Application of Lithium Chloride Dopant in Fabrication of CdTe Solar Cells

We report use of lithium chloride (LiCl) as a non-Cd dopant to deal with the environmental issues associated with use of traditional CdCl 2 dopant in CdTe solar cells. It has been found that, after LiCl treatment, device performance parameters including external quantum efficiency and conversion efficiency were improved considerably, being comparable to those of a counterpart treated with CdCl 2 . The optimal efficiency of 9.58% was obtained at 405°C, and V oc as high as ∼737.3 mV was obtained at 385°C. Thorough study of the properties of the CdTe film treated by LiCl by x-ray diffraction analysis, scanning electron microscopy, x-ray photoelectron spectroscopy, and secondary-ion mass spectroscopy further verified the feasibility of posttreatment with nontoxic LiCl for fabrication of CdTe photovoltaic devices. The doping level of p -type CdTe thin film was improved by lithium. This represents a nontoxic approach for fabrication of commercial CdS/CdTe thin-film solar cells with better performance.