Bates College biotechnology program

Solar Cell Technology

The Office of Energy Efficiency and Renewable Energy (EERE) leads public research in innovative solar power technologies. Photovoltaic arrays, or PV for short, harness the sun?s power and turn it into electricity. When the sun shines onto a solar panel, photons are absorbed by the cells in the panel, which creates an electric field across the layers. Photovoltaic arrays must be mounted on a stable, durable structure that tilts the PV array at a fixed angle determined by the local latitude. To obtain the highest annual energy output, modules in the northern hemisphere are pointed due south and inclined at an angle equal to the local latitude. Alternatively, automatic mechanisms may be installed to move panels to track the sun across the sky, which provides more energy and a higher return on investment (ROI). Inverters are used to convert the direct current (DC) electricity generated by solar photovoltaic modules into alternating current (AC). Finally, large batteries allow for the storage of solar photovoltaic energy when bad weather blocks sunlight from reaching the photovoltaic panels.

Organic PV, or OPV, cells are composed of carbon-rich polymers and can be tailored to enhance a specific function of the cell, such as sensitivity to a certain type of light. This technology has the theoretical potential to provide electricity at a lower cost than silicon or thin-film technologies. Concentration PV, also known as CPV, focuses sunlight onto a solar cell by using a mirror or lens. By focusing sunlight onto a small area, less PV material is required. This technology uses mirrors to reflect and concentrate sunlight onto receivers that collect solar energy and convert it to heat, which can then be used to produce electricity.