Energy and electron transfer from frameworks of nanoporous
or mesostructured
materials to guest species in the nanochannels have been attracting
much attention because of their increasing availability for the design
and construction of solid photofunctional systems, such as luminescent
materials, photovoltaic devices, and photocatalysts. In the present
study, energy and electron-transfer behavior of dye-doped periodic
mesostructured organosilica films with different host–guest
arrangements were systematically examined. Fluorescent tetraphenylpyrene
(TPPy)–silica mesostructured films were used as a host donor.
The location of guest perylene bisimide (PBI) dye molecules, acting
as an acceptor, could be controlled on the basis of the molecular
design of the PBI substituent groups. PBI dyes with bulky substituents
and polar anchoring groups were located at the pore surface with low
self-aggregation, which induced efficient energy or electron transfer
because of the close host–guest arrangement. However, PBI dye
with bulky and hydrophobic substituents was located in the center
of template surfactant micelles; the fluorescence emission from the
host TPPy groups was hardly quenched when the host–guest distance
was longer than the critical Förster radius (ca. 4.5 nm). The
relationship between the energy or electron-transfer efficiency and
the location of guest species in the channels of mesostructured organosilica
was first revealed by molecular design of the PBI substituents.