This study investigates the potential of organic resistive memory technology to replicate biological synaptic functions in artificial neural networks. A metal–insulator–metal (MIM) device was fabricated using the organic dye Phenol Red sodium salt (PRSS) as the active layer sandwiched between indium tin oxide (ITO) and gold (Au) electrodes. The device exhibited stable write once read many (WORM) characteristics where the conducting filament cannot be ruptured, unlike a bipolar resistive switching (BRS) memory device. However, it successfully emulates essential synaptic behaviors, including learning (potentiation) and forgetting (depression) processes. The observed conductance modulation is attributed to a charge trapping and detrapping mechanism that reversibly alters the effective width of the conducting filament, distinct from the formation and rupture processes seen in BRS switches. Detailed characterizations were performed to analyze the nonlinearity factor (NLF) and the dependence of synaptic weight on pulse amplitude, width, and interval. The device demonstrated paired-pulse facilitation (PPF), a key form of short-term plasticity (STP), with the PPF index following a double-exponential decay relative to the pulse interval. Furthermore, repetitive cycling revealed the device’s capability for long-term potentiation (LTP), confirming its potential as a candidate for future memory storage and neuromorphic computing applications.
Das et al. (Wed,) studied this question.