Persistent luminescence via up-conversion: Modulation of emission phenomena in multifunctional glass composites

• Grant number: 24/02102-0
• Support Opportunities: Regular Research Grants
• Duration: December 01, 2024 - November 30, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Convênio/Acordo: CNPq
• Principal Investigator: Danilo Manzani
• Grantee: Danilo Manzani
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 23/05994-6 - Energy conversion involving lanthanide ions in oxyfluoride glasses and glass-ceramics: From fundamentals to luminescence and thermometric properties, AP.R

Abstract

Materials that exhibit persistent luminescence (PersL) can be characterized by their ability to absorb light from an excitation source and slowly release it as luminescence over a long period of time. Classic examples of their application include emergency signaling. The discovery of new efficient, size modulated, and different emission regions, has enabled their use in various fields such as anti-counterfeiting luminescent markers, information storage, thermosensors, medical diagnostic bioimaging, etc. However, these materials are usually obtained in powder form, typically requiring incorporation into polymeric or glass matrices to expand their applications on a large scale. Recently, the study of incorporating these materials into glass matrices has shown advantages over more commonly used polymers, as they exhibit high thermal and chemical stability. In addition, luminescent materials operating via up-conversion have stood out due to their ability to convert lower-energy radiation, such as infrared, into higher-energy emission, such as in the visible and UV regions. Studies have demonstrated the possibility of combining materials operating via up-conversion and PersL, resulting in a material with the advantages of both phenomena. Creating a glass composite using lanthanide-doped glasses exhibiting up-conversion is advantageous, as persistent particles are incorporated and energy transfer is facilitated by the glass-particle interface. As non-radiative decay due to lattice vibrations in the matrix can suppress luminescence via up-conversion, making it essential to choose glass matrices with low phonon energy. In this context, the use of oxyfluoride glasses, such as the TeO2-Na2O-NaF-NaPO3 composition doped with Er3+/Yb3+ and/or Tm3+/Yb3+, is advantageous due to their low melting temperatures (600 - 850 °C), UV to near-IR transparency, and low phonon energy (700 - 800 cm-1). On the other hand, PersL materials should have low optically stimulated luminescence (OSL) emission; for instance, the excitation source of the luminescent glass should not influence the trap depopulation of PersL material. Gallate-based materials, such as ZGSO:Cr3+ (Zn1.33Ga1.335Sn0.33Cr0.005O4), are ideal because they exhibit low OSL and can be excited in the visible range (e.g., Er3+ emission at 543 nm). Thus, this project aims to develop glassy composites, exploiting the synergy between the up-conversion phenomena originating from the glassy matrix and the persistent luminescence of the incorporated particles. (AU)