Investigation on the upconversion emission in 2D BiOBr:Yb3+/Ho3+ nanosheets

• Yb3+/Ho3+ co-doped BiOBr nanosheets were synthesized via hydrothermal method.
• Ho3+ ions exhibit unusual UC emission behavior in BiOBr nanosheets.
• A different UC mechanism for NIR emission of Ho3+ is proposed.
• Yb3+/Ho3+ co-doped BiOBr nanosheet can be a great candidate for green UC phosphors.

As lanthanide doped upconverting host, two dimensional (2D) nanostructure materials have remarkable advantages compare with the bulk materials, but excellent 2D upconversion nanohost is still few up to date. In this work, Yb3+/Ho3+ co-doped BiOBr nanosheets have been successfully prepared via a facile hydrothermal method, which were characterized by X-ray diffraction, transmission electron microscopy, Atomic Force Microscope, Raman spectra, Fourier transform infrared absorption and UC luminescence spectra. Under excitation at 980 nm, bright green UC emission centered at 550 nm accompanied with weak red (663 nm) and near infrared (NIR) UC emissions (760 nm) were observed. Power dependence studies revealed that NIR and red UC emissions were both dominated by a two and one-photon process due to saturation effects that is related to the special crystal structure of BiOBr nanosheets, and a different UC mechanism of NIR emission from Ho3+ was proposed accordingly.

UC spectra of BiOBr:1%Ho3+, 1%Yb3+ nanosheets under 980 nm LD excited.Figure optionsDownload as PowerPoint slide