Electron beam exposure- structural immunity and color tuning in Al2O3–ZrO2:Dy3+ binary matrix prepared by a hybrid approach

Abstract

This work report site selective emission of Dy3+ in ZrO2–Al2O3 binary system. Exposing these phosphors to electron beam irradiation tuned the emission color from blue to white, however crystalline and structural properties revealed by PXRD and TEM indicates the samples are immune to electron beam exposure. These phosphors were prepared by a hybrid approach, i.e. by combining solution combustion method and solid-state method. Nano particles of ZrO2 and Al2O3 were prepared by solution combustion method and then they were used as starting materials for solid state method. XRD analysis revealed presence of cubic-ZrO2 and α-Al2O3 phases in the prepared binary system. PL excitation spectra contained four peaks with maximum absorption intensity centered at 350 nm due to 6H15/2→6P7/2 transmission of Dy3+ ions. The emission spectra of phosphors excited at 350 nm show three characteristics peaks of Dy3+ centered at 485 nm (4F9/2→6H15/2), 580 nm (4F9/2→6H13/2) and 675 nm (4F9/2→ 6H11/2). Structural and photoluminescence properties were studied again, after exposing those phosphors to high energy electron beam. PL emission spectra were used to probe the hitherto unidentified changes. The asymmetry ratio (Ir) was analyzed in detail to study the fine information on the effect of electron exposure left unnoticed in XRD and TEM. Also, the Commission Internationale d'Eclairage color-coordinates revealed color tuning of the phosphors from blue to white, upon electron beam irradiation. This work reports Photoluminescence emission spectra as a probe to study the ultra-fine effects of electron beam irradiation in the materials.