Eco-friendly thermolytic synthesis and characterization of anacardic acid-capped cadmium sulfide nanoparticles using a single-source precursor

In recent years, there has been growing interest in environmentally friendly methods for synthesizing semiconductor nanoparticles using naturally derived bio-based capping agents instead of conventional toxic solvents and reagents. In this study, an eco-friendly route for synthesizing cadmium sulfide nanoparticles is presented using bis(piperidinedithiocarbamato)cadmium(II) as a single-source precursor and anacardic acid, a bio-derived capping agent isolated from cashew nut shell liquid. The precursor complex was thermally decomposed in hot anacardic acid at temperatures of 140 °C, 160 °C and 180 °C. The reaction produced anacardic acid-capped cadmium sulfide nanoparticles with varying optical and structural properties depending on synthesis temperature. UV-Vis absorption spectra revealed blue-shifted excitonic peaks indicative of quantum confinement, while photoluminescence analysis revealed typical emission features associated with cadmium sulfide nanocrystals. Transmission electron microscopy analysis revealed a morphology evolution from quasi-spherical to irregular cuboidal particles with increasing temperature. X-ray diffraction patterns indicated a temperature-dependent phase transition from cubic to hexagonal crystal structures. This green synthesis approach demonstrates that naturally derived anacardic acid can effectively stabilize and tune cadmium sulfide nanocrystals, offering a sustainable alternative for nanoparticle synthesis with potential applications in optoelectronic devices and photocatalysis.