Luminescence tuning of upconversion nanocrystals

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Upconversion luminescence allows materials to emit higher energy photons upon excitation with lower energy photons.
• Beta-NaYF(4) nanorods are a promising host material for upconversion applications.
• Lanthanide ion doping is crucial for tuning upconversion luminescence properties.

Purpose of the Study:

• To tune the upconversion luminescence of beta-NaYF(4) nanorods by tridoping with lanthanide (Ln3+) ions.
• To investigate the effects of cerium (Ce3+) doping on NaYF(4):Yb3+/Ho3+ nanorods.
• To study Gadolinium (Gd3+) doping effects on NaYF(4):Yb3+/Tm3+(Er3+) nanorods for multicolor emission and magnetic properties.

Main Methods:

• Tridoping of beta-NaYF(4) nanorods with specific lanthanide ions (Ce3+, Gd3+, Yb3+, Ho3+, Tm3+, Er3+).
• Characterization of upconversion luminescence spectra under 980 nm excitation.
• Analysis of luminescence intensity changes with varying dopant concentrations and pump power density.
• Investigation of magnetic properties of Gd3+-doped nanorods.

Main Results:

• Ce3+ doping in NaYF(4):Yb3+/Ho3+ nanorods induced unusual Ho3+ transitions and altered emission intensity ratios due to energy transfer.
• Luminescence dominance shifted between Ho3+ transitions in Ce3+-tridoped samples with increasing pump power.
• Gd3+-tridoped NaYF(4):Yb3+/Tm3+(Er3+) nanorods exhibited multicolor emission from UV to NIR.
• Gd3+ doping introduced characteristic UV emission lines and paramagnetic/superparamagnetic behavior.

Conclusions:

• Tridoping beta-NaYF(4) nanorods with specific Ln3+ ions offers effective control over upconversion luminescence.
• Ce3+ and Gd3+ ions can be utilized to achieve tunable multicolor emission and introduce magnetic functionalities in upconversion nanostructures.
• The findings provide insights into energy transfer mechanisms and pave the way for novel optical and magnetic nanomaterials.