ARTICLE pubs.acs.org/JPCC
Synthesis and Optical Characterization of Thermosensitive, Luminescent Gold Nanodots Jana Bomm,*,† Christina G€unter,‡ and Joachim Stumpe§ †
Department of Chemistry, and ‡Institute of Earth and Environmental Science, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam-Golm, Germany § Fraunhofer Institute for Applied Polymer Research (IAP), Geiselbergstrasse 69, 14476 Potsdam-Golm, Germany ABSTRACT: A facile one-pot synthesis for preparing thermosensitive, luminescent gold nanodots with diameters of 1 2 nm is presented. The influence of the alkyl chain length of the surface ligands (alkyl thiols) on the optical properties of the gold nanodots was investigated. The synthesized gold nanodots show strong thermosensitive photoluminescence. A photoluminescence quantum yield of 16.6% was observed at room temperature, which could be improved to a value of 28.6% when cooling the gold nanodot solutions to 7 °C. The synthesized thermosensitive, luminescent gold nanodots are interesting candidates for optoelectronic devices, medical imaging, sensing, or security labels.
’ INTRODUCTION Metallic nanoparticles have been studied widely due to their strong absorption in the visible range. This is caused by a coherent oscillation of conduction band electrons induced by an electromagnetic field, so-called surface plasmon resonance (SPR).1 3 It has been found that the SPR strongly depends on the size, the shape, and the chemical nature of the nanoparticles (NPs).3,4 The SPR band for spherical gold NPs is located at ∼520 nm, whereas very small NPs (
