Enhanced Photoluminescence in a Neuromorphic 2D Memitter Based on WS via Plasmonic Nanoparticle Self-Assembly.

All-optical neuromorphic devices based on adaptive two-dimensional (2D) materials have the potential for mimicking the complex processing and memory capabilities of biological synapses. Recent research demonstrated synaptic plasticity and visual memory in WS monolayer-based 2D memitters (i.e., an emitter with memory). However, improving their optical performances is crucial for extending their scalability. Since the neuromorphic functionalities of 2D memitters relies on O and HO desorption/absorption on WS, a careful balance between photoluminescence intensity and surface preservation is critical. Here, we investigate the enhancement of time-dependent photoluminescence response, achieved through coupling WS flakes with plasmonic nanoparticles obtained by liquid phase infiltration of gold in self-assembled block copolymer micelles. The localized surface plasmon resonance of gold nanoparticles amplifies the electric field and improves light-matter interactions. This method enhances the 2D memitter optical properties while preserving its adaptive photoluminescence response, thus enabling neuromorphic behavior under optical stimuli.