Laser‐Induced Rare Earth Up‐Conversion Luminescent Plastics

Rare earth elements‐doped glass‐ceramics have been widely studied in recent decades due to their excellent up‐conversion luminescence properties. However, the preparation method of glass‐ceramics limits its application, and it is difficult to realize up‐conversion luminescence by laser lithography in a glass medium. Therefore, it is necessary to find new materials to replace the up‐conversion glass‐ceramics to realize in situ up‐conversion luminescence. Here, up‐conversion nanocrystals (NaYF4) have been successfully in situ generated with different crystal phases in transparent plastics by using a femtosecond laser, and realize the precise tuning of the fluorescence intensity of up‐conversion luminescence. Furthermore, up‐conversion luminescence at different excitation wavelengths is realized by doping with rare earth elements such as Er, Tm, and Ho. The stability test shows that the laser‐generated up‐conversion nanocrystals inside the plastics can maintain stable up‐conversion luminescence in solvents and high temperatures. This breakthrough technology has led to the development of a variety of precisely controllable up‐conversion luminescent plastics, which provides a practical technical route for the application of new luminescent solid media.