High-stable plasmonic holographic memory controlled by Ta₂O₅/TiO₂ heterojunction

Regulation of optical reversibility is always a fascinating topic. For noble-metal/semiconductor system, bidirectional photochromism weakens the stability of information storage. How to control interfacial electron transfer has become a big challenge for permanent memory. Herein, we construct Ag/Ta₂O₅/TiO₂ dual-heterojunction films as nonvolatile holographic elements. Ta₂O₅/TiO₂ heterojuction plays a role of electron trap to receive the UV-excited electrons in the system. The size distribution of the deposited Ag nanoparticles is widened after introducing Ta₂O₅ onto TiO₂ nanoporous films, accompanied with the improved absorbance in long-wavelength region and enhanced plasmonic surface resonance. Based on such properties, the dual-heterojunction holographic element resists UV damage effectively. Under the repeated stimulus of UV/visible light, it is exhibited that the holographic data retention is gradually enhanced. This work provides a bright way to smart storage and artificial synaptic photonic devices.