Memoirs of the Graduate Schools of Engineering and System Informatics Kobe University, No. 7, pp. 17-20, 2015
Hiroshi SUGIMOTO1, Minoru FUJII1, Björn M. Reinhard2, Luca Dal Negro3
1Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University
2Department of Chemistry & Photonics Center, Boston University
3Department of Electrical and Computer Engineering & Photonics Center, Boston University
(Received January 28, 2016; Accepted January 28, 2016; Online published May 16, 2016)
Keywords: Biophotonics, Silicon quantum dots, Surface plasmon, Composite, Colloid
This article summarizes research activities of Hiroshi Sugimoto at the Photonics Center in Boston
University under the sponsorship of Premium Program of Graduate School of Engineering, Kobe
University (September 2014 July 2015). The main results are published in ACS Photonics (Vol. 2, pp.
12981305 (2015), DOI: 10.1021/acsphotonics.5b00233) and are reproduced in this article with
permission from ACS publications.
Colloidal silicon quantum dots (Si-QDs) have attracted research attention as nanoprobes for bio-imaging due to the prominent photoluminescence (PL) properties and biocompatibility. In this work, for the enhancement of photoluminescence efficiency of Si-QDs, we develop colloidal nanocomposites consisting of luminescent Si-QDs and gold (Au) nanorods by a facile synthesis process. We systematically investigate the structural and PL properties, and demonstrate significant enhancement of the spontaneous emission rate due to the surface plasmon resonance of Au nanorods. We also show that the emission from Si-QDs coupled to Au nanorods is highly polarized along the major axis of nanorods. The experimental results in combination with simulations of dipolar emission in the vicinity of Au nanorods indicate a ~3 times enhancement of the quantum efficiency. The Si-based active plasmonic-coupled nanocomposites developed in this work provide novel opportunities for biocompatible platforms that leverage nanoscale fluorescent probes for biosensing and bio-imaging device applications.