Elsa Aulia, Latifatul Aisyah Nabila, Siti Azimatul Luthfiyyah, Arif Hidayat, Ahmad Taufiq, Hazri Bakhtiar, Muhammad Safwan Abd Aziz, Nurul Hidayat
Refractive index (RI)-based sensing has led to significant advancements in optical sensor applications. Via this fundamental detection mechanism, reliable chemical, biological, and environmental monitoring can be achieved. Herein, we reported for the first time the potential of an RI sensor based on the colorimetric mechanism using gold/ Arcangelisia flava ( L. ) Merr (Au/AF nanohybrids). The main objective was to investigate how laser ablation time (10-30 min) influenced the Au/AF nanohybrids’ plasmonic, morphological, structural, and RI sensing characteristics. The ultraviolet–visible spectroscopy (UV-Vis) characterization suggested that the ablation time altered the plasmonic properties of the nanohybrids. Meanwhile, the morphological analysis using scanning electron microscopy (SEM) indicated the formation of spherical structured Au/AF nanohybrids. X-ray diffraction (XRD) patterns also confirmed the formation of a cubic structure of Au nanoparticles and some extra peaks corresponding to the presence of AF minerals. Furthermore, the addition of ethylene glycol with increased RI values into the Au/AF nanocolloidal solutions exhibited linear correlation with the absorbance intensity of their respective UV-Vis spectra. Therefore, the Au/AF nanohybrids were sensitive to RI change. The highest RI sensitivity and linearity, with values of 122.98 a.u./RIU and 0.915 respectively, were exhibited by 10-min ablated Au/AF sample. Remarkably, our study suggested that the ablation time tended to decrease the sensing sensitivity. These findings highlighted the critical role of ablation time in tuning plasmonic behavior and established Au/AF nanohybrids prepared by PLAL as a promising platform for colorimetric RI sensing. © 2026 The Authors.
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia; Laser Center, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor, Skudai, 81310, Malaysia; Center of Science and Engineering, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia
