Nano-scale photoexcited exciton mapping: Visualizing molecular orbitals via single molecule's photocurrent

Photoexcited carriers in semiconductors or molecules can be measured in photocurrent devices as optoelectronic. Incorporationg optical devices with light sources into scanning probe microscopy makes it possible to achieve improved resolution of photocurrent imaging beyond typical microscopic measurements with the optical diffraction limit. Recently, Imai-Imada et al. successfully visualized photocurrent channels from the molecular orbitals of a single molecule at atomic resolution with scanning tunneling microscopy coupled with a narrow-line tunable light source.