Visible-to-ultraviolet Upconvertion: Energy transfer, material matrix, and synthesis strategies

Abstract

In recent years, Upconversion (UC) material has attracted much attention because of its fantastic energy transfer capability of converting the low-energy photons into high-energy photons via anti-Stokes process. Among UC materials, the visible-to-UV UC materials exhibit remarkable potential in laser conversion, photo-catalysis, the sterilization as well as antibiosis in biological areas because of their capability of converting the visible radiation into ultraviolet emission. Considering the interesting UC process and large potential application of the visible-to-UV UC materials, it is necessary to overview its intrinsic UC mechanism, material structure, as well as material synthesis techniques for the development of UC material. This work focus on the visible-to-UV UC materials and review its current research situation, the challenges in its research field, as well as analyzing and comparing recent investigations to provide valuable evaluation for such materials both from theoretical and commercial perspective. The most effective UC matrix and luminescent centers in recent works were summarized and the intrinsic mechanisms of visible-to-UV UC were introduced. The material design strategies and techniques for the synthesis of visible-to-UV UC phosphors were focused. The advantages and the limitations of visible-to-UV UC material are discussed in detail, and a reasonable expectation for the emerging trends of such potential material is provided.