Leightweight and flexible organic solar cells are being manufactured economically due to low material costs and efficient production technologies associated with them. The processes such as light absorption and excitation of electrons to a higher energy level and generation of highly mobile charge carriers are achieved by mixing two organic semiconductors. An organic solar cell is composed of a carrier substrate and a photoactive layer embedded between a transparent and a reflective electrode. Organic solar cells can attain the same efficiency as inorganic solar cells by optimizing one semiconductor component. The vacuum coating processes for manufacturing organic solar cells based on small molecules is identified. Continuous reel-to-reel production method for organic solar cells is preferred as high production volumes are achievable due to the attainable high transport speeds and the large web widths.