A Zero‐Thermal Quenching Flexible Fiber for Visible Cellular Concentration Detection

Abstract The development of stable and precise visible light sources is crucial for advanced cellular analysis, yet current spectrophotometric systems face significant challenges, particularly temperature‐dependent signal drift and decreased measurement accuracy. In this work, a novel yellow‐emitting phosphor Gd 3 ScGa 4 O 12 : Dy 3+ is developed, which demonstrates exceptional thermal stability with zero‐thermal quenching (ZTQ) up to 200 °C. This remarkable performance is achieved through the strategic manipulation of trap‐assisted thermoluminescence enhancement mechanisms. In addition, a flexible optical detector is developed for oxyhemoglobin (HbO 2 ) concentration testing by incorporating Gd 3 ScGa 4 O 12 : Dy 3+ in stretchable elastomer‐based optical fiber. The fabricated device exhibits exceptional photoluminescence stability (near‐zero chromaticity drift, Δx/y < 0.003 from 10 to 40 °C), and promising measurement accuracy (200 µg mL −1 ). Tb 3+ / Eu 3+ / Pr 3+ doped Gd 3 ScGa 4 O 12 is also developed, which all perform favorable thermal stability. This finding not only provides a reliable and reusable cellular concentration detector but also establishes a ZTQ design framework for lanthanide‐doped materials.