Assessment of the electronic structure, morphology, and photoluminescence properties of Ca9-xAl6O18:xEu3+ phosphor using the hydrothermal assisted solid state method

Cubic phase Ca9-xAl6O18:xEu3+ red phosphors have been successfully fabricated using the hydrothermal assisted solid state method. The atomic site occupation of the matrix, morphology, luminescent properties, quenching mechanisms, and thermal stabilities are investigated. The possible sites of Eu3+ in a matrix crystal lattice are investigated via formation energy using first principle calculations. Under 395 nm excitation, Ca9-xAl6O18:xEu3+ shows a red emission at 618 and orange emission at 594 nm and the optimal Eu3+ ion concentration is x = 0.06. The effect of the reaction solution composition on the morphology and emission spectra are investigated using SEM and photoluminescence (PL) spectrum measurements. The results reflect that the samples have different morphologies in different reaction solutions. Additionally, the PL intensities of Ca8.94Al6O18:0.06Eu3+ decreased to 80.6% as the temperature increased from room temperature to 150 °C. Ca9Al6O18:Eu3+ phosphors may potentially be used for white LEDs.