Modulation On Upconversion Luminescence Of NaYF₄:Er³⁺,Yb³⁺ Nanoparticles In Fabry-perot Microcavity

Lanthanide-ions?Ln3+?-doped upconversion?UC?nanomaterials have attracted a lot of research interest,utilizing long-lived,ladder-like levels of Ln3+.Due to the nonlinear process,the upconversion luminescence?UCL?efficiency for currently available UC nanomaterials is usually low,the effect of improving luminescence efficiency is still relatively limited.Here,we intend to control the upconversion luminescence process through the optical resonant mode within the microcavity structure to improve luminescence efficiency and obtain pure color UCL.In this paper,the research contents are mainly carried out from the following two aspects:one is about preparing Fabry-Perot resonant cavity to control and improve luminescence efficiency,the other one is about fabricating F-P cavity with weakly scattering medium to investigate the optical transmission and resonance characteristics,as well as the effect on the luminescence.The main work is as follows:Firstly,the structure of 20nm NaYF4:Er³⁺,Yb3+ nanoparticles in the Fabry-Perot resonant cavity with inner MgF2medium is fabricated.By changing resonant position of the F-P microcavity,we explore the effect of resonant mode on the luminescence intensity and lifetime.The study shows that when the resonant position of the cavity is on the emission wavelength of Er³⁺,the corresponding UCL cal be enhanced obviously,and the high-contrast luminescence can be achieved by suppressing the other luminescence channels.Secondly,we replace the MgF2 homogeneous medium with SiO2 weakly scattering medium prepared by the sol-gel method in the Fabry-Perot cavity.By testing the reflectance spectrum,it is observed that the cavity with scattering medium is in a completely different situation compared to homogeneous medium:the resonant position which should be a valley in the reflection spectrum shows a peak.Furthermore,NaYF4 nanoparticles luminescence in this F-P cavity is investigated.