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Fe2O3 short nanorods, nanorods and nanowires were prepared by a facile hydrothermal method by using different flexible ligands (oxalic acid, succinic acid, adipic acid) as templates to adjust the L/D (length/diameter) ratios of the one-dimensional (1D) Fe2O3–nanostructures for the first time. The growth mechanism of Fe2O3 nanorods and nanowires were proposed. Their potential applications as anodes for lithium ion batteries were investigated by electrochemical analysis. This novel straightforward strategy to fabricate 1D metal oxide with different L/D ratios may provide a promising method to make advanced Fe2O3-based nanostructures for Li-ion battery applications. [ABSTRACT FROM AUTHOR]

Thetwo- and three-photon detachment of negative silver ions in a femtosecondinfrared laser field is studied using photoelectron velocity map imagingmethods. Photoelectron angular distributions (PADs) are obtained forthese detachment channels; these PADs change dramatically when thelaser wavelength and intensity are changed. Theoretical predictions,which are based on the adiabatic Keldysh–Faisal–Reisssaddle point method, are in good agreement with our experiment. Thedependence of the PAD on the laser wavelengths and intensities isdue to the interference between the different partial wave functions.The relative contributions of the different partial waves to the detachmentamplitude are altered by changing the laser parameters and, as a result,the shape of the PAD. Close to the detachment threshold, the two-photondetachment process also follows the Wigner threshold law. Near thedetachment threshold, the large differences between the calculatedresults and our experimental results indicate that the ponderomotiveenergy shifts caused by the femtosecond laser fields must be takeninto account in the theoretical model. The three-photon detachmentof Ag–is also observed and compared with theoreticalcalculations. [ABSTRACT FROM AUTHOR]

High performance p -GaN/oxide layer/ n -GaN ultraviolet (UV) photodetector was fabricated in this paper. The UV detector composed of n -GaN and p -GaN film with oxide layer which was constructed by directly contacting way. The detector based on GaN p -GaN/oxide layer/ n -GaN structure showed high UV response with fast speed. The results indicated that the fabrication of large-scale GaNbased materials was greatly facilitated with relatively low cost contacting method. Furthermore, it offered a new method to obtain UV detector for GaN-based materials with high performance.

The ultrafast transfer of plasmon-induced hot electrons is considered an effective kinetics process to enhance the photoconversion efficiencies of semiconductors through strong localized surface plasmon resonance (LSPR) of plasmonic nanostructures. Although this classical sensitization approach is widely used in noble-metal-semiconductor systems, it remains unclear in nonmetallic plasmonic heterostructures. Here, by combining ultrafast transient absorption spectroscopy with theoretical simulations, IR-driven transfer of plasmon-induced hot electron in a nonmetallic branched heterostructure is demonstrated, which is fabricated through solvothermal growth of plasmonic W 18 O 49 nanowires (as branches) onto TiO 2 electrospun nanofibers (as backbones). The ultrafast transfer of hot electron from the W 18 O 49 branches to the TiO 2 backbones occurs within a timeframe on the order of 200 fs with very large rate constants ranging from 3.8 × 10 12 to 5.5 × 10 12 s -1 . Upon LSPR excitation by low-energy IR photons, the W 18 O 49 /TiO 2 branched heterostructure exhibits obviously enhanced catalytic H 2 generation from ammonia borane compared with that of W 18 O 49 nanowires. Further investigations by finely controlling experimental conditions unambiguously confirm that this plasmon-enhanced catalytic activity arises from the transfer of hot electron rather than from the photothermal effect., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The photoionization dynamics of pyrrole are investigated by using a photoelectron imaging method and a tunable femtosecond laser. Two-photon nonresonant ionization experiments in the wavelength range from 261 to 298 nm indicate that the cation and neutral ground states have similar structures. The main vibrational excitation in the cation ground state is the v(8) mode. Two-photon absorption at 406 nm projects neutral pyrrole into a mixed state comprising the 1B(2) valence and 3p Rydberg states. Ionization from this mixed state mainly results in the overtone excitation of vibrational mode v(8) and v(9) of the cation state. In the wavelength range from 336 to 364 nm, a mixed state comprising the 3d/4s Rydberg and the 4A(1) valence states are populated by the absorption of two photons through vibronic coupling. The partition ratio among these states varies with the excitation wavelength, resulting in dramatic changes in both kinetic energy distributions and angular distributions. As the laser wavelength becomes shorter, from 336 to 314 nm, higher excited states, 3B(2), 5A(1), 6A(1), 7B(1) and 4B(2), can be populated. Photoelectron angular distributions provide supplementary verification of assignments. Our experiments indicate that femtosecond multiphoton ionization and photoelectron imaging methods are powerful tools for investigating short-lived intermediated excited states, which cannot be detected in nanosecond experiments.