Hybrid solar cells with ITO/AZO/ZnS/P3HT/PCBM/Ag structure were fabricated so that, in the synthesis of the ZnS layer, the successive ion layer absorption and reaction (SILAR) technique was used. At first, Al-doped ZnO (AZO) layers with different molar concentrations of Al were deposited on ITO-glass substrates, and the optimum concentration was determined to produce the maximum power conversion efficiency. The ZnS layer with different SILAR cycles was then grown on ITO/ AZO to fabricate the highly efficient solar cell. X-ray diffraction analysis confirmed the formation of pure, nanocrystalline, and cubic structure of ZnS. Optical measurements showed that the band gap of ZnS quantum dots varies in a narrow range of 3.8–4.0 eV, depending on the number of SILAR cycles. The effect of the number of cycles on the solar cell performance was investigated. The photovoltaic properties of fabricated cells under the illumination of one sun (AM 1.5, 100 mW∕cm2) have been examined. The results indicated that changing the number of SILAR cycles improves the performances of the fabricated photovoltaic cells; a high efficiency of 3.25% was observed at six cycles.
