Characterization of Si NCs and a perovskite-enhanced Si NC synaptic device. (a) Photograph of B-doped Si NCs in ethanol. (b) Low-resolution TEM image of Si NCs. The inset is the high-resolution TEM image of a Si NC. (c) Size distribution with a Gaussian fitting for Si NCs. The mean size of Si NCs is ~11.2 nm. (d) Schematic of a perovskite-enhanced Si NC synaptic device. The light that works as the optical stimulation incidents from the top of the device. (e) Cross-section SEM image of the synaptic device and EDS line scanning of the element of Pb. The thickness of the perovskite film and Si NC film is ~500 nm and~850 nm, respectively. (f) Cross-section distribution of the ratio of absorbed power per unit volume to total incident power of the synaptic device under the illumination of 532 nm laser.