In 1972, scientists discovered that chlorophyll could absorb sunlight and transfer energy into electrochemical cells. This discovery eventually led to the use of photosensitizers as sunlight-harvesting materials in solar cells, mainly through the use of photosensitizer dyes. Dye Sensitized Solar cells utilize these photosensitizer dyes to absorb photons from solar light and transfer energy rich electrons to the neighboring semiconductor material to generate electric energy output. These dyes act as dopants to semiconductor surfaces which allows for the transfer of light energy from the photosensitizer to electronic energy within the semiconductor. These photosensitizers are not limited to dyes. They may take the form of any photosensitizing structure, dependent on the semiconductor material to which they are attached.