Structure, morphology and absorption characteristics of gold nanoparticles produced via PLAL method: Role of low energy X-ray dosage

Abstract This paper reports the effects of low energy X-ray irradiation doses on the structures, morphologies and absorbance of some colloidal gold nanoparticles (AuNPs) produced in distilled water via the one-step pulse laser ablation in liquid (PLAL) method. An Nd:YAG pulse laser (wavelength of 1064 nm and fluence ranges of 0.076–7.692 J/cm2) was used to ablate the gold plate surface (acted as a target) immersed in distilled water (10 mL). The laser pulse duration was adjusted to 2.5 min (1000 pulses), 5 min (2000 pulses). Simultaneously, the colloidal suspension was irradiated with low energy X-ray. The obtained samples were characterized thoroughly using different analytical instruments. High quality, pure, surfactant-free AuNPs with well-defined morphology and broad size distribution were achieved. The recorded values of the Zeta potential of the as-synthesized AuNPs were increased from -33.1 to -41.2 mV which was mainly due to the low energy X-ray dose-mediated photo- and Auger-electrons generation plus the fragmentation of the bigger NPs into highly stable tinier species inside the colloidal suspension. The observed blue-shift in the absorbance peaks of the NPs centered at 523, 529, and 526 nm irradiated with the corresponding fluences of 0.076, 3.846, and 7.692 J/cm2 was ascribed to the quantum size effects. It is established that the synergy between laser ablation and low energy X-ray does may be effective to prepare the contaminants-free AuNPs in the liquid suspension in a simple rapid and cost-effective way.