Success Stories
A PV solar cell is a specialized semiconductor diode that converts visible light into a direct current. The PV cell allows solar light to be absorbed efficiently by a material and then converted into charge carriers that generate an electrical current, known as a photocurrent.
(Research physicists, (left to right) Domenico de Ceglia, Neset Akozbek, Dr. Michael Scalora and Maria Antonietta Vincenti, assess the solar cell transmission, reflection, absorption properties using a tunable laser source at the Charles M. Bowden labortories.)
Solar Cell Technology
Scientists within the Weapons Development and Integration Directorate received a 2015 patent for the development of a revolutionary photovoltaic solar cell designed to convert light energy into electrical energy.
“Photonic Bandgap Solar Cells”, U.S. patent number 8,993,874, reveals a new kind of photovoltaic solar cell that offers a dramatically reduced size and cost compared to current solar cells. A PV solar cell is a specialized semiconductor diode that converts visible light into a direct current. The PV cell allows solar light to be absorbed efficiently by a material and then converted into charge carriers that generate an electrical current, known as a photocurrent.
The next generation of solar cells has begun to address costs, materials, and flexibility problems, in addition to reducing the thickness of the PV cell. The newly-designed, multilayer stack has dramatically reduced the size of a PV cell, approximately 1,000 times thinner than that of the previous 100- 200 microns which was about the size of a grain of sand.
The invention was designed to overcome current solar panel problems such as wear out, damage, and stress introduced to the structure by heating. Damage and heating in a solar panel is produced by absorption of the high content of ultraviolent and infrared radiation from the sun. UV and IR radiation can either be reflected by the solar panel cells to avoid damage to the structure or absorbed in materials having the appropriate bandgaps to generate an electrical photocurrent.
The reduced transparency allows the layers of the PV cell to almost completely absorb incoming sunlight. A critical problem with radiation is the mismatch between the broad wavelength band available in sunlight and the narrow wavelength band associated with semiconductor energy bandgap. If light was allowed to enter the cell, this mismatch would cause a loss of power.
By using the photonic bandgap approach developed in this invention, solar cells will operate more efficiently than presently possible.
