Structural Color Generation on Transparent and Flexible Substrates by Nanosecond Laser Induced Periodic Surface Structures

Abstract

Laser patterning to fabricate micro/nanoscale structures attracts enormous attention as they find many functional applications owing to their controllable structure and unique properties. The present work proposes a unique solution-based method to fabricate laser-induced periodic surface structure (LIPSS) patterns on a thin film of Titanium (IV) butoxide and Ag organometallic (OM) solution-coated glass substrates with near infra-red (NIR) nanosecond (ns) laser. The formation of periodic patterns has been confirmed, the thin film solution concentration affects the LIPSS pattern thickness and a continuous pattern is achieved with the diluted solution. Parametric studies demonstrate that the LIPSS patterns could be achieved with optimal solution dilution, laser fluence, scan speed, and pulse duration. A high power and faster scan speed result in discontinued, and defective patterns. The photothermal process such as material reorganization followed by electromagnetic absorption that takes place during laser patterning is mainly responsible for the fabrication of controlled structures. LIPSS patterned surfaces exhibit iridescent surface coloration while illuminated with white light, and the color spectrum from red to blue is distinguished. LIPSS patterned substrates serve as mold and structures are transferrable to the poly dimethyl siloxane (PDMS) film and exhibit iridescent structural coloration like LIPSS patterned substrates.