Far-red-emitting Eu3+-activated Ca2SrWO6 double perovskite phosphors, crystallized in a monoclinic phase, were prepared using a high-temperature solid-state reaction. Thorough investigation included structural refinement, surface morphology insights, and detailed photoluminescence (PL) characterization. The materials, when exposed to n-UV light of 396 nm, emit standard Eu3+ emissions in the red (616 nm) and far-red (699 nm) spectral region, following 5D0-7Fj (j = 1-4) transitions of the activators. These emissions closely match the absorption window of plant phytochromes, demonstrating the suitability of Ca2SrWO6:Eu3+ as a far-red component for n-UV-pumped phosphor-converted LEDs in horticultural lighting. Emission in the far-red spectral region fulfils the requirements of plant photoreceptors, which then utilize it in photosynthesis. The optimal Eu3+ concentration is determined to be 3 mol%. The time resolved photoluminescence (TRPL) studies were incorporated to examine the PL decay characteristics of the phosphors under study. Additionally, insights into radiative properties were investigated using the Judd-Ofelt (J-O) theory. Determination of J-O intensity parameters, Ω2 and Ω4, of Eu3+ shows favourable radiative properties of the Ca2SrWO6:Eu3+ phosphors. Furthermore, the robustness of the PL emission at elevated temperatures was discovered via temperature-dependent photoluminescence (TDPL). The CIE color coordinates (0.646, 0.353), with a very high color purity of 92%, show a strong far-red emission response. Hence, the collective results reveal strong potential of the phosphor under study in phosphor-converted light-emitting diodes (pc-LEDs) for plant-growth lighting applications.
Degda et al. (Thu,) studied this question.