Single-molecule laser nanospectroscopy with micro–electron volt energy resolution

Single-molecule nanospectroscopy Microscopic understanding and molecular-level control of individual electronic quantum states of a single molecule are a long-standing challenge in spectroscopy. Imada et al. found that a narrow-line tunable laser combined with a scanning tunneling microscope was able to generate photoluminescence spectra of the electronic and vibrational states of single molecules with micro–electron volt energy resolution and submolecular spatial resolution. The authors also discovered a way to tune the energy levels through a linear Stark effect and plasmon-exciton coupling in the tunneling junction. The proposed technique paves the way to efficient exploitation of energy conversion dynamics in electronic excited states, which constitutes the bedrock principle of such systems as LEDs, photovoltaics, and photosynthetic cells. Science , abg8790, this issue p. 95