Precision Strain Engineering in Perovskite Optoelectronics via Shock‐Driven Gradient Annealing for Enhanced Stability and Light Response

High-performance perovskite-based optoelectronic devices require low defect density and efficient charge carrier extraction to achieve optimal performance. However, residual tensile strain in perovskite films can reduce defect formation energy, negatively impacting charge mobility and increasing non-radiative recombination. This study introduces laser shock-driven gradient annealing (SDGA), a novel approach to strain management and crystallization control in perovskite films. SDGA utilizes laser-induced plasma shocks to achieve gradient annealing, effectively releasing residual strain and enhancing structural uniformity. By processing in a semi-sealed environment, this method mitigates challenges such as rapid evaporation and inconsistent crystallization common in open-environment annealing, reducing lattice distortion and improving film quality. The plasma-induced pressure drives solute diffusion and grain fusion, modulating the energy band structure and enhancing the n-type semiconductor properties of perovskite. Precise control of laser intensity allows for fine-tuned crystallization, yielding highly efficient and stable perovskite structures. Devices treated with SDGA demonstrate a responsivity of 19.93 Ma W^-1 and detectivity of 7.21 × 10⁹ Jones, significantly exceeding the 6.73 mA W^-1 and 1.72 × 10⁹ Jones of thermally annealed devices. Additionally, SDGA-treated photodetectors retain 87% of their initial photocurrent after 30 days in air. SDGA establishes a transformative approach for robust and efficient perovskite-based optoelectronic applications.