The Role of the Internal Capacitance in Organic Memristive Device for Neuromorphic and Sensing Applications

Organic electronics has recently emerged as a promising candidate for the emulation of brain-like functionalities, especially at the device level. Among the proposed technologies, memristive devices have gained an increasing attention due to their non-volatile behavior which makes them suitable for the implementation of artificial neuronal networks. However, most of them have an energy-costly switching mechanism which limits the approach of brain like energy efficiency. Different from them, organic memristive devices (OMDs) have a narrow switching window and implement neuromorphic characteristics at voltages <= 1 V. Despite OMDs potentialities in bioinspired electronics, guidelines for the design of devices and materials are still missing. Here it is shown that the device capacitance represents a significant degree of freedom for targeting devices applications. It is also shown that a single OMD emulates activity dependent synaptic functions and neuronal temporal and spatial summation, taking advantage of its three-terminals configuration. Interestingly, despite the neuromorphic applications, OMDs can also sense and amplify incoming signals on the basis of their capacitive and/or resistive values. This spectrum of applications, ranging from volatile to non-volatile characteristics and from neuromorphic computing to bio signals sensing, sets the stage for the realization of integrated circuits for adaptive sensing.