The one- and two-photon luminescence of stilbene-type solid-state materials can be tuned and controlled from blue to yellow color by a supramolecular cocrystal method.

This paper describes the photoelectrochemical response in aqueous electrolyte of nitrogen-doped titanium dioxide, TiO2 - x N x . Thin film electrodes were prepared by reactive DC magnetron sputtering in an environment of Ar, O2, and N2. A typical film thickness was 0.85 μm. The crystal structure of the photoelectrochemically active films was mainly of rutile character, and scanning and transmission electron microscopy showed a highly porous parallel penniform nanostructure. It was conclusively shown that dioxygen could be generated from water by illumination of the TiO2 - x N x electrodes at moderate anodic potentials. The current density under 1000 W m-2 visible light from a sulfur lamp was 0.2 mA cm-2 at 0.55 V vs Ag/AgCl. Current−voltage characteristics under illumination were strongly dependent on the scan direction. Scanning the electrode from cathodic toward anodic potentials gave an onset potential similar to that of normal rutile TiO2, whereas a reversed scan gave an onset of photocurrent (depending on the light source) anodically upshifted by up to 0.8 V from its normal position. Moreover, a cathodic current was observed during the latter scans. This current was induced by the illumination at anodic potentials. This nonfaradic current was ascribed to photoinduced electron trap states distributed in an approximately 1.3 V wide range negative of the conduction band (CB) edge. These states also were active as electron−hole recombination centers. The density of this new set of states was ∼2 × 1020 cm-3, i.e., similar to the density of nitrogen atoms. They can be activated by light, even at wavelengths beyond 700 nm, and work as long-lived electron traps; hence, they have properties that are different from those of the earlier found Ti3+ (3d) states, also located below the CB of TiO2. The new states occur as a consequence of the nitrogen doping, but is not necessarily an intrinsic property of pure TiO2 - x N x . Recombination via the new statesin conjunction with slow hole transport in the nitrogen-created band above the valence band edgewas suggested to be the cause of the large anodic shift of the onset potential for cathodic scans and of the moderate water oxidation efficiency of the TiO2 - x N x thin film electrodes.

We report a biomorphic hierarchical mixed metal oxide (MMO) framework through a biotemplated synthesis method. A uniform Al 2 O 3 coating was deposited on the surface of the biotemplate with an atomic layer deposition (ALD) process, and the film of ZnAl-layered double hydroxide (ZnAl-LDH), which faithfully inherits the surface structure of the biotemplate, was prepared by an in situ growth technique. Subsequently, a polycrystal ZnAl؊MMO framework obtained by calcination of the LDH precursor has been demonstrated as an effective and recyclable photocatalyst for the decomposition of dyes in water, owing to its rather high specific surface area and hierarchical distribution of pore size. Therefore, the new strategy reported in this work can be used to fabricate a variety of biomorphic LDHs as well as MMO frameworks through replication of complicated and hierarchical biological structures for the purpose of catalysis, adsorbents, and other potential applications.

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Luminescent films have received great interest for chemo-/bio-sensing applications due to their distinct advantages over solution-based probes, such as good stability and portability, tunable shape and size, non-invasion, real-time detection, extensive suitability in gas/vapor sensing, and recycling. On the other hand, they can achieve selective and sensitive detection of chemical/biological species using special luminophores with a recognition moiety or the assembly of common luminophores and functional materials. Nowadays, the extensively used assembly techniques include drop-casting/spin-coating, Langmuir-Blodgett (LB), self-assembled monolayers (SAMs), layer-by-layer (LBL), and electrospinning. Therefore, this review summarizes the recent advances in luminescent films with these assembly techniques and their applications in chemo-/bio-sensing. We mainly focused on the discussion of the relationship between the sensing properties of the films and their architecture. Furthermore, we discussed some critical challenges existing in this field and possible solutions that have been or are being developed to overcome these challenges.