Synthesis and Infrared Multi-band Absorption Properties of Core-shell NaYF4:Yb3+, Er3+@SiO2 Nanoparticles

Due to the unique size effects, nanomaterials in infrared absorption have attracted much attention for their strong absorption in the infrared region. To achieve the infrared multi-band absorption, we propose to synthesize a core-shell structure nanomaterial consisting of NaYF 4 :Yb 3+ , Er 3+ core and a layer of SiO 2 as shell. A series of NaYF 4 :Yb 3+ , Er 3+ nanocrystals were synthesized through hydrothermal method by adjusting the ratio of citric acid(CA)-to-NaOH, and the effects of CA concentration, and NaOH concentration were studied in detail. NaYF 4 :Yb 3+ , Er 3+ @SiO 2 nanoparticles were synthesized by sol-gel method using TEOS as silica source. The results show that the core-shell NaYF 4 :Yb 3+ , Er 3+ @SiO 2 nanoparticles were successfully synthesized. Up-conversion spectra of these nanoparticles were recorded with 980 nm laser excitation under room temperature. There are no changes of the emission centers of nanoparticles before or after silica coating, but the emission intensities of nanoparticles after silica coating are weakened. Furthermore, the property of infrared multi-band absorption was tested through ultraviolet-visible-near infrared spectrophotometer and infrared absorption spectra. The results illustrate that the multi-band infrared absorption nanomaterial was successfully synthesized.