Turning Thermal Roll‐Off Into Thermal Boost in Perovskites via Heat‐Activated Interfacial Polarization

ABSTRACT For semiconductor devices operating under elevated temperatures, especially in high‐insolation regions, the intrinsic thermal degradation of optoelectronic performance poses a fundamental challenge. Herein, we report a heat‐activated interfacial polarization strategy that uniquely converts this performance loss into a substantial gain. By incorporating electron‐deficient N‐heteroaromatic cations into lead–iodide perovskites, we induce a thermally driven electron cloud deformation at the organic–inorganic interface. This process establishes a reversible interfacial dipole that reshapes the electrostatic landscape, lowering charge‐transport barriers and effectively screening deep trap states. As a result, carrier mobility increases by ∼100‐fold and trap density reduces by ∼80% upon heating from 300 to 363 K, directly inverting the conventional thermal‐roll‐off trend. The universality of this mechanism is demonstrated across 1D, 2D, and 3D perovskite systems, all exhibiting pronounced photocurrent enhancement with temperature. As a proof‐of‐concept application, fire‐warning detectors based on this strategy achieve 100‐fold and 1000‐fold enhanced responsivity to flame‐signal infrared irradiation and smoke‐marker NO 2 gas, respectively, under identical heating conditions. This work establishes thermal energy as a functional asset rather than a performance liability, opening new avenues for thermally robust and smart optoelectronics.