Light absorption of the most plants is in range of blue (440 nm), deep-red (660 nm) and far-red around 700-740 nm. The deep-red and far-red light play important roles in reactions of photomorphogenesis of plants. Although red emission phosphors have been researched extensively for white light-emitting diodes, deep-red and far-red emission phosphors for plant growth have been reported inadequately. Thus, in this work, far-red emitting CaYAlO4:Mn4+ phosphor was synthesized by co-precipitation method coupled with various annealing temperature from 800 oC to 1300 oC for 5 h. The crystal structure, morphology, and photoluminescence properties of CaYAlO4:Mn4+ phosphors were investigated in detail. The crystallinity of the phosphor belongs to tetragonal system with space group I4/mmm. Y3+ and Ca2+ ions are coordinated by nine oxygen atoms to form [YO9] and [CaO9] polyhedrons, and the Al3+ ions are coordinated by six oxygen atoms forming [AlO6] octahedrons that provided suitable sites for Mn4+ ions. The obtained sample showed an irregular surface morphology with micro size particles. | Far-red emission of CaYAlO4: Mn4+ synthesized by co-precipitation method
