Phenomenology of Emission Color Tunability in Upconversion Nanoparticles

Abstract

Upconversion nanoparticles have gained significant attention for their potential in modern technology due to their ability to exhibit wide and continuous tuning of excitation and emission wavelengths. However, challenges such as low-energy photon absorption, dependence on bias for color variation, high manufacturing costs, and lack of long-term stability of emitters limit the potential of these materials. To overcome these obstacles and improve tuneability for technological applications, researchers have explored various methods of tuning the frequency upconversion process by altering the physical, chemical, and morphological properties of the upconversion material. This chapter delves into the different aspects of color tunability in upconversion nanoparticles, examining the conditions that lead to changes in color output and highlighting research in this field.