Upconversion white-light emitting of Tm3+ and Er3+ codoped oxyfluoride and its achieving mechanism

Tm3+ and Er3+ codoped oxyfluoride samples were synthesized by high temperature solid-state reaction. Intense upconversion white light of Tm3+ and Er3+ codoped oxyfluoride was observed under the excitation of a 980-nm infrared laser diode, which was composed of three primary colors, i.e., blue (from Tm3+), green (from Er3+), and red emissions (from Tm3+ and Er3+). The optimal white upconversion light, which is close to the standard achromatic point, was achieved firstly by phase transition from PbO to PbO2. The scanning electron microscopy, X-ray diffraction and Commission Internationale d’Eclairage chromaticity analysis revealed the dependence of the white upconversion light both on microstructure and Er3+ content. The sample with white upconversion light close to the standard achromatic point has potential applications in the fields of the three-dimensional solid-state display and multicolor backlight.