Rational Screening and Design of Highly Efficient Mn ²⁺ ‐Based Inorganic Phosphors: Zn ₂ GeO ₄ :Mn ²⁺ Scintillator for High‐Quality X‐Ray Imaging With Thermo‐Responsive Performance

Thermo‐responsive Mn 2+ ‐based inorganic phosphors have been explored as promising scintillators for temperature sensing and imaging under X‐ray irradiation. However, its development is usually limited by opportunism and trial‐and‐error methods. In this paper, rational screening was employed to select scintillator materials with thermo‐responsive performance. Zn 2 GeO 4 was successfully mined by considering three critical parameters (effective atomic number, bandgap, and internal quantum efficiency ( IQE )). Among pre‐selected inorganic hosts, Zn 2 GeO 4 :Mn 2+ phosphor possesses high IQE (84.7%) and extraordinary XEL intensity (864% of that of Bi 4 Ge 3 O 12 powders). The optimal sample exhibits a perfect linear response to X‐ray. Its space resolution achieves 25 lp/mm in air and underwater. Besides, the optimal sample presents high relative sensitivity ( S R ) for temperature sensing. For photoluminescence, the highest S R values based on fluorescence intensity ( FI ) mode and excitation intensity ratio mode reach 5.49 %K −1 and 6.38 %K −1 , respectively. Under X‐ray irradiation, the highest S R value based on FI ‐mode reaches 5.24 %K −1 . The above results prove that the rational screening method is a reliable and efficient method to select scintillator materials based on three critical parameters, and demonstrate that Zn 2 GeO 4 :Mn 2+ inorganic phosphor possesses the potential as an efficient thermo‐responsive scintillator.