Electroplating of CdTe thin films from cadmium sulphate precursor and comparison of layers grown by 3-electrode and 2-electrode systems

Electrodeposition of CdTe thin films was carried out from the late 1970s using the cadmium sulphate precursor. The solar energy group at Sheffield Hallam University has carried out a comprehensive study of CdTe thin films electroplated using cadmium sulfate, cadmium nitrate and cadmium chloride precursors, in order to select the best electrolyte. Some of these results have been published elsewhere, and this manuscript presents the summary of the results obtained on CdTe layers grown from cadmium sulphate precursor. In addition, this research program has been exploring the ways of eliminating the reference electrode, since this is a possible source of detrimental impurities, such as K+ and Ag+ for CdS/CdTe solar cells. This paper compares the results obtained from CdTe layers grown by three-electrode (3E) and two-electrode (2E) systems for their material properties and performance in CdS/CdTe devices. Thin films were characterized using a wide range of analytical techniques for their structural, morphological, optical and electrical properties. These layers have also been used in device structures; glass/FTO/CdS/CdTe/Au and CdTe from both methods have produced solar cells to date with efficiencies in the region of 5%–13%. Comprehensive work carried out to date produced comparable and superior devices fabricated from materials grown using 2E system

Bifunctional nanoparticles for SERS monitoring and magnetic intervention of assembly and enzyme cutting of DNAs

National Science Foundation [CHE 0848701, CMMI 1100736]; National Natural Science Foundation of China [21036004]; DOEThe ability to harness the nanoscale structural properties is essential for the exploration of functional properties of nanomaterials. This report demonstrates a novel strategy exploring bifunctional nanoparticles for spectroscopic detection and magnetic intervention of DNA assembly, disassembly, and enzyme cutting processes in a solution phase. In contrast to existing single-function based approaches, this strategy exploits magnetic MnZn ferrite nanoparticles decorated with gold or silver on the surface to retain adequate magnetization while producing sufficient plasmonic resonance features to impart surface-enhanced Raman scattering (SERS) functions. The decoration of MnZn ferrite nanoparticles with Au or Ag (MZF/Au or MZF/Ag) was achieved by thermally activated deposition of Au or Ag atoms/nanoparticles on MZF nanoparticles. Upon interparticle double-stranded DNA linkage of the MZF/Au (or MZF/Ag) nanoparticles with gold nanoparticles labeled with a Raman reporter, the resulting interparticle "hot spots" are shown to enable real time SERS monitoring of the DNA assembly, disassembly, or enzyme cutting processes, where the magnetic component provides an effective means for intervention of the biomolecular processes in the solution. The unique bifunctional combination of the SERS "hot spots" and the magnetic separation capability serves as the first example of bifunctional nanoprobes for biomolecular recognition and intervention