article epub_ahead yes Subham Saha author Shreyasi Das author c102f9d5-4f26-11ef-94d5-9047d2a9105b Baidyanath Roy author Santu Kumar Ghosh author Rohit Satpathy author James Bullock author Ranjith R. Unnithan author Samit K. Ray author HrPo department Bio-inspired photonic synapses integrate optical sensing, memory, and processing in a single platform, overcoming the bottlenecks of traditional CMOS-based vision sensors. Most existing neuromorphic vision systems either rely on electrical inputs for bidirectional conductance modulation, limiting their operating speed and bandwidth, or lack nonvolatility, leading to nonlinear weight updates and poor efficiency in image recognition tasks. Here, we report a two-terminal, fully light-controlled synaptic memristor based on CsPbBr3/ZnO nanorod heterojunction that demonstrates 4-bit memory storage and optical logic operations within a single architecture. The device emulates essential functions of both excitatory and inhibitory synapses, utilizing positive photoconductivity under UV illumination (λ = 375 nm) and anomalous negative photoconductivity under visible light (λ = 450 nm). By controlling defect concentrations at the CsPbBr3/ZnO nanorod interface, the device exhibits nonvolatile multibit memory with near-linear, symmetric conductance modulation, achieving 92.4% image recognition accuracy with a convolutional neural network. The bidirectional photoresponse enables reconfigurable optical logic operations, demonstrating integrated logic-in-memory. Additionally, when integrated on a flexible platform, the device demonstrates stable synaptic performance under repeated mechanical bending. These results highlight the potential of CsPbBr3/ZnO nanorod heterojunction-based all-photonic synapses as building blocks for multibit storage, optical information processing, and wearable neuromorphic vision systems. Wiley2026 eng all-optical synapsebidirectional photoresponsedefect engineeringflexible neuromorphic visionmultibit nonvolatile memorynegativephotoconductivityoptical logic gate 1613-6810 1613-6829 4264300410.1002/smll.75437 Saha, Subham, Shreyasi Das, Baidyanath Roy, Santu Kumar Ghosh, Rohit Satpathy, James Bullock, Ranjith R. Unnithan, and Samit K. Ray. “Interface Engineered Perovskite-Oxide Heterojunction All-Photonic Synapses for Multibit Memory, Optical Logic, and Wearable Neuromorphic Vision.” <i>Small</i>. Wiley, 2026. <a href="https://doi.org/10.1002/smll.75437">https://doi.org/10.1002/smll.75437</a>. S. Saha, S. Das, B. Roy, S.K. Ghosh, R. Satpathy, J. Bullock, R.R. Unnithan, S.K. Ray, Small (2026). S. Saha <i>et al.</i>, “Interface engineered perovskite-oxide heterojunction all-photonic synapses for multibit memory, optical logic, and wearable neuromorphic vision,” <i>Small</i>. Wiley, 2026. Saha, S., Das, S., Roy, B., Ghosh, S. K., Satpathy, R., Bullock, J., … Ray, S. K. (2026). Interface engineered perovskite-oxide heterojunction all-photonic synapses for multibit memory, optical logic, and wearable neuromorphic vision. <i>Small</i>. Wiley. <a href="https://doi.org/10.1002/smll.75437">https://doi.org/10.1002/smll.75437</a> Saha, Subham, et al. “Interface Engineered Perovskite-Oxide Heterojunction All-Photonic Synapses for Multibit Memory, Optical Logic, and Wearable Neuromorphic Vision.” <i>Small</i>, e75437, Wiley, 2026, doi:<a href="https://doi.org/10.1002/smll.75437">10.1002/smll.75437</a>. Saha S, Das S, Roy B, et al. Interface engineered perovskite-oxide heterojunction all-photonic synapses for multibit memory, optical logic, and wearable neuromorphic vision. <i>Small</i>. 2026. doi:<a href="https://doi.org/10.1002/smll.75437">10.1002/smll.75437</a> Saha S, Das S, Roy B, Ghosh SK, Satpathy R, Bullock J, Unnithan RR, Ray SK. 2026. Interface engineered perovskite-oxide heterojunction all-photonic synapses for multibit memory, optical logic, and wearable neuromorphic vision. Small., e75437. 228192026-09-06T22:01:58Z2026-09-09T13:40:30Z