Reflectance calculation for various single-, double-and triple-layer Antireflection coatings (ARCs) on silicon substrate are presented. A calculation program is developed to determine the optimum thickness and the refractive index of each layer at a single wavelength for optoelectronic applications and through the visible spectrum for photovoltaic applications. Ta2O5, ZnS, Al2O3 single layer, MgF2/Zns double layer and MgF2/Al2O3/ZnS triple layer ARC systems are deposited on silicon substrate using electron beam and thermal evaporation as deposition techniques. The reflectance as a function of the wavelength of AR coating systems on silicon substrate is measured, All curves show good accordance between the theoretical and the experimental reflectance. As application in the photovoltaic field, a ZnS single-layer AR coating is evaporated on concentrator silicon solar cells. Spectral response and current-voltage characteristics are measured before and after ZnS ARC deposition to estimate the improvement of the cell performances. Short-circuit current and cell efficiency are increased by about 31% and 29.4%, respectively.