Abstract
Hybrid phosphors have gained large interest in the field of biomedical systems owing to their excellent physicochemical features. The potentiality of hybrid phosphors also lies in gathering favourable features of varied nanoforms in a single construct. An advantage of polymer as one of the components as host material for luminescent phosphors is their simple method of preparation, superior mechanical properties, higher flexibility and lighter density. The polymer films are prepared by melt casting or spin coating and materials of any desirable size or shape can be prepared from polymers. Moreover, manufacturing of polymers is cheaper and the energy consumption of making polymers is much lower. Different types of optically transparent polymers can easily be incorporated with phosphors. In a hybrid matrix it has higher thermal stability and luminescence output. Besides, being an agent for in-vivo imaging, hybrid phosphor based fluorescent materials also demonstrate several advantages for use in bioassay and therapy. Amongst different phosphor-based nanomaterials, upconversion phosphors are potential optical contrast agents for uses in biomedical appliance due to their long emission lifetime, sharp emission peaks, and their photostability. In this chapter, a comprehensive overview on hybrid upconversion phosphor is discussed with the basic conceptions that include the mechanisms for the illustration of different fluorescent behaviours, the different methods applied for the preparation of these phosphors, and finally the uses of these materials in biological arena. In addition, new trends in these type of materials are summarized with future perspectives.