X-ray diffraction,thermogravimetric analysis and cyclic voltammetry were employed to analyze the morphologies,structures,thermal properties and energy levels of Ag/CMSs.The optical property of the composite films was characterized by ultraviolet-visible spectrophotometry and fluorescent spectrometry.The results indicate that silver nanoparticles（AgNPs,d = 10-20 nm） are distributed on the surface of CMSs.LUMO and HOMO energy levels of Ag/CMSs are-3.97 and-5.52 e V,below the vacuum energy level,respectively,indicating that it is feasible to use Ag/CMSs as an electron acceptor.Ag NPs are blended into the active layer to trigger localized surface plasmon resonance,and consequently enhance light harvesting.The coupling of surface plasmons and excitons increased the probability of exciton dissociation.
