1-dimensional photonic crystal is an alternately-stacked nanostructure which consists of two different materials with different refractive index which results in performing structural color. Compared to chemical color, structural color becomes more pronounced under stronger ambient light. One of the example of struc-tural color made by 1-D photonic crystal is shiny blue color of Morpho butterfly, being promising for reflec-tive displays.
In this thesis, I develop new type of active color pigments to provide enhanced optical property and simple process of fabrication. Color pigments are composed of alternated dielectric layers deposited on one part of hemisphere of magneto-responsive spherical microparticle. In color pigment, dielectric layers provide structural color with high color purity and magnetic balls provide magnetic response and rotation under ex-ternal magnetic field, thereby enabling switching of structural color. Highly monodisperse droplets of photo-curable resin is generated in a dripping mode with glass capillary device, which are then collected in petri-dish. Two methods are used to make ball magneto-responsive. Firstly, magnetic nanoparticles dispersed in photo-curable resin is used in oil phase, followed by emulsification. After making magnetic nanoparticle magnetic-oriented in emulsion, UV light is exposed to make magnetic ball. Secondly, iron layer is deposited on spherical ball. Dielectric layers of $SiO_2$ and $TiO_2$ are deposited alternately after magnetic ball is fabricated in order to deposit 1-D photonic crystal on spherical ball. Prior to dielectric layer deposition, chromic layer is deposited on the magnetic ball in order to prevent back reflection of the transmitted light and increase color purity. Then, $TiO_2$ and $SiO_2$ layers are alternately deposited to form 1-D photonic crystal-based color reflector. The color can be controlled by changing the thickness of deposited layers of $TiO_2$ and $SiO_2$. As the active color pigments are free to rotate under external magnetic field and able to perform the structural color on and off, these can function as color pigments in ‘Gyricon Display’. We believe that the active structural color pigments can potentially serve as reflective display such as E-ink.