  We investigate adsorption effects of copper phthalocyanine molecules on
excitons and trions in air-suspended carbon nanotubes. Using photoluminescence
excitation spectroscopy, we observe that exciton energy redshifts gradually
with the molecular deposition thickness. The trion emission is also observed at
large deposition amounts, which indicates charge transfer between the
phthalocyanine molecules and carbon nanotubes. Analysis of the spectra for
individual tubes reveal a correlation between the exciton-trion energy
separation and the exciton emission energy, showing that the many-body
interaction energies scale similarly with the molecular dielectric screening.
