Precisely Regulating Photoactivated Dynamic Room Temperature Phosphorescence by Alkyl Chain‐Induced Lattice‐Softening

Abstract Dynamic response room temperature phosphorescence (RTP) is a hot topic in smart materials research due to its unique RTP‐response characteristics under external stimuli. However, its precisely control are currently challenging. Here, an alkyl chain‐induced lattice‐softening strategy is proposed to precisely regulate photoactivated dynamic RTP (PDRTP). By adjusting the alkyl chain flexibility of hybrid metal halide matrices, oxygen permeability can be adjusted, thereby achieving finely manipulate of the photoactivation equilibrium time, RTP lifetime, and RTP wavelength of the resulted host–guest doped materials within the ranges of 10–600 s, 0.05‐1.62 s, and 405–595 nm, respectively. It is also demonstrated the potential application of the PDRTP materials in afterglow oxygen sensing and multi‐level information encryption. This study not only proposes an effective method for regulating the photosensitivity of PDRTP materials, but also points out a new direction for exploring gas permeability in dense‐packed crystalline materials.