Semiconductor Bowtie Nanoantenna from Coupled Colloidal Quantum Dot Molecules

Abstract

Top-down fabricated nanoantenna architectures of both metallic and dielectric materials demonstrated powerful functionalities for Raman and fluorescence enhancement with relevance to single molecule sensing, while inducing directionality of chromophore emission with implications for single photon sources. Herein, we synthesize the smallest bowtie nanoantenna by selective tip-to-tip fusion of two tetrahedral colloidal quantum dots (CQDs) forming a dimer. While the tetrahedral monomers emit non-polarized light, the bowtie architecture manifests nanoantenna functionality of enhanced emission polarization along the bowtie axis as predicted theoretically and revealed by single particle spectroscopy. Theory also predicts the formation of an electric-field hotspot at the bowtie epicenter. This is utilized for selective light induced photocatalytic metal growth at that location, unlike growth on the free tips in dark conditions thus demonstrating the bowtie dimer functionality as a photochemical reaction center. Our findings pave a path for additional bottom-up bowtie architectures applicable in optics, sensing and photocatalysis.

9 pages, 5 figures

References in corpus (1)

• Electronic coupling in colloidal quantum dot molecules; The case of CdSe/CdS core/shell homodimers

Cited by in corpus (5)

• Neck Barrier Engineering in Quantum Dot Dimer Molecules via Intra-Particle Ripening
• Two Biexciton Types Coexisting in Coupled Quantum Dot Molecules
• Photon Correlations in Colloidal Quantum Dot Molecules Controlled by the Neck Barrier
• Twisting enabled charge transfer excitons in epitaxially fused quantum dot molecules
• Coupled oscillators model for hybridized optical phonon modes in contacting nanosized particles and quantum dot molecules