A facile and efficient strategy for the preparation of stable CaMoO4 spherulites using ammonium molybdate as a molybdenum source and their excitation induced tunable luminescent properties for optical applications

Abstract

Stable CaMoO₄ spherulites were synthesized by a facile hydrothermal method using (NH₄)₆Mo₇O₂₄·4H₂O as a Mo source and these spherulites were formed according to the theoretical predictions of the crystal splitting theory. Rietveld refinement and photoluminescence studies confirmed that the CaMoO₄ spherulites are defect-free. The CaMoO₄ spherulites showed greenish-blue emission and the single emitting component of CaMoO₄:Eu³⁺ spherulites led to a novel excitation induced efficient emission property like organic light emitting diodes. Cathodoluminescent properties of the CaMoO₄:Eu³⁺ exhibited individual emissions from MoO₄²⁻ clusters and Eu³⁺ ions. The white color emissions were clearly explained using Gaussian fitting curves. The corresponding CIE chromaticity coordinates provided their emission potentiality in the green, red and white regions for optical and biological applications.