Upconversion luminescence properties of Er(3+)-Bi3+ codoped CaSnO3 nanocrystals with perovskite structure

New phosphor nanocrystals of ASnO3:Er3+ (A = Ca, Sr, and Ba) and CaSnO3:Er(3+)-Bi3+ were prepared by a hydrothermal method. Their structures were examined by X-ray diffraction and Raman spectroscopy. Upconversion luminescence properties of the Er3+ ions in these host materials were investigated upon excitation at 980 nm. Green emission bands of Er3+ around 528 and 545 nm were more favorable in CaSnO3 than in SrSnO3 and BaSnO3. This was interpreted in terms of a crystal structural distortion and configuration coordinate model. The investigation of the upconversion luminescence of Er(3+)-Bi3+codoped CaSnO3 nanocrystals indicates that Bi3+ ions could largely sensitize the emission of Er3+ ions which was attributed to the efficient energy transfer from Bi3+ to Er3+ ions and the modification of the local symmetry of Er3+ ions. The results show that the CaSnO3:Er(3+)-Bi3+ nanocrystals have potential application for fabricating visible upconversion devices.