Tunable deep-level emission in ZnO nanoparticles via yttrium doping

Research highlights: → Photoluminescent properties of Zn1-xYxO nanoparticles depend on the Y-doping concentration. → With increasing Y-doping concentration, the UV emission intensity can be strongly enhanced. → With increasing Y-doping concentration, the peak position with maximum intensity in deep-level emission band can be gradually tuned from 539 nm to 598 nm since the Y doping has redistributed the defects in the Zn1-xYxO nanoparticles. - Abstract: Yttrium-doped ZnO nanoparticles (Zn1-xYxO, x = 0, 0.03, 0.05) were synthesized by sol-gel technique. The effects of yttrium doping concentration on the structures, morphologies and optical properties of as-synthesized Zn1-xYxO nanoparticles were investigated in detail. The results from structural characterizations clearly demonstrated that yttrium ions were successfully doped into the crystal lattice of ZnO matrix. Besides a UV emission centered at ∼383 nm, the PL spectra of all the samples exhibited a broad deep-level emission, which can be deconvoluted into two Gauss peaks centered at 539 nm (P1) and 598 nm (P2), respectively. As the concentration of Y doping increased from 0% to 5%, the peak position with maximum intensity in deep-level emission band was gradually tuned from 539 nm to 598 nm and the relative intensity ratio of IP1/IP2 also decreased step by step, which revealed a unique optical property of yttrium-doped ZnO nanoparticles.