Preparation Of Large-area Films Research Articles

One-Step Preparation of Large Area Films of Oriented MoS₂ Nanoparticles on Multilayer Graphene and Its Electrocatalytic Activity for Hydrogen Evolution.

MoS2 is a promising material to replace Pt-based catalysts for the hydrogen evolution reaction (HER), due to its excellent stability and high activity. In this work, MoS2 nanoparticles supported on graphitic carbon (about 20 nm) with a preferential 002 facet orientation have been prepared by pyrolysis of alginic acid films on quartz containing adsorbed (NH4)2MoS4 at 900 °C under Ar atmosphere. Although some variation of the electrocatalytic activity has been observed from batch to batch, the MoS2 sample exhibited activity for HER (a potential onset between 0.2 and 0.3 V vs. SCE), depending on the concentrations of (NH4)2MoS4 precursor used in the preparation process. The loading and particle size of MoS2, which correlate with the amount of exposed active sites in the sample, are the main factors influencing the electrocatalytic activity.

Low-temperature Synthesis of Large-area Films of Molybdenum Trioxide Microbelts in Air and the Dependence of Their Field Emission Performance on Growth Conditions

A simple method is introduced for the preparation of large-area films of molybdenum trioxide (MoO 3 ) micro-belts. It is found that such films can be grown on indium tin oxide (ITO) glasses or silicon substrates at low temperatures by thermal evaporation deposition in air without using catalyst. Field emission measurements show that the turn-on field of the MoO 3 microbelts is as low as 2.2 V/μm required to obtain a current density of 10 μA/cm 2 . The combination of the simplicity of the growth method and the attractive field emission performance makes it a potential low-cost technique for the preparation of large-area field emission cold cathode material.

Electrochemical Preparation of p-Type Cupric and Cuprous Oxides on Platinum and Gold Substrates from Copper(II) Solutions with Various Amino Acids

p-Type cupric oxide has been deposited electrochemically on platinum and gold electrodes from Cu(II) solutions containing various amino acids, which is very attractive because the procedure is simple and the preparation of large-area film is possible. This indicates that the anodic deposition of CuO takes place simultaneously with the oxygen evolution and the extent of participation of each reaction depends on the stability and structure of Cu(II)-amino acid complex, pH, electrode potential, etc. The grain size of CuO obtained in the presence of glycine, which was estimated from the diffraction peak of (110), was found to be smallest (12 nm) among those acquired with various amino acids, suggesting that the electrodeposition of CuO from Cu(II)-Gly solution leads to the formation of a denser film. Furthermore, it was revealed that the CuO prepared here possesses a property like a p-type semiconductor. The photoelectrochemical reduction of CuO to was confirmed by analysis with X-ray diffraction. © 2002 The Electrochemical Society. All rights reserved.

The preparation of large area films for bubble domain devices

The growth of LPE films 3.8 cm in diameter has been achieved under conditions which lead to a high yield of defect free material suitable for bubble domain circuits. Temperature control to ±0.1°C, larger melt volumes, more precise timing of runs and an increase in saturation temperature of the melt to 970°C all contribute to the improved quality. The change to 970°C also sharply reduces platinum attack. Films having a collapse field controlled to ±1 Oe can be grown in yields exceeding 35%.