Down-conversion near infrared emission in Pr3+, Yb3+ co-doped Y2O3 transparent ceramics

Pr3+, Yb3+ co-doped Y2O3 transparent ceramics have been prepared by the solid state reaction and vacuum sintering. Down-conversion near infrared emission has been demonstrated upon a 482 nm excitation. The energy of the 482 nm blue photon was first absorbed by Pr3+ and then delivered to Yb3+. Possible energy transfer mechanisms from Pr3+ to Yb3+ have been discussed. Under the 482 nm excitation, the Pr4+–Yb2+ charge transfer state would not seriously influence the energy transfer process. The dominant one should be either the cooperative down-conversion or the two-step photon emission. The efficient down-conversion near infrared emission has potential application in enhancing the conversion efficiency of crystalline silicon solar cells.