Memory effect of an organic photoconductor and its application to a neuron model

A new type of organic photoconductor composed of 9‐ethylcarbazole‐3‐carbaldehyde diphenylhydrazone (DPH) dispersed in a polycarbonate polymer (PCR) film, when in the presence of thio‐Michler’s ketone (TMK), was found to exhibit a sustained state of enhanced conductivity following visible irradiation. At room temperature, the enhanced current is observed to decay slowly over a period of a day and when heated it rapidly returns to its original state. A potential application of this ‘‘memory’’ effect to an artificial neuron model, using such memory‐type organic photoconductors as optically controllable interconnections, is discussed. A liquid‐crystal cell is used to demonstrate a nonlinear‐saturated response dependent on a weighted input electric signal.