Near-infrared to visible upconversion emission was observed with 980 nm excitation and analyzed in Er-doped and Er/Cr-codoped KNbO3 phosphors. In both systems, exciton emission appeared at 555 nm under 405nm excitation. In the codoped phosphors, upconversion emissions in the green, red, and infrared region were observed from the 4S3/2 and 4F9/2 states of Er3+ ions and the 4T2 state of Cr3+ ions respectively. We explain the emissions by two-step absorption of Er ions and the energy transfer processes between Er ions, from Er to Cr ions, and from Cr to Er ions.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)