Orthorhombic Pr 3+ -doped calcium bismuth vanadate (CBV: Pr 3+ ) phosphors have been synthesized successfully via a citrate-gel method. The single-phase formation of CBV: Pr 3+ 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: Pr 3+ phosphors. Under blue light excitation, CBV: Pr 3+ 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 Pr 3+ 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 Pr 3+ ions at higher concentrations of Pr 3+ ions in the CBV host. The CIE coordinates are found to be positioned in the pure red region for CBV: Pr 3+ 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: Pr 3+ phosphor in agricultural lighting and w-LED applications.
K E Y W O R D Sagricultural lighting, citrate gel, energy transfer, phytochrome, vanadate | 5765 KAUR And JAYASIMHAdRI the capability of controlling spectral composition via phosphor coated over the LED chip. [7][8][9] The emission from pc-LED matching well with plant photoreceptors (P R and P FR ) can offer ideal production in plant growth systems. Besides this, pc-LED delivers numerous advantages over prevailing lighting sources (incandescent, metal halide, and high-pressure lamps) such as environmental protection, improved energy efficiency, smaller size, advanced control capabilities, longer service time, and reduced radiated heat. [10][11][12] In general, pc-LEDs fabricated by coupling with FR-emitting Mn 4+ -doped phosphors and other red phosphors may exhibit an emission overlapped with the absorption spectrum of phytochromes. Such fabricated pc-LEDs can aid to control the duration of sunlight sensed by plants, which can regulate the flowering time of plants. 2,5,[13][14][15] Therefore, it is of great significance to develop eco-friendly phosphors-emitting red light under n-UV/blue light excitation for promoting regulated plant growth.Recently, numerous red phosphors incorporating rareearth (RE) ions (Eu 3+ and Sm 3+ ) have been investigated, which possess excellent chemical, thermal, and physical stabilities along with intense emission corresponding to the intra-4f transitions. 12,[16][17][18] But, there are only a few reports on Pr 3+ -doped red-emitting materials and their application for artificial lighting in plant growth systems. Such red luminescent material can additionally be applied in various fields, such as solar cells, white (w)-LEDs, fingerprint sensing, biologica...