Properties of ZnSe films pulse electrodeposited in the presence of phosphotungstic acid

ZnSe films were pulse-electrodeposited on conducting glass substrates with and without the addition of phosphotungstic acid. X-ray diffraction studies indicated the formation of single phase cubic ZnSe. Addition of phosphotungstic acid resulted in films with nanocrystallites. The band gap of the films was found to increase due to addition of phosphotungstic acid. The films had a crystallite size of the order of 15nm and a surface roughness of 1.8nm. Laser Raman studies exhibited the LO phonon peaks of ZnSe. The films were found to possess a slight excess of Se as evident from the energy dispersive X-ray analysis measurements.     

Photoacoustic studies on optical and thermal properties of p‐type and n‐type nanostructured porous silicon for (100) and (111) orientations

Nanostructured p‐type and n‐type porous silicon samples were prepared for (100) and (111) orientations and a systematic study is carried out on the effects of orientations, dopant type (boron and phosphorous), current density (20 and 30mA/cm²) and etching time on the formation, optical and thermal properties by photoacoustic spectroscopy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Grafted Polymeric Microspheres: A Synthetic Approach to Structurally Well-Defined Brush Polymers

Abstract

A simple method for the surface grafting of crosslinked polystyrene latex particles of narrow size distribution as core is described. Amino groups were generated on the surface of these microspheres by a two-step process of nitration and subsequent reduction. Polyethylene glycol chain of desired molecular weight was covalently linked to the surface amino group using diiso-cyanate-coupling reaction. The method is appropriate for designing brush polymers.

     

Modulating Photochemical Properties to Enhance the Stability of Electronically Dimmable Eye Protection Devices†

The study evaluates compatibility of stabilizers with dye doped liquid crystal (LC) scaffolds that are used in electronically dimmable materials. The photodegradation of the materials was investigated and suitable stabilizers were evaluated to slow the degradation process. Various types of benzotriazole-based stabilizers were evaluated for stabilizing the liquid crystals. Based on spin trapping experiments, radicals generated upon UV exposure is likely responsible for the degradation of the system. The radical generation is competitively inhibited by the addition of stabilizers.