Heterovalent Zr4+/Nb5+‐Cosubstituted Negative Thermal Expansion Luminescent Materials with Anti‐Thermal Quenching Luminescence

Abstract Rare earth luminescent materials based on negative thermal expansion (NTE) have achieved thermally enhanced photoluminescence, but these materials typically exhibit relatively weak luminescence intensity at room temperature. In this work, adopting the cationic heterovalent substitution strategy, a series of Sc 2‐2x Zr x Nb x W 3‐1.5x O 12‐3x :Yb/Er (SZNWO x :Yb/Er) phosphors are prepared by solid‐state reaction. With the increase of x value, the substitution of Sc 3+ by Zr 4+ /Nb 5+ leads to a decrease in the local symmetry of Er 3+ . Compared with Sc 2 W 3 O 12 :Yb/Er (SWO:Yb/Er), this heterovalent substitution strategy significantly improves the luminescence intensity of SZNWO x :Yb/Er while retaining its anti‐thermal quenching luminescence and negative thermal expansion properties. By comparing and analyzing the temperature dependent temperature‐dependent steady‐state/transient spectra of SZNWO 0.10 :Yb/Er and SWO:Yb/Er phosphors, the anti‐thermal quenching mechanism is discussed from a new perspective. The luminescence intensity ratio (LIR) of the thermal coupled levels (TCL) of Er 3+ ( 2 H 11/2 / 4 S 3/2 ) is adopted for optical temperature sensing, achieving a maximum absolute sensitivity of 1.04% K −1 at 464 K and a maximum relative sensitivity of 1.08% K −1 at 298 K for the SZNWO 0.10 :Yb/Er phosphors. Finally, the potential applicability using the constructed flexible thin film to real‐world sensing scenarios is demonstrated, offering accurate and real‐time temperature monitoring at the local hotspot in the electronic component of the CPU chip.