Organic Monolithic Natural Hyperbolic Material

Materials with hyperbolic dispersion are the key to a variety of photonic applications involving nanoimaging, hyper-lensing, and spontaneous emission engineering, due to the availability of high k modes. Here we demonstrate that spin-coated polycrystalline organic semiconducting films with a layered molecular packing structure can exhibit a hyperbolic dispersion over a wide spectral range and support the presence of surface excitonic polaritons. This was evidenced from 670 to 920 nm and is related to the negative real part of the dielectric permittivity of the selected quinoidal organic semiconductor. In addition, the accessible high k modes lead to changes in the spontaneous emission decay rate and photoluminescence quantum yield of emitters placed nearby the organic monolithic (composed of only one molecule and not necessitating an alternating multilayer structure) natural hyperbolic material. This study opens a new route toward single-step solution manufacturing of large-area, low-cost, and flexible organic photonic metadevices with hyperbolic dispersion.