Mn⁴⁺,Mg²⁺,Ga³⁺ Co-Doped Aluminate Phosphor And Its Application To Plant Growth-Promoting

Nowadays,with the improvement of people's living standard,people's demand for healthy life and green environment is increasing day by day,but the traditional way of increasing yield through pesticides and chemical fertilizers cannot meet these demands,so the way of enhancing plant growth efficiency through fluorescent conversion materials has been proposed and widely researched and discussed.It is well known that light is crucial for plant growth.Generally,three regions from the solar spectrum are irradiated light for plant growth,namely blue light(400-500 nm),red light(620-690 nm),which are responsible for phototropism and photosynthesis,respectively.Among them,photosynthesis determines the flowering and fruit ripening of plants,so the light in the red region(620nm-690nm)is the most important for plant growth,however,the intensity of the red part of sunlight is very low,resulting in low absorption efficiency of plants in this wavelength band,red fluorescent conversion materials with excellent performance are needed to compensate for itAluminate,as a material with low cost,simple and non-toxic preparation process,good stability and its multiple cationic lattice sites,is a potential substrate for probing fluorescent materials.Mn⁴⁺is a good activator ion due to its characteristic red emission and perfect coverage of the photosynthetic window of plant growth.Its emission is attributed to the energy level jump of ~2E(t₃~2)?~4A2(t₃~2)(620?750 nm)and excitation is attributed to ~4A₂?~4T₁(?350 nm)and ~4A₂?~4T₂(?455 nm),which can be well excited by UV and blue light.The research content and results of this thesis are as follows.Part ?:Mn⁴⁺,Mg²⁺,Ga³⁺-doped Sr₄Al₁₄O₂₅ was prepared by high-temperature solid-phase method,and the luminescence intensity of Sr₄Al₁₄O₂₅:Mn⁴⁺was enhanced by the doping of Mg²⁺and Ga³⁺relative to Sr₄Al₁₄O₂₅:Mn⁴⁺,has high conversion efficiency(EQE=31.6%)and the related properties were characterized and analyzed,and the possible luminescence mechanism leading to the enhanced luminescence was proposed.The effect of Ga³⁺and Mg²⁺substitution on the matrix lattice was investigated by spherical differential electron microscopy,and the deep mechanism of cation substitution on the luminescence enhancement was investigated by XANES.Part ?:The prepared Sr₄Al₁₄O₂₅:0.01Mn⁴⁺,0.01Mg²⁺,0.1Ga³⁺phosphors were prepared with PDMS glue to form a new photoconversion agricultural film.The results of experiments on tomatoes and Chlorella showed that the photoconvertible film had a catalytic effect on the early ripening and increased yield of tomato fruits,and also on the growth of Chlorella OD by about 25%.