ZGSO:Cr³⁺,Ni²⁺ Persistent Phosphors with Dual Emission in NIR-I and SWIR Ranges for Bio-Imaging Applications

Persistent luminescence (PersL) is widely used for near infrared (NIR-I, 650-950 nm) imaging as they allow getting images without background. Bio-imaging in the second shortwave-infrared region SWIR-II (NIR-II, 1000-1400 nm) is less widespread but is growing as it offers the advantages of low photon scattering, increased in vivo penetration depth, and improved imaging clarity. In this work, the preparation and the complete optical properties of a new material is reported, Zn_1.33Ga_1.33Ni_0.005Cr_0.005Sn_0.33O_3.995 (ZGSO:Cr³⁺, Ni²⁺) able of emitting in both deep-red/NIR-I and SWIR (NIR-II) and shows its potential in bioimaging. ZGSO:Cr³⁺, Ni²⁺ can be excited using different sources such as X-rays, UV, and visible light to emit persistent signals in dual biological windows (dual-BW). By integrating an energy transfer process from Cr³⁺ to Ni²⁺ within this newly synthesized material, the influence of co-dopants on signal intensity and emission wavelengths is sought to explore. PersL at ≈700 nm (NIR-I) and ≈1300 nm (NIR-II) have been tested in preliminary bioimaging experiments using different protocols, allowing signal detection with good spatial resolution and depth sensitivity. The dual-BW PersL imaging strategy expands the toolbox for highly accurate analysis and has, for the first time, allowed access to accurately high-resolution sensing, and tracing.