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Room-Temperature Optical Picocavities below 1 nm3 Accessing Single-Atom Geometries

Research output: Contribution to journalLetter

Cloudy Carnegie, Jack Griffiths, Bart De Nijs, Charlie Readman, Rohit Chikkaraddy, William M. Deacon, Yao Zhang, István Szabó, Edina Rosta, Javier Aizpurua, Jeremy J. Baumberg

Original languageEnglish
Pages (from-to)7146-7151
Number of pages6
JournalJournal of physical chemistry letters
Issue number24
Publication statusPublished - 20 Dec 2018

King's Authors


Reproducible confinement of light on the nanoscale is essential for the ability to observe and control chemical reactions at the single-molecule level. Here we reliably form millions of identical nanocavities and show that the light can be further focused down to the subnanometer scale via the creation of picocavities, single-adatom protrusions with angstrom-level resolution. For the first time, we stabilize and analyze these cavities at room temperatures through high-speed surface-enhanced Raman spectroscopy on specifically selected molecular components, collecting and analyzing more than 2 million spectra. Data obtained on these picocavities allows us to deduce structural information on the nanoscale, showing that thiol binding to gold destabilizes the metal surface to optical irradiation. Nitrile moieties are found to stabilize picocavities by 10-fold against their disappearance, typically surviving for >1 s. Such constructs demonstrate the accessibility of single-molecule chemistry under ambient conditions.

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