Understanding and controlling light-matter interactions is of central interest for various applications such as communication, renewable energy, and sensing technologies. Photonic crystals (PCs) are a class of materials that can manipulate propagation of electromagnetic waves to on-demand display different color, using at least two materials with distinct refractive indices. Briefly, the mechanism of reflection of light in 1-D photonic crystal is driven by following parameters: (1) layer thickness dictates the wavelength of the reflected light according to Bragg’s equation and (2) the difference between the refractive indices dictates the intensity of the reflected light. The goal of this RET project was to develop two suitable polymers (polystyrene and phenolic resin) and to design their appropriate thicknesses to fabricate a stack of bi-layer films for preparing a photonic crystal that would reflect light in a targeted wavelength range (visible, ~400-700 nm) with desired intensity. Specifically, the layer thickness can be controlled by varying the polymer solution concentrations for spin coating. Additionally, we identified a step of surface treatment is necessary for improving the wettability between distinct polymer layers. Through this project, we successfully developed a lesson for chemistry course that may be used for high school and junior-college students.[ZQ1] This lesson addresses the 5 Es of learning at this level (engage, explore, explain, elaborate and evaluate) where students demonstrate an understanding of the nature of properties of various types of chemical solutions, develop and use models to explain the dissolving process in solvents at the molecular level by spin-coating paints on various surfaces.

Rational designing of one-dimensional photonic crystal

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.