Abstract
Metal nanoparticles can either quench or enhance the emission of dyes in their vicinity, but the precise measurement and understanding of this effect is still hindered by experimental artifacts, especially for particles in colloidal dispersion. Here, we introduce a new methodology to correct the inner filter effect of the metal on the dye emission. To test the method, we developed new hybrid nanoparticles with a gold core and a silica shell of precise thickness (tuned from 7 to 13 nm), with a high quantum yield perylenediimide dye on the surface. This novel approach effectively avoids fluorescence quenching, allowing us to measure emission enhancements of 5 to 30 times, with no change on the dye fluorescence lifetime. Being able to measure the emission enhancement in dye-metal hybrid nanoparticles in dispersion, free from inner filter and quenching artifacts, offers excellent prospects to guide the development of more efficient fluorescent probes, sensors and photonic devices.
Highlights
The strong electromagnetic field generated at the surface of metal nanostructures upon resonant excitation has been reported to either quench[8,9,10] or enhance[7, 11,12,13,14,15,16,17,18] the photoluminescence of dyes in their vicinity
We believe that inconsistent enhancement results reported for colloidal systems with different metal-dye spacer materials are mostly due to experimental artifacts, such as dye quenching arising from contact with the metal when soft or porous spacers are used, light scattering by the particles, and/or inner filter effects related to light absorption by the metal nanoparticles
The porosity of the silica shell was evaluated by nitrogen adsorption experiments on the silica nanoparticles, with the pore volume (0.0017 cm3/g) being in the range expected for particles produced by the Stöber method[47]
Summary
The strong electromagnetic field generated at the surface of metal nanostructures upon resonant excitation has been reported to either quench[8,9,10] or enhance[7, 11,12,13,14,15,16,17,18] the photoluminescence of dyes in their vicinity. Metal enhanced fluorescence (MEF) has been related to both the increased excitation rate due to the enhancement of the local electrical field experienced by the dye[23, 24], and the electromagnetic coupling of the dye with the metal nanoparticle, allowing the metal to partially transfer the excitation energy non-radiatively to the dyes, and transmit the energy of the dye as radiation to the far field[25, 26]. This behavior results from the interplay of two opposite effects. We believe that inconsistent enhancement results reported for colloidal systems with different metal-dye spacer materials are mostly due to experimental artifacts, such as dye quenching arising from contact with the metal when soft or porous spacers are used, light scattering by the particles, and/or inner filter effects related to light absorption by the metal nanoparticles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
