Multifunctional Mo 4+ ‐Doped Cs 2 HfCl 6 Double Perovskites Enabling Near‐Infrared Lighting and Pressure‐Responsive Optical Manometry

ABSTRACT Mo 4+ ‐doped Cs 2 HfCl 6 double perovskites were rationally designed as multifunctional near‐infrared (NIR) emitters to achieve high‐performance luminescence and pressure‐responsive optical functionalities. Upon ultraviolet light excitation, the studied samples exhibited intense NIR emission, with intensity strongly dependent on Mo 4+ content, and the observed concentration quenching resulted from electric dipole‐dipole interaction. Moreover, the synthesized compounds possessed high quantum efficiency and remarkable thermal stability. Leveraging the designed double perovskites, NIR light‐emitting diode was packaged to demonstrate their potential applications in night vision, noninvasive detection, and bioimaging. Furthermore, in situ Raman spectroscopy and x‐ray diffraction analyses verified the outstanding structural robustness of the synthesized compounds throughout the investigated pressure range. Upon lattice compression, an obvious spectral red‐shift was observed, enabling pressure‐modulated luminescence. Specially, with elevating the pressure from 0.13 to 14.06 GPa, the NIR emission band centroid changed from 907.1 to 939.4 nm, contributing to a high sensitivity of d λ /d p = 4.41 nm GPa −1 . Additionally, ratiometric analysis revealed a maximum relative sensitivity of 24.3% GPa −1 together with a thermally stable manometric factor of 363.2 K GPa −1 . These findings suggested that the Mo 4+ ‐doped Cs 2 HfCl 6 double perovskites, integrating efficient NIR luminescence with excellent pressure‐responsive characteristics, are promising candidates for functional lighting and advanced optical manometry.