The conduction band offset (CBO) of SnS as the light absorbing layer and Zn1−xMgxO as the buffer layer in SnS thin film solar cells has been optimized to improve the solar cell conversion efficiency. We controlled the CBO experimentally by varying the Mg content (x) of the Zn1−xMgxO layer. The optimum CBO value range for improved solar cell performance was determined to be from −0.1 to 0 eV. A SnS thin film solar cell sample with the optimum CBO value exhibited conversion efficiency of approximately 2.1%.

C2 production with conventional metal complex catalysts has been a significant challenge. Here, we present the electrochemical reduction of CO2 into C2 products such as ethylene and ethanol with high selectivity using a self-assembled cuprous coordination polymer nanoparticle (Cu-SCP). The features of the Cu-SCP catalyst are the arrangement of Cu atoms in close proximity, similar to that in metallic Cu, and a stable Cu­(I) oxidation state throughout the reaction due to the coordination of ligands with Cu atoms, which inhibits conversion into Cu metal particles. The Cu-SCP also exhibits activity for C2 production that is superior to that of a Cu metal electrode, without modification of the carbon particles and/or ionomers or continuous flow of the highly alkaline electrolyte, which will simplify the fabrication of a CO2 electrolyzer. The Cu-SCP can be synthesized by a facile process that utilizes a heterogeneous reaction, and the product selectivity can be changed by replacement of the organic ligands, which should open up possibilities for the design of other CO2 reduction catalysts.

received her bachelor and master degrees from Nara Women's University. She joined Toyota CRDL in 1992 and received he Ph.D. Degree from Tokyo Institute of Technology in 2009. Currently, she is a senior researcher of the Morikawa Senior Fellow Laboratory in Toyota CRDL. She has been working on development of inorganic catalyst materials for artificial photosynthesis. Takeshi MorikawaTakeshi Morikawa received his bachelor and master degrees from Nagoya University. He joined Toyota CRDL in 1989 and received his Ph.D. Degree in 2005. He has been working on development of sensors for automotive controls, magnetic materials, semiconductor photocatalyst, and CO 2 recycling systems by artificial photosynthesis. He is currently a manager of the Morikawa Senior Fellow Laboratory in Toyota CRDL. AbstractA highly crystalline, 10 nm-sized red rust water oxidation catalyst composed of pure β-phase FeOOH(Cl) nanorods (ca. 3 © 13 nm) doped with Ni ions (β-FeOOH(Cl):Ni) and surfacemodified with amorphous Ni(OH) 2 (a-Ni(OH) 2 , at a Ni to Fe ratio of 22 at.%) was synthesized by a facile one-pot process at room temperature. The overpotential during the electrochemical oxygen evolution reaction (OER) over the β-FeOOH:Ni/ a-Ni(OH) 2 stacked nanorod anodes was 170 mV, and an OER current of 10 mA/cm 2 was obtained at an overpotential of 430 mV in a 0.1 M KOH solution. X-ray absorption fine structure analysis, Mössbauer spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, X-ray diffraction and impedance spectroscopy suggested that surface modification with the a-Ni(OH) 2 lowered the OER overpotential of β-FeOOH(Cl):Ni, resulting in the very high current density at low potential compared with Fe-rich oxide and oxyhydroxide electrodes reported previously. Mössbauer spectroscopy suggested interaction between Fe and Ni species, which may be crucial evidence for the enhanced activity in the Fe-rich OER system.

No abstract

A p-type N-doped α-Fe2O3 was developed by magnetron sputtering of a Fe2O3 target in a plasma containing N2 and Ar followed by postannealing. Photoelectrochemical measurement under visible light irradiation (>410 nm) showed that N–Fe2O3 exhibits a typical cathodic photocurrent originated from the p-type conduction. X-ray photoemission spectroscopy indicated that the atomic N incorporated substitutionally at O sites was responsible for the p-type conduction. The concentration of acceptors was very close to that for Zn-doped Fe2O3, a typical p-type α-Fe2O3. This finding would stimulate further research on p-type Fe2O3 for solar fuel generation, etc.

This paper describes the observation of band bending and band edge shifts at the interfaces between nanoscale metals and TiO2 film over a wide depth range by angular-resolved hard X-ray photoemission spectroscopy (HAXPES). The HAXPES results indicate strong electrostatic interactions between the TiO2 semiconductor and metal nanoparticles, while density functional theory (DFT) calculations suggest that these interactions are primarily associated with charge transfer leading to electric dipole moments at the interface in the ground state. The effects of these dipole moments are not limited to the surface but also occur deep in the bulk of the semiconductor, and are highly dependent on the coverage of the metal nanoparticles on the semiconductor species.

No abstract

An Al 1%x Si x O y mixed oxide has been deposited on GaN by plasma-enhanced atomic layer deposition. The band diagrams between the mixed oxide and GaN for various Si atom fraction x values are determined by hard X-ray photoelectron spectroscopy for the first time. The band gap of the mixed oxide increases with increasing x. This dependence has a large bowing parameter of 1.5 eV. We have successfully obtained conduction band offset (ΔE C ) and valence band offset (ΔE V ) as a function of x: ΔE C (eV) = 1.6 + 0.4x + 1.2x 2 and ΔE V (eV) = 1.7 + 0.34x + 0.36x 2 . These relationships enable us to design GaN metal-oxide-semiconductor devices using the Al 1%x Si x O y mixed oxide.