Trap-Programmable Ruddlesden-Popper Perovskite Nanocrystals for Persistent Optoelectronic Memory and Photonic Synapses.

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 Csn +1CdnCl3 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.