Superstructures of doped yttrium aluminates for luminescent and advanced forensic investigations

Abstract

Nanocrystalline Tb3+ (1–11mol %) doped YAlO3 phosphors were prepared by biocompatible combustion route using Aloe Vera gel as a fuel. The average crystallite sizes were estimated using XRD and TEM found to be ∼27 nm. Scanning electron micrographs showed microlayered superstructures of various shapes of uniform particles. Upon 341 nm excitation, the photoemission profile of YAlO3: Tb3+ exhibit a narrow green emission peak at 545 nm due to 5D4→7F5 transition. Optical parameters such as Judd–Ofelt parameters, radiative transition probabilities, radiative lifetimes, branching ratio, stimulated emission cross-section and optical gain were estimated by Judd–Ofelt theory. CIE coordinate for the optimized phosphor was (x = 0.308, y = 0.435) which is very close to NTSC standard value for green emission. Further, the correlated color temperature was estimated and found to be ∼6178 K. A simple, fast, highly sensitive and ecofriendly method for the detection and enhancement of fingermarks in various forensic relevant materials was presented.