Dy 3 + - and Eu3+-doped LaGaO3 nanocrystalline phosphors for field emission displays

Nanocyrstalline LaGaO3 and Dy3+- and Eu3+-doped LaGaO3 were prepared through a Pechini-type sol-gel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence, cathodoluminescence spectra, and lifetimes were utilized to characterize the samples. XRD reveals that the samples begin to crystallize at 900°C and pure LaGaO3 phase can be obtained at 1000°C. FE-SEM images indicate that the Dy3+- and Eu3+-doped LaGaO3 samples are both composed of aggregated spherical particles with sizes ranging from 40to80nm. Under the excitation of ultraviolet light and low voltage electron beams (1–5kV), the undoped LaGaO3 sample shows a strong blue emission peaking at 433nm, and the Dy3+- and Eu3+-doped LaGaO3 samples show their characteristic emissions of Dy3+ (F9∕24-H15∕26 and F9∕24-H13∕26 transitions) and Eu3+ (D0,1,25-F1,2,3,47 transitions), respectively. The relevant luminescence mechanisms are discussed.