Synthesis of a metal oxide with a room-temperature photoreversible phase transition

Abstract

Photoinduced phase-transition materials, such as chalcogenides, spin-crossover complexes, photochromic organic compounds and charge-transfer materials, are of interest because of their application to optical data storage. Here we report a photoreversible metal–semiconductor phase transition at room temperature with a unique phase of Ti3O5, λ-Ti3O5. λ-Ti3O5 nanocrystals are made by the combination of reverse-micelle and sol–gel techniques. Thermodynamic analysis suggests that the photoinduced phase transition originates from a particular state of λ-Ti3O5 trapped at a thermodynamic local energy minimum. Light irradiation causes reversible switching between this trapped state (λ-Ti3O5) and the other energy-minimum state (β-Ti3O5), both of which are persistent phases. This is the first demonstration of a photorewritable phenomenon at room temperature in a metal oxide. λ-Ti3O5 satisfies the operation conditions required for a practical optical storage system (operational temperature, writing data by short wavelength light and the appropriate threshold laser power). Optically driven phase transitions are widely used in optical memory devices, and the materials showing this effect are normally chalcogenides or organic compounds. Now a room-temperature light-induced phase transition between metal and semiconducting phases has been observed in a titanium oxide material.

Cite this article

Ohkoshi, Si., Tsunobuchi, Y., Matsuda, T. et al. Synthesis of a metal oxide with a room-temperature photoreversible phase transition. Nature Chem 2, 539–545 (2010). https://doi.org/10.1038/nchem.670

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