Zinc sulfide is a wide band gap semiconductor with high refractive index and hence a promising material for antireflection coating over commercial silicon solar cells. In the present work, attempts have been made to improve the rate of deposition, uniformity of deposited film, stoichiometry, refractive index and the percentage of reflection, respectively, by proper optimization of molar percentage of different CBD ZnS bath chemical constituents and deposition conditions. High values of the rate of film deposition (19.6 Angstrom), film uniformity (S.D. < 1.8) and refractive index (2.35) along with a low percentage of average reflection (0.655) are achieved with proper optimization of ZnS bath. We have successfully fabricated 13.8% efficient large area (103 turn x 103 mm) mono-crystalline silicon solar cells with CBD ZnS antireflection coating. (C) 2004 Elsevier B.V. All rights reserved.