Overcoming the Centrosymmetry Challenge: Trap Banking Enables Mechanoluminescence in Mn 2+ ‐Doped Halide Perovskites

ABSTRACT Mechanoluminescence, the direct conversion of mechanical energy into light, has traditionally been restricted to non‐centrosymmetric crystals where intrinsic piezoelectric fields drive carrier separation. This constraint has excluded the class of halide perovskites, despite their exceptional optoelectronic versatility and mechanical softness, because their centrosymmetric lattices forbid the required polar response. Here we introduce a fundamentally different paradigm, termed trap banking, that circumvents the symmetry requirement by dividing charge storage between intrinsic electron traps and Mn 2+ hole‐trapping centers. In the model system Cs 3 Cd 2 Cl 7 , ultraviolet pre‐charging populates intrinsic electron reservoirs within the host framework, while Mn 2+ dopants serve simultaneously as deep hole‐trapping centers and luminescent activators. Mechanical stimulation subsequently liberates the stored electrons, enabling non‐radiative energy transfer to the Mn 2+ 4 T 1 excited state and yielding bright orange‐red emission via the 4 T 1 → 6 A 1 transition. The mechanoluminescence intensity exhibits a linear dependence on applied force and withstands repeated cycling without degradation. This trap banking strategy effectively overcomes the centrosymmetry barrier and establishes a blueprint for engineering mechanoluminescence in soft halide perovskites. We further showcase the potential value of this approach through camera‐based force distribution imaging and AI‐enhanced retrieval of handwritten pressure information, paving the way toward self‐powered mechanical sensors, wearable health monitors, and advanced anti‐counterfeiting technologies.