A process for green synthesis of europium-doped cadmium sulfide (cds:eu) nanocrystalline thin films

Abstract

The present invention relates to a process for synthesizing europium-doped cadmium sulfide (CdS:Eu) nanocrystalline thin films. Europium-doped CdS nanocrystalline thin films are synthesized via green chemical bath deposition using Azadirachta indica leaf extract (10 g / 40 mL) as capping / reducing agent with cadmium acetate, thiourea, ammonia (pH 10), TEA, and Eu(NO₃)₃ (0.01-0.1 M) at 60°C / 60 min on glass substrates. XRD confirms hexagonal wurtzite structure with lattice expansion; UV-Vis shows band gap redshift (3.3 to 2.2 eV); PL reveals Eu³⁺ emissions (616-620 nm, optimal at 0.01 M). DFT (SIESTA, GGA-PBE) validates 4f gap states and stability (-3.53 eV / atom). This sustainable method tunes optical properties for photonic / optoelectronic devices.