Nondestructive readout of holographic memory in Ag/TiO2 heterojunction via carbon-dots and hydrogel co-modification

Effective utilization of light energy is essential for the storage and conversion of optical information. Plasmonic nanoparticles are regarded as an optical energy antenna for their spectrum-tuning ability, while the multi-wavelength response and interface electron flow, in turn, weaken the stability in reading information. Herein, we propose a smart route of carbon dot/hydrogel co-modified silver nanoparticles in titania to construct a large-area Schottky heterojunction. The diffraction efficiency is increased by three times, and the readout stability is even increased by 240 times, compared with those for undecorated Ag/TiO2 heterostructures. The readout fluctuation ratio of the holographic signal is less than 3% in the area of 1.5 × 1.5 cm2. The enhanced performance benefits from the interface electron regulation by carbon dots and the high stability of Ag+ ions in hydrogel. Based on such properties, an 8-cm plasmonic holographic disk is fabricated, opening a bright way to the application of high-density information memory.