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The four-center complex with the [N–Os–Os–N] array shows four consecutive redox processes at relatively low potentials. The corresponding five redox states are characterized by significantly different absorption spectra in the visible and near-infrared region.

Recent advances in one-pot solution synthesis of multi-shelled transition metal oxide hollow structures are highlighted here.

Two new conjugated copolymers, PFPh and PFTDP, comprised of alternating 9,9-dioctylfluorene and phthalimide (Ph) or thieno [3, 4-c] pyrrole-4,6-dione (TPD) have been synthesized via Suzuki coupling reaction. Polymeric light-emitting diodes (PLED) were fabricated with an ITO/PEDOT: PSS/PVK/Polymer/BCP/Alq/Ca:Ag configuration. The maximum brightness and maximum current efficiency of PLED are 2600cd/m2 and 2.52 cd/A for PFPh, and 2300cd/m2 and 1.13 cd/A for PFTDP, respectively, which are significantly improved compared with the reported alternating fluorene-unsubstituted phenylene/thiophene systems.

A novel highly ordered layered superlattice multibilayer film is prepared by casting the chloroform solutions of ionic complex between a polyoxotungstoeuropate anion EuW₁₀O₃₆9− (EuW₁₀) and a hexadecyltrimethylammonium cation (C₁₆TA) on hydrophilic substrates. A variety of techniques, including FT-IR and UV–vis spectroscopies, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to characterize the structure of the composite film. The lamellae consist of alternating layers of polyoxotungstoeuropate and bimolecular layers of surfactant, with the surfactant alkyl chains tilted 30.8° to the lamellar surface and noninterdigititated. The photoluminescent behavior of the film at room temperature has also been investigated by fluorescence spectroscopy to show the characteristic Eu3+ emission pattern of 5D₀ → 7F_j. The fluorescence spectra and fluorescence lifetime of the composite film are quite different from those found for EuW₁₀ solid powder and EuW₁₀ dilute aqueous solution.

A layered superlattice, WO₃-polymer/1,10-decanediamine (1,10-DDA) self-assembled multilayer film, has been fabricated by means of alternating adsorption of tungstic acid and 1,10-DDA. The growth process, structure, and photochromic properties of the self-assembled multilayer film have been investigated and compared with those of the previously reported WO₃/4,4'-bis(aminomethyl)biphenyl (4,4'-BAMBp) system. It was found that the exciting improved photochromic properties of WO₃-polymer/1,10-DDA films result from the polymerization of WO₃ molecules in the inorganic layers. The results clearly show that the organic molecules can efficiently manipulate the microstructure of the inorganic layer as well as the photochromic properties of the self-assembled multilayer films.

A highly ordered multilayer film was formed by casting chloroform solutions of an ionic complex between a dimethyldioctadecylammonium (DODA) and a phosphomolybdate anion PMo₁₂O₄₀3− (PMo₁₂) on a glassy carbon electrode and solid substrates (CaF₂, quartz, and borosilicate glass). A well-ordered lamellar superlattice structure was identified by X-ray diffraction (XRD) and differential scanning calorimetry (DSC) experiments. IR spectra showed that the Keggin structure of the phosphomolybdate anion is preserved in the composite film. The superlattice film showed good photochromic and electrochemical properties. Irradiated with UV light, the transparent film changed from colorless to blue. Then, bleaching occurred when the film was in contact with ambient air or O₂ in the dark. A possible photochromic mechanism was proposed according to electron paramagnetic resonance (EPR), Fourier transform infrared spectra (FTIR), UV–vis spectra, and related literature. The electrochemical behavior of the composite film was also examined by cyclic voltammetry in detail.

Phosphotungstic acid (PW12) and 1,10-diaminodecane (1,10-DAD) molecules have been alternatively assembled on 3-aminopropyltriethyoxysilane modified quartz or silicon substrate to form multicomposite mutilayer thin films by the molecular deposition technique. Thus-obtained films were characterized by UV-visible, XRD, X-ray reflection (XRR), and XPS spectra. Results show that the layer-by-layer self-assembly of PW12and 1,10-DAD leads to a well-ordered superlattice-layered structure with a d-spacing of 3.19 nm, which exhibits extremely exciting photochromic properties. Based on the experimental data, a presumable interlayer structural model has also been suggested.

1,5-Diphenyl-3-naphthyl-2-pyrazoline nanocrystals with different sizes from 400 to 20 nm were prepared by the reprecipitation method. As the nanocrystal size decreased, the nanocrystal absorption peak was observed to shift to high-energy side due to size effect, and in the same period the peak shape changed from asymmetric to symmetric due to the gradual disappearance of the aggregate absorption.

A WO₃/Au composite thin film is prepared by depositing gold nanoparticles onto the surface of a vacuum-evaporated WO₃ thin film through a spin-coating technique. It is found that the photochromism of the WO₃ thin films are enhanced greatly after the modification with Au nanoparticles. The enhancement effect is explained according to the Schottky barrier formed at the WO₃/Au interface and the surface effect of the gold nanoparticles. The results may be helpful in technical applications and provide a more detailed understanding of the photochromic mechanism.

A one-pot reaction design is proposed in this paper for synthesis of layered polymer/MoO3materials. The experimental results evidenced the availability of this design. By using acidified ammonium molybdate as precursor of the inorganic hosts and FeCl3as the oxidizing agent of aniline, layered PANI/MoO3has been obtained via a one-step coprecipitation route.

1,3,5-Triphenyl-2-pyrazoline microcrystals with different sizes from 300 nm to 30 nm were prepared by the reprecipitation method and their absorption peak was found to shift to higher energy side with decreasing crystal size due to size effect and J-aggregate effect.