All-Inorganic Artificial Optical Synapse Based on CsPbBr3 QDs

In this work, CsPbBr3 QDs were successfully prepared and used as the functional layer of all-light-controlled synaptic devices with a two-terminal structure of Ag/CsPbBr3 QDs/FTO, which achieved systematic artificial synaptic functions under 405 nm and 532 nm light irradiation with the optical power of 4 mW. The typical synaptic properties including excitatory postsynaptic current (EPSC), pairing pulse facilitation (PPF), spike number-dependent plasticity (SNDP), and spike rate-dependent plasticity (SRDP) can be obtained. The short-term memory (STM) and long-term memory (LTM) phenomena can be observed through the SNDP measurement. Subsequently, the effects of different light wavelengths and powers on synaptic performance have been investigated. The consistency and durability of the all-light-controlled CsPbBr3 QDs-based synaptic device were tested, demonstrating good stability. Furthermore, we also explored the potential of CsPbBr3 QDs-based synaptic devices in convolutional neural networks (CNN) and studied the changes in image recognition accuracy under stimulation by light pulses of different wavelengths. After 50 trainings, the image recognition accuracy were 92.74% (405 nm) and 86.05% (532 nm), respectively. This study is expected to promote the development of artificial intelligence in the future.