In this work we show that a PTCDA molecule, which can be lifted from a surface and attached to the STM tip, emits light due to decay of the excited anionic state.

N. Friedrich, A. Rosławska, X. Arrieta, K. Kaiser, M. Romeo, E. Le Moal, F. Scheurer, J. Aizpurua, A. G. Borisov, T. Neuman, G. Schull
Fluorescence from a single-molecule probe directly attached to a plasmonic STM tip
Nature Communications, 15, 9733 (2024)