Multicolor Upconversion Luminescence from Single Materials

Upconversion (UC) luminescence (UCL) from single materials has garnered significant attention in recent years due to its potential applications in bioimaging, anti-counterfeiting, and display technologies. This review explores the most recent developments in achieving multicolor UCL using single materials. We provide a detailed discussion of the strategies used to obtain multicolor UCL from single materials, including structural design, modifications to excitation power density, control of excitation pulse width, changes in excitation wavelength, temperature adjustments, and the use of time-resolved techniques for dynamic UCL color tuning. The review examines the basic mechanisms behind parameter manipulation and their direct impact on the UC process, highlighting their adaptability for a broad spectrum of applications. Moreover, we examine current challenges and outline potential future directions for the progress of multicolor UCL based on single materials.