Short and long wavelength laser pulse-dependent physicochemical properties of plasmonic metal nanocomposites: A comparative assessment

Abstract

Repeated studies revealed that various nanostructures with tailored physicochemical properties are highly desirable for biomedical and engineering applications. Hence, this study investigates the systematic synthesis and characterizations of gold/copper nanocomposites (Au-CuNCs) prepared via the pulsed laser ablation in liquid (PLAL) approach. In this process, solid Au and Cu targets were ablated in deionized water (DIW) using a nanosecond pulsed laser at two different wavelengths (1064 nm and 532 nm). The primary objective is to evaluate the impact of laser wavelength variation on the structural, optical, and morphological properties of the resulting NCs. All NCs were analysed to evaluate the effect of varying wavelengths on their fluorescence, absorbance, morphology, and structure. TEM, HRTEM, and STEM images confirmed the nucleation of Au-CuNCs with the corresponding mean diameters of 7.88 ± 3.97 and 6.39 ± 4.07 nm of 1064 and 532 nm, respectively. ATR-IR and XRD analysis affirmed the high purity and strong nanocrystallinity of all specimens, respectively. EDX maps and spectra of the obtained NCs disclosed the distributions and compositions of constituent chemical elements. The lifetime decay analyses of the NCs exhibited an appreciably low fluorescence lifetime of 2.83 µs and 2.74 µs of the donor, ascribed to radiative energy transfer and photon emission. Optical band gap energy of the NCs made at 1064 nm 532 nm corresponded to 3.90 eV and 4.03 eV. It is established that via the change of the ablating laser wavelength, the physical characteristics of these NCs can be tailored, contributing to sustainable growth with diverse applications.