Real space visualization of entangled excitonic states in charged molecular assemblies

TL;DR

This study uses advanced microscopy techniques to visualize and control entangled excitonic states in charged molecular assemblies, providing insights into their photophysics and potential for quantum computing applications.

Contribution

It introduces a novel real-space imaging approach combining spectromicroscopy and atomic force microscopy to analyze entangled excitonic states in molecular assemblies.

Findings

Identification of a second low-lying excited state in anion monomers.

Demonstration of charge state control over excitonic coupling.

Visualization of delocalized single-exciton states at the nanoscale.

Abstract

Entanglement of excitons holds great promise for the future of quantum computing, which would use individual molecular dyes as building blocks of their circuitry. Even though entangled excitonic eigenstates emerging in coupled molecular assemblies can be detected by far-field spectroscopies, access to the individual modes in real space will bring the much needed insight into the photophysics of these fascinating quantum phenomena. Here we combine tip-enhanced spectromicroscopy with atomic force microscopy to inspect delocalized single-exciton states of charged molecular assemblies engineered from individual perylenetetracarboxylic dianhydride molecules. Hyperspectral mapping of the eigenstates and comparison with calculated many-body optical transitions reveals a second low-lying excited state of the anion monomers and its role in the exciton entanglement within the assemblies. We also demonstrate control over the coupling by switching the assembly charge states. Our results reveal the possibility of tailoring excitonic properties of organic dye aggregates for advanced functionalities and establish the methodology to address them individually at the nanoscale.