Visual–Tactile Perception Enabled by Artificial Synapses Based on NIR Triggered Persistent Luminescence From Lanthanide Doped SrAl2O4

Persistent luminescence from lanthanide ions provides unique opportunities for information storage, optical sensing, and bio-inspired computing owing to excellent characteristics such as photothermal stabilities, tunable emission wavelengths, and long afterglow times. However, these materials suffer from insufficient near-infrared (NIR) excitation and multimodal regulation for neuromorphic applications. In this study, we developed a composite strategy that enables NIR-triggered and thermally regulated long-persistent luminescence (LPL) by coupling SrAl 2 O 4 :Eu 2+ ,Dy 3+ with NaYF 4 :Yb 3+ ,Tm 3+ . NIR-triggered synapses were achieved through radiative reabsorption between upconversion emission from NaYF 4 :Yb 3+ ,Tm 3+ and the excited state of SrAl 2 O 4 :Eu 2+ ,Dy 3+ , with a high paired-pulse facilitation (PPF) of 211% recorded when excited with 980-nm light. At the same time, LPL is modulated by thermally activated dynamics that release defect-trapped electrons. Moreover, information encryption, handwritten digit recognition, and manipulator gesture control were achieved based on artificial synapses that exploit the synergy between optical and thermal stimuli, with a recognition accuracy of up to 91.12% recorded. Moreover, a visual–tactile bimodal synapse that mimics the physiological response associated with grabbing a hot cup was developed. These findings facilitate potential multimodal synapse applications based on LPL in neuromorphic photonics, intelligent perception, and human–machine interactions.