الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
The properties of ZnO thin films prepared using sol-gel technique were controlled by (1) Centrifuge speed and time. (2) Annealing process. By increasing centrifuge speed to 15000 rpm for 10 min, ZnO particle size in the range from 86-100 nm was obtained. The heat treatment process improves the crystallinity of the particles, also it improves the adhesion between the ZnO and the substrate.
ZnO thin films were prepared electrochemically from aqueous solutions containing Zn(NOs)2 and introducing oxygen bubbles before the deposition process. The grain size of the prepared films decreased from about 1 um without introducing the oxygen bubbles to about 100 nm after the incorporation of the oxygen bubbles. This behavior may be attributed to oxygen which helps in transfer the zinc ions into zinc oxide. The solutions which had 0.02M zinc nitrate concentration and saturated with oxygen gas before starting the electrodeposition process showed a high transmittance value than those prepared without using oxygen bubbles. By using the electrodeposition technique, the annealing process has no significant effects on the electrodeposition films.,
The application of natural dye yields relatively good open circuit voltage compared with the N3 dye while the current density is still low for both natural and N3 dyes.
The device output parameters indicated that, the efficient cells were obtained under the following conditions:
1 - The use of propylene carbonate as electrolyte solvent 2- The addition of the 4-tert butylepyridine to the electrolyte solvent.
In order to improve the cell stability we need to:-
1- Use better sealing materials to prevent the evaporation of electrolyte
2- Replace the liquid electrolyte with a solid one.