A Study on the Luminescence and Mechanism of Quantum-cutting Phosphate Phosphors by Using Synchrotron Radiation
本文中，我們利用同步輻射光源探討了Ba3Gd(PO4)3、Sr3Gd(PO4)3與Ca8MgGd(PO4)7等磷酸鹽量子剪裁螢光體；並且利用螢光放射與螢光激發光譜等量測實驗建立Tb3+- Tb3+及Gd3+- Tb3+的能量轉移機制與量子剪裁模型。|
Quantum cutting (QC) is a concept that the energy of a vacuum ultraviolet (VUV) photon is more than twice the energy of a visible photon, so that there is enough energy to emit more than one visible photon per each VUV photon absorbed. The application of VUV-excited phosphors are mainly focus on plasma display panels (PDP) and mercury-free lighting devices. Theorolly, it is possible to achive quantum efficiency (QE) as high as 200% through a QC process. To fulfill the requirement of QC, it is importment to choice the proper phosphor materials. According to several studies, rare earth ion-doped fluoride materials can be an outstanding canadle for developing the application of VUV-excited sources. However, the chemical properties of fluoride materials are unstable under atmosphere, in contrast, oxide have good chemical stability, and easily to be synthesized than fluorides. In a sense, oxide could be another choice suitable for quantum cutting effect. In this work, by using synchrotron radiation as a light source, we have investigated several phosphate quantum-cutting phosphors, such as Ba3Gd(PO4)3, Sr3Gd(PO4)3, Ca8MgGd(PO4)7. Based on the analysis of the experimental photoluminescence (PL), photoluminescence excitation(PLE), We have also proposed plausible mechanisms and energy level diagrams involving Tb3+- Tb3+or Gd3+- Tb3+energy transfer model to rationalize the observed QC process.