Recent Progress in Universal Dyes
The unique structure and properties of each dye class allow dyes of that class to dye only those fibers with which they have affinity. Satisfactory dyeing results can only be obtained when this mutual affinity exists. Therefore, it would be of immediate practical significance if there was a universal dye, one dye that could be applied to different types of fibers. There are two possible means to achieve this: the modification of fibers and modification of dyes. This study reviews the design and synthesis of new dyes, called Universal Dyes, that would provide the features required for affinity to different fibers without the need to conduct separate chemical reactions outside the dye bath. Thus, these dyes can be applied to fibers of any type in the same dyebath. The principles and key problems in designing the molecular structure of Universal Dyes are also discussed.
We characterize upconversion (UC) photoluminescence (PL) in semiconductor quantum dot/rod/emitter nanostructures using one- and two-color cw excitation. We engineer improvements in UC quantum efficiency to 3% of the PL emission efficiency.