Near-field observation of luminescence of silicon phthalocyanine dye aggregates at low temperature

We have investigated the morphology and the luminescence of silicon phthalocyanine dye aggregates using a low-temperature scanning near-field microscope. We have observed the luminescence spectrum depending on the position in an aggregate at 77 K. The behavior is originated from the energy transfer process among radiative states and nonradiative centers in microscopic domains.