Bidirectional Photochromism via Anchoring of Carbon Dots to TiO2 Porous Films.

Photochromic materials present photocontrollable properties, which is of great interest for potential applications including high-density storage and optical displays. Herein, we demonstrate a promising pathway toward smart photochromic nanocomposite exploration by anchoring of carbon dots (CDs) to titanium dioxide (TiO2) porous films. This study reveals that the color of the CDs/TiO2 film obtained by dropping anchoring becomes darker and that obtained by immersion anchoring becomes lighter, both under blue light irradiation. For the photobleaching material system, the spectral response is strongly dependent on wavelength and polarization of the exciting light, which provides new dimensions for optical information encryption and memory. This work lays the foundation for the materials platform in the integration of advanced information processing in the future.