Designing light emission with multiple organic based microcavities

A light emitting structure consisting of three coupled microcavities has been realized and studied. All three cavities contain a luminescent organic thin film of tetrakis(4-methoxyphenyl)porphyrin and they are coupled by means of two same LiF/ZnS Distributed Bragg Reflector. The entire structure is enclosed between a bottom and a top Bragg mirror with different layer number. Reflectivity spectra collected at different growing steps allow us to demonstrate the effective strong coupling between the three bare cavity modes. The reflectivity spectrum of thewhole structure shows the presence of threewell defined cavity dips. At normal incidence, the device emits three,well separated, peaks each one corresponding to a delocalized opticalmode of the coupled system,while at higher angles the peaks result blue shift. The experimental reflectivity spectra are in good agreement with a theoretical model based on the transfer matrix method. The model is applicable to any device, therefore, once the materials to employ as emitters are established, the cavity can be designed in order to amplify just the modes that correspond to the peak wavelengths of the emission spectrum and/or to change completely the spectral shape