Color tunable up-conversion emission of ZrO2:Yb3+, Er3+ thin films prepared by chemical solution deposition

The color-tunable up-conversion (UC) emission was observed in ZrO2:Yb3+, Er3+ thin films synthesized on fused silica substrates using a chemical solution deposition method. The crystal structure, surface morphology image and optical transmittance of ZrO2:Yb3+, Er3+ thin films were detected in the matter of Yb3+/Er3+ doping content. Under excitation by 980 nm infrared light, intense UC emission can be obtained from ZrO2:Yb3+, Er3+ thin films. Photoluminescence study shows that there are two emission bands centered at 548 nm and 660 nm in the UC luminescence spectra, which can be owing to (H-2(11/2), S-4(3/2))-> I-4(15/2) and F-4(9/2)-> I-4(15/2) transitions of Er3+ ions, respectively. In addition, the color coordinate of UC emission between green-red can be tuned by properly adjusting the dopant concentration, because the composition of Yb3+/Er3+ affect the red/green ratio via the process of cross relaxation and energy back transfer. Our study suggests that ZrO2:Yb3+, Er3+ thin films can be considered as promising materials for new photoluminescence devices.