Effect of initial pH on nanophosphor β-Ga2O3:Eu3+ prepared through sol–gel process

The red-emitting nanophosphor (β-Ga2O3:Eu3+) is synthesized by varying the initial pH of solution in sol–gel process. Above pH 7 the final product shows the single phase of β-Ga2O3:Eu3+. By increasing the initial pH, more hydroxyl ions (OH) are observed in the final product, and the particle size increases. This behavior originates from the interconnected polymer chain of hydroxyl ions. By increasing the initial pH, the red emission intensity of β-Ga2O3:Eu3+ decreases. This can be explained in terms of the following mechanism; at high pH, more hydroxyl ions act as a luminescent killer leading to the decrease in the emission intensity.