Thermal annealing effect on the structural and optical properties of synthesized CdSe nanoparticles has been elucidated and applied on the performance improvement of bulk hetero-junction solar cell. Improvement in crystallinity and cell stabilization of as-synthesized CdSe nanoparticles could be achieved by controlling the annealing parameters. Synthesized and annealed CdSe nanoparticles were characterized by TEM, XRD, XPS, Raman and PL measurements. XRD analysis exhibited annealing-induced phase transition in the nanocrystalline CdSe from cubic Zinc Blende to hexagonal Wurtzite structure. After annealing, the intensity of PL emission peak was substantially increased, and the solar cell with optimized active layer showed enhancement in power conversion efficiency. Post-annealing process parameters for solar cell fabrication were developed based on the studies of thermal annealing effect on CdSe nanoparticles.
Anodic aluminum oxide (AAO) nano-templates were prepared using the Al/Si substrates with the thickness of the aluminum films of about 500 nm. The pores of various sizes and depths were fabricated electrochemically through anodic oxidation. The optimum morphological structure for large area InGaN LED applications was formed by adjusting the applied potential, temperature, types of acid solution and their concentration. Scanning electron microscopy (SEM) investigations showed that hexagonal-close-packed nanopore arrays have smooth wall morphologies and well-defined diameters corresponding to the diameter of the applied template.
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