Holographic photopolymerization for fabrication of electrically switchable inorganic-organic hybrid photonic structures

Holography offers a versatile, rapid and volume scalable approach for making large area, multi-dimensional, organic PBGs; however, the small refractive index contrast of organics prevents formation of a complete band-gap. The introduction of inorganic nanoparticles to the structure provides a possible solution. In contrast to the multiple steps (exposure, development and infiltration) necessitated by lithographic-based holography (e.g. photoresists), holographic photopolymerization of monomer-nanoparticle suspensions enables one-step fabrication of multidimensional organic-inorganic photonic band gap (PBG) structures with high refractive index contrast. The PBGs are formed by segregation of semiconductor nanocrystals during polymerization of the polymer network. Addition of CdSe/ZnS polymerization of the highly cross-linked polymer network. Addition of CdSe/ZnS quantum dots or ZnO nanocrystals to the H-PDLCs formulation results in phase segregation of the nanoparticles into the liquid crystal rich lamellae, producing photonic structures with high diffraction efficiencies that may be modulated by application of an external electric field.