Single-molecule study for a graphene-based nano-position sensor

G Mazzamuto,G Navickaite,A Tabani,F Koppens,F S Cataliotti,L Gaudreau,K Schädler,C Toninelli,S Rizvi,S Pazzagli,A Reserbat-Plantey

doi:10.1088/1367-2630/16/11/113007

Abstract

In this study we lay the groundwork for a graphene-based fundamental ruler at the nanoscale. It relies on the efficient energy-transfer mechanism between single quantum emitters and low-doped graphene monolayers. Our experiments, conducted with dibenzoterrylene (DBT) molecules, allow going beyond ensemble analysis due to the emitter photo-stability and brightness. A quantitative characterization of the fluorescence decayrate modification is presented and compared to a simple model, showing agreement with the dependence, a genuine manifestation of a dipole interacting with a 2D material. With DBT molecules, we can estimate a potential uncertainty in position measurements as low as 5 nm in the range below 30 nm.

Highlights

We show a fluorescence image of a DBT:anthracene sample deposited on silica, similar in characteristics to the one measured by atomic force microscopy (AFM)
To our knowledge, the highest ever measured transfer efficiency from single emitters to graphene, amounting to (61 ± 21)%
We can detect a fluorescence resonant energy transfer (FRET)-like effect to distances well beyond the characteristic 10 nm of standard acceptor–donor energy transfer

Summary

Introduction: single emitters close to interfaces

A single atom or molecule in the vicinity of a planar layered medium represents a paradigmatic system in near field physics [1]. Experiments performed by Drexhage in 1970 [5] already showed a clear modification of emitter decay rate and radiation pattern as a function of the distance to a reflecting interface. This is understood as a feedback effect of the reflected complex field on the molecule itself. The radiative decay rate results modified, as well as the efficiency of all those processes which can be described by the exchange of virtual photons This is the case of what happens in a fundamental process in nature such as photosynthesis, relying on the energy transfer between different chromophores. In this paper we provide a first proof of principle for a graphene nanoruler, based on the measurement of the energy-transfer rate between single organic molecules and a graphene monolayer

Nanoscopic rulers by optical means

Dibenzoterrylene single emitters

Graphene monolayer

Lifetime measurements

Findings

Conclusions