We acknowledge support from the Italian Ministry of Instruction, University and Research through projects PRIN 2004 and FIRB 2001.
Colloidal Photonic Crystals Doped with Gold Nanoparticles: Spectroscopy and Optical Switching Properties†
Article first published online: 23 AUG 2007
Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 17, Issue 15, pages 2779–2786, October, 2007
How to Cite
Morandi, V., Marabelli, F., Amendola, V., Meneghetti, M. and Comoretto, D. (2007), Colloidal Photonic Crystals Doped with Gold Nanoparticles: Spectroscopy and Optical Switching Properties. Adv. Funct. Mater., 17: 2779–2786. doi: 10.1002/adfm.200600764
- Issue published online: 11 OCT 2007
- Article first published online: 23 AUG 2007
- Manuscript Revised: 31 JAN 2007
- Manuscript Received: 21 AUG 2006
- Italian Ministry of Instruction, University and Research. Grant Numbers: PRIN 2004, FIRB 2001
- Optical switches;
- Photonic crystals
Polystyrene artificial opals with few gold nanoparticles (AuNp) embedded in the interstices (doping) are grown by using the meniscus technique starting from a mixed suspension of microspheres and AuNp. Samples having different sphere diameters and nanoparticle loads have been prepared. Their reflectance spectra clearly show a dramatic bathochromic shift of the photonic stop band (up to 1400 cm–1) and a reduction of its full width half maximum, due to an increase of the effective refractive index of about 8 % with respect to bare opals, which is accounted for by analytical theoretical models. Reflectance spectra do not show any direct evidence of AuNp absorption even at the higher AuNp doping level. Nanosecond transient absorption measurements on these systems indicate that a variation of transmission (optical switching) of about 150 % is observed for AuNp doped opals upon photoexcitation with 9 ns laser pulses at 532 nm. No switching is instead observed for bare opals.