Three precursor concentrations were used for synthesizing zinc oxide nanoparticules by sol-gel via spin-coating method. The final products were synthesized at calcination temperatures of 550 degrees C during 2 h. X-ray diffraction (XRD) analysis showed that ZnO thin films were preferentially oriented along the (002) c-axis direction perpendicular to the substrate surface and had crystalline structure with a hexagonal wurtzite phase. EDX micro-analysis and morphological investigations using SEM indicated respectively that the products consist of zinc (Zn) and oxygen (0) elements and the stoichiometric atomic ratio of Zn:O congruent to 1:1, and surface of nanoparticles is homogeneous. Comparing the XRD report of three samples, it has been concluded that samples prepared at 0.75M condition give high intensity of fine peaks and better improved properties with potential applications as transparent electrodes in optoelectronic devices such as solar cells. Therefore, this deposition condition can be used for further deposition condition for reproductivity in other research laboratories.