Effects of diethanolamine on sol-gel-processed Cu2ZnSnS4 photovoltaic absorber thin films

As a promising solar absorber, the Cu2ZnSnS4 compound has been popular recently for the production of green and economical thin-film solar cells owing to the abundancy and non-toxicity of all the constituents. In this study, we have produced Cu2ZnSnS4 films via the sal-gel technique. As a stabilizer, the effects of the diethanolamine on the properties of the films were investigated. The amount of diethanolamine significantly affected the crystal structure, crystallite sizes and phase purity of the films. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of phase-pure CZTS films. It was found that the film produced by using 2 ml of diethanolamine in sol exhibited pure CZTS phase, compact and dense morphology and enhanced photo-sensitivity. Light on/off current ratio of the n-Si/Cu2ZnSnS4 junction was found to be 47 under 100 mW/cm(2) of illumination. Electrical activation energies of the films were investigated and the variations were attributed to delocalized phonon states generating from the presence of other phases and lattice defects. (C) 2013 Elsevier Ltd. All rights reserved.