Polariton emission from polysilane-based organic microcavities

We report the observation of strong coupling between exciton and photon modes in a conjugated polymer-based semiconductor microcavity. Thin films of the σ-conjugated poly[bis(p-butylphenyl)silane] (PBPS) were inserted between metal and dielectric mirrors to form the microcavity structures. Variation of the PBPS film thickness between 80 and 140 nm allowed the cavity photon resonance to be tuned in the vicinity of the free exciton energy. The expected anticrossing behavior, with intensity and linewidth averaging, was observed at room temperature in the cavity reflection spectra and the vacuum Rabi splitting was found to be $⩽430 meV.$ This large value is consistent with the expectations of transfer matrix reflectivity calculations performed with optical constants data derived from a Kramers–Kronig analysis of the PBPS absorption spectrum. Angle-dependent photoluminescence measurements were performed for the microcavity with a 120 nm thickness PBPS layer. Unlike the emission from a standard, weakly coupled, cavity, the polariton emission shows almost no blueshift with angle, a desirable feature for potential display applications.