Optical Input/Electrical Output Memory Elements based on a Liquid Crystalline Azobenzene Polymer

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• 作者：Thomas Mosciatti ; Sara Bonacchi ; Marco Gobbi ; Laura Ferlauto ; Fabiola Liscio ; Loris Giorgini ; Emanuele Orgiu ; Paolo Samorì
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 16, 2016
• 年：2016
• 卷：8
• 期：10
• 页码：6563-6569
• 全文大小：491K
• ISSN：1944-8252

文摘

Responsive polymer materials can change their properties when subjected to external stimuli. In this work, thin films of thermotropic poly(metha)acrylate/azobenzene polymers are explored as active layer in light-programmable, electrically readable memories. The memory effect is based on the reversible modifications of the film morphology induced by the photoisomerization of azobenzene mesogenic groups. When the film is in the liquid crystalline phase, the trans → cis isomerization induces a major surface reorganization on the mesoscopic scale that is characterized by a reduction in the effective thickness of the film. The film conductivity is measured in vertical two-terminal devices in which the polymer is sandwiched between a Au contact and a liquid compliant E-GaIn drop. We demonstrate that the trans → cis isomerization is accompanied by a reversible 100-fold change in the film conductance. In this way, the device can be set in a high- or low-resistance state by light irradiation at different wavelengths. This result paves the way toward the potential use of poly(metha)acrylate/azobenzene polymer films as active layer for optical input/electrical output memory elements.