Supporting Information. Tuning and Switching a Plasmonic Quantum Dot. Sandwich in a Nematic Line Defect

Transcription

1 Supporting Information Tuning and Switching a Plasmonic Quantum Dot Sandwich in a Nematic Line Defect Haridas Mundoor, Ghadah H. Sheetah, Sungoh Park, Paul J. Ackerman, Ivan I. Smalyukh * and Jao van de Lagemaat **. Department of Physics, University of Colorado, Boulder, CO 80309, USA. Materials Science and Engineering Program, University of Colorado, Boulder, CO 80309, USA. Soft Materials Research Center and Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, CO 80309, USA. Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, CO 80309, USA. National Renewable Energy Laboratory, Golden, Colorado 80401, USA.

2 Figure S1: Fluorescence decay curves of a QD particle trapped inside the line defect (black) and a QD particle sandwiched between two GNRs forming a dimer structure based on multiple measurements on GNR-QD assemblies (colored). Black curve represents a typical decay curve for a QD particle without GNR. τ 1 (ns) τ (ns) QD QD-Au Table S1: The lifetime values extracted by fitting a double exponential equation to the fluorescence decay curves presented in Figure S1 above.

3 Figure S: Fluorescence spectra of a single QD in line defect without GNR (a) and with GNRs showing a blueshifted (b) and redshifted (c) spectra.

4 Figure S3: Simulated extinction spectra of a single GNR particle (black curve) and two GNR particles forming a sandwich structure (red curve) in the LC line defect. (b) Plot of LSPR peak positions vs. end-to-end separation between the gold cores of two GNRs located in the LC line defect calculated based on DDA ( ) and COMSOL Multiphysics ( ). Variations of maximum electric field enhancement wavelength () with end-to-end separation between the gold cores of two GNRs in the sandwich structure, calculated based on the electromagnetic simulations using COMSOL Multiphysics. Estimation of surface temperature of GNR particle during laser tweezer manipulation. Approximate estimate of the increase in temperature at the surface of silica layer of the GNR particles when manipulated with a laser trap can be calculated by the equation: T S = Φr3 3λh Where r is the radius of the gold core of GNR particles, h is the radius of the silica coated particle, and λ is the thermal conductivity of silica. Φ=ησ/V is the heat absorbed by the particle per unit volume, where η is the incident laser intensity, σ is the absorption cross section of the particle at 1064 nm and V is the volume of the particle. For 7 mw laser power, the temperature increase at the surface of the silica layer of the GNR particles is estimated to be ~ o C.

5 Estimation of van der Waals attraction between the GNRs in LC defect. The total interaction potential between two GNRs in line defect can be represented as sum of pair potential uel due to the repulsive elastic and uvdw due to the attractive van der Waals interaction potential. u(r cc ) = u el (r cc ) + u vdw (r cc ) The van der Waals potential between the GNRs in the line defect can be estimated using the relation, u vdw ( r cc A lnr lnr l ) ln 6 4lnr H 4 nr Where lnr is the length of the nanorods, AH = J is the Hamaker constant and is the interparticle distance. The van der Waals potential uvdw() between the GNRs at the distances we studied in Figure b, ( = 1 μm) is many orders of magnitude smaller ( ~ 10-6 kbt) than the measured elastic potential (00 kbt). At smaller distances between the GNRs such as the one in sandwich structure, the van der Waals potential increases to ~ 5-10 kbt.