Growth of Er3+/Yb3+ co-doped CaMoO4 thin film by a spray coating and its upconverting luminescence.

Polycrystalline Er3+/Yb3+ co-doped CaMoO4 (CaMoO4:Er3+/Yb3+) film was successfully fabricated by a spray coating method. Crystal structure, surface morphology and upconversion (UC) luminescent properties were investigated. Under 980-nm excitation, CaMoO4:Er3+/Yb3+ film exhibited strong green UC emissions at 530 and 550 nm (2H,11/2 --> 4S3/2 - 4I15/2) visible to the naked eye with a weak red emission near 660 nm (4F9/2 --> 4I15/2) corresponding to the intra 4f transitions of Er3+. A possible UC mechanism related to the pump-power dependence is discussed in detail.