Spectrophotometric characterization of organic memristive devices

Abstract Realizing element able to mimic some features of the human brain is a challenging perspective. The concept of organic devices, based on conductive polymers, is attracting significant interest being generally bio-compatible, able to work in liquid phase, with low bias voltage ranges. Organic memri-stive devices have demonstrated the capability of mimicking some properties of biological synapsis. Moreover, memristive devices based on polyaniline (PANI) have been used as artificial synapsis in the hardware of a single layer perceptron. In the perspective of a multi-layered perceptron, a fundamental step is the knowledge of the conductive state of each single memristor. The electrochromicity of PANI endows us to developed a non-invasive and precise method to solve this problem; in fact, PANI memristor's state (induced by the voltage biasing) can be monitored measuring its optical features variation by means of a spectrophotometer. The latter, thanks to its high accuracy, allows distinguishing minimal color variation at a micrometric distance and, without lowering its precision, can measure areas of 7 × 60 cm2 in a single scan and reach, in several scans, a total area of 120 × 140 cm2. Therefore, in future works we will extend the here proposed method in order to get, in a single scan, contact-less measurement and information about the state of each single PANI memristor belonging to a multi-layered perceptron.