Structural Reconfiguration Unlocks Pressure‐Ultrasensitive and Efficient Above‐Bandgap Emission in (AMP)PbI 4 Perovskite for Optical Manometry

ABSTRACT Optical pressure measurement technique provides convenience and high‐precision capability to remote pressure probing, which holds broad application potential in fields such as high‐pressure physics, novel material synthesis, and micro/nanoelectronics. Nevertheless, under relatively low‐pressure conditions (below ≈ 5 GPa), highly sensitive pressure sensors are required due to the low sensitivity, and pressure‐induced quenching effects in various optical manometry. To address these limitations, we reported an ultrasensitive, excitonic luminescent optical sensor based on Dion–Jacobson (D–J) phase perovskite (AMP)PbI 4 (AMP = 4‐(aminomethyl)piperidine). Upon compression, (AMP)PbI 4 exhibits an above‐bandgap emission with the intensity enhancement of approximately 300% at 0.97 GPa and a pronounced redshift, resulting in an exceptional sensitivity of d λ /d p = 24.283 nm/GPa. Combining synchrotron diffraction and Density Functional Theory (DFT) calculations, we attributed the ultrasensitivity of the above‐bandgap emission to the intrinsically soft lattice. The pressure‐induced enhancement in luminescence, on the other hand, is associated with local Pb─I bond reconfiguration and optimized [PbI 6 ] octahedral connectivity, which facilitate radiative recombination in the low‐pressure regime. These results not only underscored the significant potential of structure reconfiguration tuning of the above‐bandgap emission for high‐performance optical pressure sensing materials, but also offered valuable insights into the underlying mechanism governing high‐pressure luminescence.