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The growing amount of data generated every year creates an urgent need for improved methods and new storage media. Far-field super-resolution techniques have provided the foundation for nanoscale 3D optical data storage towards a petabyte-level capacity on DVD-sized discs. However, a suitable recording medium for high-density information storage over long-term periods and with low energy consumption is still lacking. Rare-earth doped nanocrystals, which feature ladder-like-arranged energy levels enabling emission from ultraviolet to near-infrared, have a fluorescence lifetime two to three orders of magnitude longer than that of other fluorophores and offer the potential for low-power super-resolution data reading. Moreover, the reduction of graphene oxide to reduced graphene oxide induces permanent changes in its chemical and optical properties which can be used for data recording. Here, we demonstrate the reduction of graphene oxide induced by rare-earth doped nanocrystals via FRET towards super-resolution optical data storage with ultra-high capacity, ultra-long lifetime and ultra-low energy consumption. Yb3+/Tm3+-doped core-shell nanoparticles were synthesized via co-precipitation method and their fluorescence spectrum was obtained using a home-built microscope. A solution of rare-earth doped nanocrystals and graphene oxide nanoflakes was spin-coated on coverslip glass and fluorescence lifetime measurements were conducted to confirm efficient FRET. The reduction of graphene oxide was attributed to the transfer of energy quanta from up-converting rare-earth doped nanocrystals under 980-nm laser excitation. High-contrast images of the data bits were generated by super-resolution optical microscopy based on rare-earth doped nanocrystals due to the different degree of fluorescence quenching between graphene oxide and reduced graphene oxide.
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