In this work, we report on the results of using a Diamond-Like Carbon / Porous Silicon (DLC/PS) double layer as antireflection coating to enhance the performance of multicrystalline silicon photovoltaic cells. DLC layers were obtained by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. The properties of these layers were investigated in order to establish the optimum preparation conditions for solar cell applications. Then, thin films of combined porous silicon-DLC structure were fabricated for antireflection coating use. The spectral response of a solar cell based on multicrystalline silicon (mc-Si) coated with a PS layer, formed by electrochemical process was enhanced compared to a cell without porous silicon layer as emitter. Further improvements are obtained by a deposition of a thin DLC film. The results of the solar cell parameters before and after porous silicon formation and DLC coating are discussed.