The low-temperature photoluminescence of AgBr nanocrystals (NC's) in glass
has been examined. The wavelength of the indirect exciton emission and tran
smission electron micrographs indicate that various samples were fabricated
with nanocrystal radii ranging from 3 to 20 nm. Optically detected magneti
c resonance spectra for the larger NC's exhibit the normal donor, acceptor,
and intermediate case exciton resonances. Optically detected magnetic reso
nance spectra of the small NC's displayed only a single resonance at the av
erage of the bulk intermediate case exciton values. This collapse is attrib
uted to a confined wave function of the donor, which has a larger exchange
interaction with the acceptor increasing the singlet triplet splitting.