It is used in constructing integrated photovoltaic power systems and as a semi-transparent photovoltaic glazing material that can be laminated into windows. Some commercial uses use rigid thin-film solar panels (sandwiched between two glass panes) in some of the world's largest photovoltaic. Many photovoltaic materials are manufactured using different deposition methods on various substrates. Therefore, thin-film solar cells are generally classified. Thin film technology has always been cheaper but less efficient than conventional c-Si technology. However, it has improved significantly over the years. Multiple techniques have been used to increase the amount of light entering the cell and reduce the amount that escapes without absorption.