Jihui Lang

Defects driven photoluminescence property of Sm-doped ZnO porous nanosheets via a hydrothermal approach

Samarium doped ZnO porous nanosheets were prepared via a hydrothermal approach and well characterized by X-ray diffraction (XRD), Raman spectroscopy, transition electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and UV–vis absorption spectroscopy. With increasing the Sm3+ doping concentrations, the crystallization of the thin nanosheets with irregular porosities became worse and the size of the porosities in the nanosheets gradually diminished due to the obstructions of Zn–O–Sm and the generated volatile gas. It was also found that the Sm3+ ions not only acted as the donors sinks to modulate the defects in host, but also expanded the visible light response of the ZnO. The slight redshift of UV NBE (near-band edge) emission as compared to undoped one indicated the band gap of the doped nanosheets became narrower due to the combination of the formed impurity band and the strong exchange interactions between electrons. The kinds of the defects as the deep-level-defect luminescent centers in DLE (deep-level emission) varied with the Sm3+ doping concentrations, and the detail change of the defects was also discussed in detail. These findings would be useful for the material design and defect modification for optical applications.