Intense Up-conversion Luminescence Of Rare-earth Doped ZrO₂ Powders Excited By 980nm

As the development of society, the improvement of scientific technology, and the widening of application, rare-earth doped materials which could emit luminescence have been used widely in the fields of display, lighting, and information industry and so on. China has the richest resource of rare-earth, so the rare-earth doped luminescent materials play an important role in the national research on luminescent materials and laser materials. The research on rare-earth doped luminescent materials comes to a new and active period, as series of high technology developed. The phenomenon of up-conversion is the peculiar property of rare earth ions. High efficient laser could be obtained by up-converting, so a most important task is to improve the efficiency of up-conversion.According to the J-O theory, the efficiency of up-conversion is seriously dependent on host materials. Usually, fluorides are attractive host materials as the efficiency of up-conversion is quite high due to their low phonon energies. One of the most successful systems of fluorides as rare earth doped host materials is the ZBLAN glass which has been used widely. Compared to fluorides oxides have attractive properties, such as high chemical stability and ease of fabrication and so on. Therefore, efforts to search for rare-earth ions doped oxide materials with high up-conversion efficiency are still attracting attentions. The up-converting properties of rare earth co-doped oxide powders which include ZrO2 and another oxide was investigated in this paper.In chapter one, we reviewed the developing history of research on up-conversion, displayed several types of up-converting models and introduced the situation of the research in this field at our institute. In chapter two, firstly, the J-O theory which plays an important role in the research on up-conversion was introduced. Then we showed the usual process and method of our research. And at last, we drew conclusions that show useful and actable methods to improve the efficiency of up-conversion. Chapter three showed the up-converting properties of Er3+/Yb3+ co-doped CaO-Al2O3-SiO2 powders excited under 980nm laser. And the differences of up-converting properties between oxides and fluorides were concluded by analyzing the up-converting properties of Er3+/Yb3+ co-doped CaO-Al2O3-SiO2 powders.In chapter four, the up-converting properties of Er3+/Yb3+ co-doped ZrO2-Al2O3 powders were reported. Intense red luminescence and weaker green luminescence were obtained under the excitation of 980nm. The main up-converting mechanisms of red and green luminescence were discussed, and the numbers of photons absorbed to produce such up-converting emissions were established. We detect the micro structure of samples, and find it beneficial for improve the efficiency of up-converting by making Al2O3 dissolved in ZrO2. Up-converting luminescence of Ho3+/Yb3+ co-doped ZrO2-ZnO powders was reported in chapter five. The spectrum of up-converting luminescence excited by 980nm laser shows three main emission bands.