A Wavelength-Scale Silk Protein Color Filter Array for Ultra-High-Resolution 80k DPI Displays

Abstract

The manifestation of color is either obtained through intrinsic quantum mechanical properties of materials (absorption or fluorescence) or through structural materials at the scale corresponding to the wavelength of light. Particularly, structural colors can occur with ultrathin layers, and their properties are modulated by nano-structuring (photonic crystals and plasmonics), garnering much interest. However, the fabrication complexity and costs to miniaturize color devices and increase performance pose challenges. Here, a sub-mu m metal-insulator-metal color filter array (CFA) is reported based on the electron-beam lithography resist function of silk protein. High-resolution CFAs are implemented by depositing silver on grayscale patterned silk layers without complex and intricate nano-structuring. Precise control of the electron-beam dosage allows engineering of the desired color, and high quality-factors (Q-factors) lead to an extensive color gamut. Moreover, the light is well-confined even when the pixel size is reduced to 300 nm. Consequently, the famous painting The Starry Night is realized as an 80k dots per inch (DPI) resolution CF display. In addition, secured information through color noising is generated by incorporating the CFA. This study presents a new way to add multispectral depth to future research in bioimaging, biosensors, displays, and information security.