Zinc oxide and doping effects of Cu on its structural, morphological, optical, and surface wettability properties and the consequent influence on photoelectrochemical solar cell performance has been reviewed. Cu dopant in the doping solution is varied in the range of 1 to 5 at.% which significantly affected the properties of ZnO. Slight changes in the lattice parameters of the Cu-doped zinc oxide (CZO) electrodes were reported, due to the successful substitution of Zn 2+ by Cu 2+ and also enhancement in crystallinity of the films at 3 at.% Cu due to reduction in crystallographic defects in the film. Surface morphologies were reported with densely grown nanorods over the varied range of Cu, with 3 at.% having the densest microstructures with average diameter approximately 125 nm. A review of optical properties indicated significant enhancement in absorption edge of approximately 60 nm into the visible band for the nanorods with 3 at.% Cu content due to light scattering. Optical energy band-gaps decrease from 3.03 to 2.70 eV with Cu doping. Surface wettability was adjudged hydrophilic for all the films, implying high porosity and water contact angles depended on Cu content. Photoelectrochemical cell performance indicated an n-type photoactivity in sodium sulfate (Na 2 SO 4) electrolyte, which motivates to check its feasibility in solar cell applications.

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Herein, a forced convection solar fish dryer is designed, constructed and characterized to yield a better main of drying fish. The designed dryer incorporated a heat storage unit which complimented the drying rate of the product during off sunshine hours. The device was characterized during raining and dry seasons and results clearly indicated the influence of seasonal variation on the performance of the device. Average hourly variation of the dryer and ambient temperatures measured on the selected days of the different months of measurement during the two seasons, clearly indicated that temperatures were significantly enhanced by the device. This was due to the high ability of the designed solar collector to trap large amount of long waves. Maximum dryer and ambient temperatures during raining season were measured to be (58.9±2) oC and (40±2) oC whereas, (73.5±1.3) oC and (45±1.8) oC respectively, were measured during the dry season. Average daily moisture loss from the drying fish was notably high, especially during dry season which was due to the high dryer temperatures and decrease in atmospheric humidity. The efficiency of the solar dryer was estimated to be 76 %. The fishes with initial moisture content of 87 % was dried to 13 %. This moisture content is in range with the United Nations Economic Commission for Europe (UNECE) Standard DDP-19 concerning the marketing and commercial quality control of dried fish.