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

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 NO₂ 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.