Revealing carbon mediated luminescence centers with enhanced lifetime in porous alumina

TLDR: In this article, carbon ion implantation mediated blue photoluminescence (PL) and the corresponding bluish white phosphorescence of anodic aluminum oxide (AAO) are presented.

Abstract: Carbon ion implantation mediated blue photoluminescence (PL) and the corresponding bluish white phosphorescence of anodic aluminum oxide (AAO) are presented. In particular, the observed 465 nm luminescence is found to be more sensitive to carbon, while its lifetime is raised to its maximum from 6.7 to 10.4 μs at a fluence of 1 × 1016 ions/cm2. The observed phenomenon seems to be associated with the formation of oxygen vacancy (V0) via carbon ion enhanced modification of local AlO6 octahedral symmetry, as revealed from X-ray absorption spectroscopy at O-K edge, and also consistent with X-ray photoelectron spectroscopy (XPS). Detailed XPS analysis indicates the preference of carbon at the Al sites, rather than at O for both octahedral and tetrahedral structures, and form CAl cationic impurity, consistent with our density functional theory calculation. Further, carbon ion implantation driven enhanced PL lifetime is shown to be associated with energy transfer between V0 and the vicinal CAl. This work shows the potential of carbon doped AAO as a future candidate for developing rare earth free nontoxic phosphor.