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Carrier transport dynamics from sub-50 ps to ∼μs over five temporal decades in pentacene films was studied by transient photoconductivity. The behavior of the temperature independent photocurrent peak suggests that the photogenerated carriers exhibit pre-trapping transport in extended states upon pulsed laser excitation. From 300 ps to ∼30 ns, the carriers thermalize and fall into shallow band tail states, and multiple-trapping and release transport dominates. From ∼30 ns to ∼μs, the weak temperature dependence of power-law photocurrent decay and the linear relation of logarithmic photocurrent with T−1/4 suggest a variable range hopping transport in deep trap states.

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Pd deposits on vitreous carbon substrates were prepared by electrodeposition from liquid crystal phases (both micellar and hexagonal phases) consisting of self-assembled non-ionic surfactant molecules. The morphology of the deposits varied significantly with the concentration of the surfactant but all are made up of aggregated nanoparticles circa 9 nm in diameter. The deposits from the micellar phase of the surfactant offer the largest electroactive area and specific activity for the hydrogen evolution, oxygen evolution and reduction reactions and formic acid and ethanol oxidations. Unexpectedly the deposits lead to an increase in catalytic activity far in excess of that expected from an enhancement in electroactive area.

the photoinduced charge carriers. [8][9][10] Besides, it is highly desirable to achieve these goals using earth-abundant materials and a cost-effective, energy-efficient, and scalable preparation strategy for large-scale photocatalytic systems.Recently, bismuth oxyhalides (BiOXs, X = Cl, Br, and I) have demonstrated excellent photocatalytic activity under sunlight irradiation due to their distinct characteristics such as indirect bandgap, excellent electronic configuration, unique layered structures, high dipole moment, powerful oxidation ability, and high separation rate of photogenerated electron-hole pairs. [11][12][13][14] Despite the distinct optical and structural characteristics of BiOXs, they show some drawbacks that limit their practical application. For instance, BiOBr has a narrow bandgap energy ≈2.7-2.8 eV absorbing the visible light component of the solar spectrum; however, its photocatalytic performance is relatively poor due to its low separation rate of charge carriers and weak oxidation ability. [8,15] On the other hand, BiOCl possesses a more powerful oxidation ability but with a wide bandgap energy (≈3.3 eV), thus responding to only UV light, which represents a small percentage (≈5%) of the solar spectrum, and reducing its chance for scalable remediation of environmental pollution. [16,17] Consequently, the integration of the desired characteristics of individual BiOXs in one photocatalytic compound is an effective strategy to produce more efficient BiOXs-based photocatalytic systems. For example, alloyed compounds (i.e., solid solutions) of BiOXs which contain more than one halogen atom in the compound through changes in the molar ratios of halogen atoms such as BiOCl x Br 1−x , [18,19] BiOCl x I 1−x , [20,21] and BiOBr x I 1−x . [22,23] have the same layered atomic structure, leading to the easy arrangement of different halogen atoms into the lattice of solid solutions using a low-energy fabrication process. Based on this fact, the solid solutions strategy is one of the most effective ways to improve the photocatalytic performance of BiOXs by reaching the best balance between the visible light absorption and reduction-oxidation (redox) abilities. [19,20,23] Among the different solid solutions of BiOXs, flower-like BiOCl x Br 1−x solid solutions (i.e., engineering BiOCl by introducing different molar ratios of Br) demonstrate superior photocatalytic performance compared to their counterparts. In previous studies, BiOCl x Br 1−x solid solutions were prepared by following two typical strategies, either by introducing organic salts (cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC)) as a source for halogen with different molar ratios using multistep methods at ambient conditions [19,24,25] or by using simple salts (KCl and KBr) as a source for halogen ions using the hydrothermal or solvothermal methods. [26][27][28] In fact, the first strategy is a lengthy process that requires expensive and complex organic materials as halogen sources and indisposable surfactants, ...