Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: [DS] Plasmonics and Nanophotonics (jointly with HL and O)
O 58.7: Vortrag
Mittwoch, 16. März 2011, 18:45–19:00, GER 38
A self-assembly route to mesoporous Bragg reflectors — •Stefan Guldin1, Matthias Kolle1, Morgan Stefik3, Richard Langford1, Dominik Eder2, Ulrich Wiesner3, and Ullrich Steiner1 — 1Physics Department, Cavendish Laboratory, University of Cambridge, UK — 2Materials Science Department, University of Cambridge, UK — 3Materials Science Department, Cornell University, Ithaca, NY, USA
Mesoporous distributed Bragg reflectors (MDBRs) consist of a periodic lattice of alternating high and low refractive index, while exhibiting porosity on the sub-optical length scale. MDBRs have great potential as sensing materials in biology and chemistry, as adsorption and desorption of gas phase molecules lead to reversible changes in the refractive index of the stack. Optoelectronics is another promising field of applications. MDBRs can be used as light harvesting element in excitonic solar cells. When infiltrated with light emitting polymers, MDBRs have exhibited distributed feedback lasing.
We present a new route for the fabrication of MDBRs which relies on the self-assembling properties of the block copolymer PI-b-PEO in combination with sol-gel chemistry to finely tune porosity and pore size in the resulting inorganic material. Stacking-up multiple layers of alternating refractive index results in a fast and reliable assembly of a continuous network with well defined interfaces. The outcome are MDBRs of high quality optical properties even when built from a single material, in our case TiO2.