Deep Etching of Silicon Based on Metal-Assisted Chemical Etching.

A deep etching method for silicon "micro"structures was successfully developed. This wet etching process is based on metal-assisted chemical etching (MACE), which was previously mainly utilized to etch the features that have lateral dimensions of "nanometers." In this novel MACE, the critical improvement was to promote the "out-of-plane" mass transfer at the metal/Si interface with an ultrathin metal film.

Volatile organic compound gas sensors based on methylammonium lead iodide perovskite operating at room temperature.

Methylammonium lead iodide (MAPbI) perovskite thin film has been successfully applied to a volatile organic compound (VOC) gas sensor that can operate at room temperature. In this study, ∼100 nm-thick MAPbI film shows good reversibility and repeatability as a VOC gas sensor. The resistance of the MAPbI film substantially decreases when it is exposed to VOC vapour and recovers back to high resistance when the VOC gas is removed.

Ultrastable Photoelectrodes for Solar Water Splitting Based on Organic Metal Halide Perovskite Fabricated by Lift-Off Process.

Herein, we report an integrated photoelectrolysis of water employing organic metal halide (OMH) perovskite material. As generic OMH perovskite material and device architecture are highly susceptible to degradation by aqueous electrolytes, we have developed a versatile mold-cast and lift-off process to fabricate and assemble multipurpose metal encapsulation onto perovskite devices. With the metal encapsulation effectively protecting the perovskite cell and also functioning as electrocatalyst, the high-performance perovskite photoelectrodes exhibit high photovoltage and photocurrent that are effectively inherited from the original solid-state solar cell.

Integrated Photoelectrolysis of Water Implemented On Organic Metal Halide Perovskite Photoelectrode.

Herein we report on integrated photoelectrolysis of water employing organic metal halide (OMH) perovskite material. Generic OMH perovskite material and device architecture are highly susceptible to degradation by moisture and water. We found that decomposition of perovskite devices proceeds by water ingress through pinholes in upper layers and is strongly affected by applied bias/light and electrolyte pH.

Platinum monolayer electrocatalyst on gold nanostructures on silicon for photoelectrochemical hydrogen evolution.

Pt monolayer decorated gold nanostructured film on planar p-type silicon is utilized for photoelectrochemical H2 generation in this work. First, gold nanostructured film on silicon was spontaneously produced by galvanic displacement of the reduction of gold ion and the oxidation of silicon in the presence of fluoride anion. Second, underpotential deposition (UPD) of copper under illumination produced Cu monolayer on gold nanostructured film followed by galvanic exchange of less-noble Cu monolayer with more-noble PtCl6(2-).

Enhanced photoelectrochemical hydrogen production from silicon nanowire array photocathode.

Herein we report that silicon nanowires (SiNWs) fabricated via metal-catalyzed electroless etching yielded a photoelectrochemical hydrogen generation performance superior to that of a planar Si, which is attributed to a lower kinetic overpotential due to a higher surface roughness, favorable shift in the flat-band potential, and light-trapping effects of the SiNW surface. The SiNW photocathode yielded a photovoltage of 0.42 V, one of the highest values ever reported for hydrogen generation on p-type Si/electrolyte interfaces.

Comparison of the osteogenic potentials of autologous cultured osteoblasts and mesenchymal stem cells loaded onto allogeneic cancellous bone granules.

We compared the bone regeneration potentials of autologous cultured osteoblasts and of bone-marrow-derived autologous MSCs in combination with allogeneic cancellous bone granules in a rabbit radial defect model. Radial shaft defects over 15 mm were made in 26 New Zealand white rabbits. The animals underwent insertion of allogeneic cancellous bone granules containing autologous osteoblasts into right-side defects (the experimental group) and of allogeneic cancellous bone granules with autologous MSCs into left-side defects (the control group).