Organic emitters with persistent phosphorescence have shown potential application in optoelectronic devices. However, rational design and phosphorescence tuning are still challenging. Here, a series of metal-free luminophores without heavy atoms and carbonyl groups from commercial/lab-synthesized carbazole and benzene were synthesized to realize tunable molecular emission from fluorescence to phosphorescence by simply substituent variation. All the molecules emit blue fluorescence in both solution and solid state. Upon removal of excitation source, the fluorinated luminophores show obvious phosphorescence. The labsynthesized carbazole based molecules exhibit a huge lifetime difference to the commercially purchased ones due to the existence of isomer in the latter samples. The small energy gap between singlet and triplet state and low reorganization energy help enhance intersystem crossing to contribute to a more competitive radiative process from triplet to ground state. Blue and white organic light-emitting devices are fabricated by using fluorinated luminophore as emitting layer.

AgI/AgCl/H 2 WO 4 double heterojunctions photocatalyst was prepared via deposition-precipitation followed by ion exchange method. The structure, crystallinity, morphology, chemical content and other physical-chemical properties of the samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectra (EDX), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL). The photocatalytic activity of the AgI/AgCl/H 2 WO 4 was evaluated by degrading methyl orange (MO) under visible light irradiation ( > 400 nm). The double heterojunctions photocatalyst displayed more efficient photocatalytic activity than pure AgI, AgCl, H 2 WO 4 and AgCl/H 2 WO 4 . Based on the reactive species and energy band structure, the enhanced photocatalytic activity mechanism of AgI/AgCl/H 2 WO 4 was discussed in detail. The improved photocatalytic performance of AgI/AgCl/H 2 WO 4 double heterojunctions could be ascribed to the enhanced interfacial charge transfer and the inhibited recombination of electron-hole pairs, which was in close relation with the AgI/AgCl/H 2 WO 4 heterojunctions formed between AgI, AgCl and H 2 WO 4 .