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We demonstrate a new device that combines a light-field effect and an electrical-gate effect to control the drain current in a dual-gate transistor. We used two organic layers, photochromic spiropyran (SP)-doped poly(triarylamine) (PTAA) and pristine PTAA, as top and bottom channels, respectively, connected to common source and drain electrodes. The application of voltage to the top and bottom gates modulated the drain current through each layer independently. UV irradiation suppressed the drain current through the top channel. The suppressed current was then maintained even after the UV light was turned off because of an optical memory effect induced by photoisomerization of SP. In contrast, UV irradiation did not change the drain current in the bottom channel. Our dual-gate transistor thus has two organic channels with distinct photosensitivities: an optically active SP-PTAA film and an optically inactive PTAA film. This device configuration allows multi-level switching via top- and bottom-gate electrical fields with an optical-memory effect.

Porous silica with hierarchical macroporous and mesoporous architectures (MacroMeso-SiO2) was prepared by a solvent evaporation method using a precursor solution for synthesis of mesoporous silica (Meso-SiO2) and poly(methyl methacrylate) (PMMA) colloidal crystals as a hard template, and used as an advanced support of TiO2 photocatalyst. The porous structure and state of TiO2 was investigated by various characterization techniques. Reflecting the structure of aligned PMMA microspheres, MacroMeso-SiO2 have uniform and hierarchical macroporous structure with interconnecting networks even after loading of TiO2 particles. Based on the advantageous porous structure, TiO2-loaded MacroMeso-SiO2 exhibited specific characteristics, i.e., an easy transportation of relatively large molecules and unique adsorption properties to condense organic compounds, and enhanced photocatalytic properties in the degradation of organic compounds in water as compared to TiO2-loaded Meso-SiO2 under UV light irradiation. Graphical abstract 5Porous silica with hierarchical macroporous and mesoporous architectures can serve as an advanced material in the design of composite photocatalyst with TiO2 for purification of water.