Conventional synthetic dyes exhibit a wide color spectrum but often release toxic and non-biodegradable chemicals, contributing to environmental harm [1]. Plasmonic nanostructures, particularly gold nanoparticles, offer a sustainable alternative due to their size-dependent optical properties, but gold thin films generally exhibit a limited color range due to morphological constraints [2]. This study aims to overcome the inherent limitations of gold thin films and expand the range of achievable plasmonic colors by introducing a titanium (Ti) adhesion layer beneath the gold film, modified by laser-induced thermal heating processing. This method aims to improve both the diversity of plasmonic colors and the adhesion properties of the film [3] and to provide environmentally friendly and durable alternatives for anti-counterfeiting [4], high-resolution printing, photonic devices, and decorative applications [5].
Gold nanoparticles were generated on glass substrates with Ti underlayers using a nanosecond pulsed laser operating at a 532 nm wavelength. A systematic investigation was carried out by varying the pulse energy (3.5-38.5 µJ), scan speed (1-500 mm/s), repetition rate (0.5-100 kHz), and hatch spacing (25-75 μm) to optimize the laser parameters for plasmonic color formation. The Ti underlayer was found to significantly influence the morphology of the gold film, promoting the formation of smaller islands during laser-induced dewetting. This morphological change broadened the achievable color range, including hues beyond the limited palette of gold thin films. The results demonstrated improved adhesion and enhanced color diversity. Introducing a Ti adhesion layer with laser thermal processing offers a scalable and cost-effective method for producing tunable, high-resolution plasmonic colors. 