Control of resonant wavelength from organic light-emitting materials by use of a Fabry-Perot microcavity structure

Abstract

We report the fabrication of Fabry–Perot microcavity structures with the organic light-emitting material tris- 8-hydroxyquinoline aluminum Alq3 and derive their optical properties by measuring their photoluminescence PL and absorption. Silver and a TiO2–SiO2 multilayer were used as metal and dielectric reflectors, respectively, in a Fabry–Perot microcavity structure. Three types of microcavity were prepared: type A consisted of air Ag Alq3 Ag glass ; type B, of air dielectric Alq3 dielectric glass ; and type C, of air Ag Alq3 dielectric glass . A bare Alq3 film of air Alq3 glass had its PL peak near 514 nm, and its full width at half-maximum FWHM was 80 nm. The broad FWHM of a bare Alq3 film was reduced to 15–27.5, 7–10.5, and 16–16.6 nm for microcavity types A, B, and C, respectively. Also, we could control the PL peak of the microcavity structure by changing the spacer thickness, the amount of phase change on reflection, and the angle of incidence.