Large-scale controlled bio-inspired fabrication of 3D CeO2:Eu3+ hierarchical structures for evaluation of highly sensitive visualization of latent fingerprints

Abstract

Novel CeO2:Eu3+ (1-9 mol %) nanophosphors (NPs) with flower-like hierarchical structures and controlled shape and size were effectively synthesized by hydrothermal method using Epigallocatechin gallate (EGCG) as bio-surfactant. Optimized NPs was explored as an effective labeling agent for visualization of latent fingerprints (LFPs) on different porous and non-porous surfaces. Visualized fingerprints (FPs) revealed first, second and third-level ridge particulars with high contrast, high selectivity and low background interference. X-ray photoelectron spectral studies (XPS) evident that the presence of oxygen vacancies responsible for the surface modification of these superstructures. The induced oxygen vacancies were also strongly influenced the photoluminescence (PL) properties of the prepared samples. 3D flower-like hierarchical architectures were explored by tuning different experimental parameters. Growth mechanism of 3D architectures developed through two dimensional (2D) flakes involves nucleation, growth, Ostwald ripening and recrystallization. The photometric properties evident that, the prepared samples exhibit intense red color with color purity ~ 80 %. Investigation on visible light photocatalytic degradation of methylene blue (MB) has been examined using these powders. Results discussed were noteworthy for exploring these phosphor materials in multi-functional applications such as optoelectronics, forensic and photocatalysis applications.