Upconversion Photoluminescence in the Rare Earth Doped Y2O3 Phosphor Materials

In this chapter, the upconversion photoluminescence has been described in the rare earth doped Y₂O₃ phosphor materials. The upconversion (UC) is one of the interesting processes in the rare earth ions in which one can realize the emission of high energy Ultra-Violet (UV) and visible (Vis) photons with the help of low energy near infrared (NIR) photons. In this process, the Yb³⁺ ion transfers its energy cooperatively to some of the rare earth ions i.e. Er³⁺, Ho³⁺, Pr³⁺, Tm³⁺, Tb³⁺, etc. The absorption cross section of Yb³⁺ ion lies deeply in the region of NIR wavelength. This energy transfer occurs due to different processes, such as Ground State Absorption (GSA), Excited State Absorption (ESA), Energy Transfer Upconversion (ETU), Cooperative Energy Transfer (CET), etc. The UC photoluminescence in the Er³⁺, Ho³⁺, Pr³⁺, Tm³⁺ doped Y₂O₃ phosphor materials has been discussed in the presence of Yb³⁺ ion. This chapter also describes that the presence of Yb³⁺ ion in the rare earth doped phosphor materials enhances the emission intensity significantly due to energy transfer. The Yb³⁺ ion acts as sensitizer in the case of upconversion phosphors. The phosphor materials prepared by solution combustion method were also included. The application of rare earth doped Y₂O₃ phosphor materials has also been discussed.