Rational Design of Molecular Cavity Polariton Relaxation

Maximizing the coherence between the constituents of molecular materials remains a crucial goal towards the implementation of these systems into everyday optoelectronic technologies operating at room temperature. In this study we experimentally assess the ability of strong light-matter coupling in the collective limit to reduce the impact of energetic disorder on polariton relaxation using multiple porphyrin-based chromophores in different Fabry-Perot (FP) micro-resonator structures. Following characterization of cavity polaritons formed from spatially separated porphyrin monomers and uniformly dispersed porphyrin dimers, we find the peak corresponding to the lower polariton (LP) state in each sample does not possess a width consistent with con- ventional theories of the dispersive energetics in these systems. We model the anomalous, dispersive behavior of the LP peak width in each sample effectively using the results of a Greens function theory used to explain motional narrowing of polariton luminescence spectra in high quality, fully inorganic micro-cavities. We correlate differences in the suppression of excitonic energetic disorder between our samples with macroscopic aspects of specific FP micro-resonators and microscopic attributes of the distinct porphyrin species we use to form cavity polaritons. Our results demonstrate how researchers can design coherence into hybrid molecular material systems to improve their suitability for next generation optoelectronic technologies.