Relative Quantum Yield Measurements of Coumarin Encapsulated in Core-Shell Silica Nanoparticles

• Published in: Journal of fluorescence Vol. 20; no. 1; pp. 67 - 72
• Main Authors: Herz, Erik, Marchincin, Thomas, Connelly, Laura, Bonner, Daniel, Burns, Andrew, Switalski, Steven, Wiesner, Ulrich
• Format: Journal Article
• Language: English
• Published: Boston Springer US 2010
• Subjects: Absorption; Analytical Chemistry; Arrays; Biochemistry; Biological and Medical Physics; Biomedical and Life Sciences; Biomedicine; Biophysics; Biotechnology; Brightness; Coumarin; Coumarins - chemistry; Covalence; Dyes; Fluorescent Dyes - chemistry; Light; Matrices; Nanoparticles; Nanoparticles - chemistry; Original Paper; Scattering, Radiation; Silicon dioxide; Silicon Dioxide - chemistry; Spectrometry, Fluorescence; Fluorescence; Relative quantum yield; Fluorescent nanoprobe; Nanoparticle; Silica
• ISSN: 1053-0509; 1573-4994
• DOI: 10.1007/s10895-009-0523-6

Fluorescent silica nanoparticles encapsulating organic fluorophores provide an attractive materials platform for a wide array of applications where high fluorescent brightness is required. We describe a class of fluorescent silica nanoparticles with a core-shell architecture and narrow particle size distribution, having a diameter of less than 20 nm and covalently incorporating a blue-emitting coumarin dye. A quantitative comparison of the scattering-corrected relative quantum yield of the particles to free dye in water yields an enhancement of approximately an order of magnitude. This enhancement of quantum efficiency is consistent with previous work on rhodamine dye-based particles. It provides support for the argument that improved brightness over free dye in aqueous solution is a more general effect of covalent incorporation of fluorescent organic dyes within rigid silica nanoparticle matrices. These results indicate a synthetic route towards highly fluorescent silica nanoparticles that produces excellent probes for imaging, security, and sensing applications.