Influences of Aluminum Concentration to the Characteristics of ZnO Electron Transport Layer and its Hybrid Polymer Solar Cell

摘要

The preparation and characteristics of Aluminum doped (AZO) thin films by sol-gel process from precursor solution composed of zinc acetate dihydrate and aluminum chloride with various molar percentage have been investigated. Their optical and electrical characteristics were studied by optical UV-Vis spectroscopy and Hall effect measurements, which indicate that the optical transparency and charge carrier density increase with the addition of small concentration of Al (0.8 mol%) but decrease with further addition. These characteristics is consistent with the crystal structure and nano-morphology characterization results, performed by means of XRD spectroscopy and Atomic Force, respectively, which show the increase of the proportion of the preferred crystal orientation (002) and reduction of surface roughness at small Al concentration. The effect of Aluminum concentration on photovoltaic characteristics in hybrid solar cells based on P3HT:PCBM blend polymer by utilizing this AZO layer has also been studied. The solar cell performance improves by using this AZO layer with small Al concentration of about 0.8 mol% as its electron transport layer.