Optimization of Visible Light Intensity from Upconversion Nanoparticles (UCNPs) under 980 nm Pump

Visible light is considered very promising for medical applications. Green light at 550 nm wavelength can be obtained using lanthanide-doped up-conversion nanoparticles (UCNPs) such as Erbium (Er). In this work, we analyzed optical characteristics and potentiality of Er to generate improved light at 550 nm utilizing the non-linear spectral mechanisms: up-conversion (UC) and excited state absorption (ESA) under 980 nm pump. To improve the intensity of 550 nm emission, co- doping with Ytterbium (Yb) has been investigated and found to be useful. We observed that adequate amount of Yb enhances visible emission intensity of Er through energy transfer process from Yb to Er under 980 nm pump, which can be used for improving visible emission in lifesaving medical applications.