Development of deep red–emitting CaBiVO5:Pr3+ phosphor for multifunctional optoelectronic applications

Orthorhombic Pr³⁺-doped calcium bismuth vanadate (CBV: Pr³⁺) phosphors have been synthesized successfully via a citrate-gel method. The single-phase formation of CBV: Pr³⁺ phosphor has been endorsed by X-ray diffraction (XRD) analysis. The scanning electron microscopy (SEM) image reveals dense-particle packaging with the quasi-spherical shape for the prepared CBV: Pr³⁺ phosphors. Under blue light excitation, CBV: Pr³⁺ phosphors exhibit intense red emission bands located at 608 and 656 nm wavelengths, overlapping with the absorption spectrum of P_R phytochrome, which is present in plants. To achieve the maximum red intensity, the Pr³⁺ ion concentration is optimized to be 1.25 mol% in the CBV host, after which the emission intensity ceases due to concentration quenching. Dexter's theory disclosed the possibility of d-d multipolar interaction among Pr³⁺ ions at higher concentrations of Pr³⁺ ions in the CBV host. The CIE coordinates are found to be positioned in the pure red region for CBV: Pr³⁺ phosphor and in the proximity of red-emitting commercial phosphor. The temperature-dependent spectral studies manifest substantial thermal stability of the as-synthesized phosphor. All the studies mentioned above specify the tremendous potentiality of thermally stable CBV: Pr³⁺ phosphor in agricultural lighting and w-LED applications.