Exploration of the Preparative, Luminescent Characteristics, and Cellular Harmful Impact of Cerium-Enriched Cadmium Sulfide Nanoparticles

Objectives: The synthesis of pure and Cerium Doped CdS with the composition Cd1-xCexS (where x = 0.001, 0.002, 0.003, and 0.004 %) was conducted to investigate the physical, structural, and optical properties of Ce-doped CdS. Method: Cerium-doped cadmium sulfide nanoparticles (Ce:CdS NPs) are synthesized using co-precipitation methods to control size, morphology, and optical properties. The band gap of these semiconductor nanoparticles was optimized through Diffuse Reflectance Spectroscopy (DRS). Crystallite size, microstrain, lattice parameter, and volume were characterized via X-ray diffraction (XRD). Emission properties were analyzed using photoluminescence spectroscopy (PL). Surface morphology and particle size were examined with Field Emission Scanning Electron Microscopy (FESEM). The surface functional groups were studied using Fourier Transform Infrared Spectroscopy (FTIR), while the chemical composition was evaluated through energy dispersive X-ray analysis (EDAX). The anticancer efficacy of Ce-doped nanoparticles was assessed with the MTT assay on a breast cancer cell line. Findings: In DRS spectra, higher dopant concentration leads to a reduced band gap, known as a red shift, suggesting new localized energy levels from Ce3+ ions in the CdS lattice. Increased cerium ion concentration results in an impurity band overlapping with the conduction or valence band edge of CdS. EDAX spectra show notable peaks like Cd-L, S-K, and Ce-K, confirming the presence of both pristine and doped nanoparticles. PL spectra indicate strong emission peaks in the visible region. FESEM analysis reveals cerium-doped nanoparticles typically have an irregular spherical distribution due to high surface energy. XRD studies indicate a phase transition from cubic to hexagonal structure at an optimal 4% cerium doping. The presence of larger cerium ions notably affects particle size, lattice parameter, strain, and volume. FTIR spectroscopy identifies functional groups and capping agents in cetyl trimethylammonium bromide-assisted cerium-doped CdS nanoparticles. The spectrum displays characteristic peaks of CTAB alongside those of the inorganic core. Additionally, cerium-doped CdS nanoparticles demonstrate dose-dependent cytotoxicity, with increased concentrations decreasing cell viability, typically due to reactive oxygen species leading to oxidative stress and DNA damage. Novelty: Typically, cubic CdS nanoparticles demonstrate significant cytotoxic effects; however, it is noteworthy that for the first time, thermodynamically more stable hexagonal cerium-doped CdS nanoparticles exhibit superior anticancer activity in comparison to the standard therapeutic agent, doxorubicin. Keywords: Red Shift, Cytotoxic effect, Hexagonal Ce doped CdS, Reactive oxygen species, MTT assay