Surface defect modification of ZnO quantum dots based on rare earth acetylacetonate and their impacts on optical performance

Graphical abstract: RE(AcAc)₃ (RE = Ce, Dy and Tb) can realize the defects modification of ZnO QDs based on the linkage occurs between the protons of the hydroxyl groups on the surface of ZnO QDs and the π–system of acetylacetone. The color coordinate could be shifted among yellow-green, blue-green, and green region by changing the RE (AcAc)₃ ratios. The stable Ce(AcAc)₃/ZnO QDs with average sizes of about 3.0 nm can be obtained. The calculated band gap data also proved the efficient modification of Ce(AcAc)₃ for ZnO QDs with the largest variation of band gap energy of 0.039 eV (from 3.583 eV to 3.544 eV). - Highlights: • Defects modification of ZnO QDs based on rare earth acetylacetonate. • Stable Ce(AcAc)₃/ZnO QDs with an average sizes of about 3.0 nm. • The color coordinate could be shifted among yellow-green, blue-green, and green region by changing the RE (AcAc)₃ ratios. - Abstract: The surface defect modification has an important effect on the application of ZnO quantum dots, and it has gained much progress in recently years, propelled by the development of additives. Our research efforts are directed toward developing a new surface modification additive RE(AcAc)₃ (RE = Ce, Dy, Tb) to achieve fine ZnO QDs and adjust their surface properties. RE(AcAc)₃/ZnO QDs nanostructured materials have been designed and prepared, and particular emphasis has been given to the relation between the surface modification and optical properties. The effects of RE(III) acetylacetonate modification on the FT-IR, TEM images and photoluminescence (PL) spectra were investigated, and the surface defect modification principle and effect were discussed in details. The band gap (E_g) was also calculated to prove the surface modification effect. For the RE(AcAc)₃/ZnO QDs complex materials, stable linkage occurs because of the affinity of −COOH from acetylacetonate anionic ligand to zinc oxide surfaces, with attachment to the zinc oxide by hydrogen bonding between the protons of the hydroxyl groups on the surface of ZnO QDs and the π–system of acetylacetone.