Trap‐Programmable Ruddlesden–Popper Perovskite Nanocrystals for Persistent Optoelectronic Memory and Photonic Synapses

ABSTRACT Persistent luminescence offers a material‐native strategy for constructing non‐volatile optical memory. Nevertheless, embedding persistent luminescence functionality into solution‐processable optoelectronic platforms is still bottlenecked, as classic persistent phosphors suffer from poor film‐forming ability and low electrical conductivity for device integration. Herein, we report ligand‐free Sb‐doped Cs n +1 Cd n Cl 3 n +1 Ruddlesden–Popper perovskite nanocrystals (NCs), where the inorganic layer number ( n ) regulates local octahedral distortion and further tailors the intrinsic electron‐trap configuration. Benefiting from this precise structural modulation, the NC films achieve persistent luminescence with a duration over 5000 s and superior photoluminescence quantum efficiency. Combined spectroscopic characterization and first‐principles calculations reveal that the n ‐tuned crystal framework generates differentiated trap energy levels, which dominate carrier trapping, storage and radiative release kinetics. Finally, a long‐lived ultraviolet‐sensitive photonic synapse is achieved by integrating optimized n = 2 perovskite NCs with single‐walled carbon nanotube networks. The fabricated device features ultralong persistent photocurrent, 160% paired‐pulse facilitation ratio, slow charge decay dynamics, and visual image retention capability. This work establishes a scalable solution‐processed perovskite platform bridging structure‐customized trap states, ultralong‐lived optical memory, and optoelectronic synaptic behaviors, which paves a feasible pathway for developing integrated sensing‐memory neuromorphic architectures.