Development of Multilevel Organic Phototransistor Memory using Conjugated/Insulating Polymer Blends with a Vertical Phase Separation

Abstract

AbstractIn this work, a series of methacrylate‐based polymers bearing benzene (poly(benzyl methacrylate)), naphthalene (poly(2‐naphthyl methacrylate)), anthracene (poly(9‐anthracenyl methyl methacrylate), PAMA), and pyrene (poly(1‐pyrenemethyl methacrylate)) are blended with conjugated polymer of poly(3‐hexylthiophene) (P3HT) to perform vertical phase separation during spin‐coating. The bilayer structure of the conjugated/insulating polymer blend is driven by their mismatch in surface energy, and the blend films are applied in the phototransistor memory device with the bottom layer of methacrylate‐based polymer as a photoactive electret and the top layer of P3HT as a semiconducting channel. It is found that the vertical phase separation morphology, conjugation, and energy levels of the pendant arene groups in the methacrylate‐based polymers are highly related to the photoresponse, memory retention/endurance of the phototransistor memory. Therefore, the device comprising the polymer blend of P3HT and PAMA successfully produces a high current contrast of 105 to 254 nm light and 104 to 450 nm light over 104 s. This study provides a facile approach to the fabrication of high‐performance phototransistor memory devices.