Luminescent spectra of organic thin films sandwiched with two mirrors
were measured in an effort to detect optical microcavity effects. Narr
owing and enhancement of photoluminescent spectra were observed from t
he tri- (8-hydroxyquinolinol) aluminum monolayer with the mirrors at b
oth sides. Furthermore, the narrowing of spectra was also observed fro
m electroluminescent devices fabricated with two mirrors.