This technology can be applied to converting sunlight into electricity.
Conventional photovoltaic cells rely on semiconductor band gaps to convert incoming photons into electrical energy. However, these semiconductors can only utilize a portion of the solar spectrum, consequently requiring expensive multi-junction cells are needed to improve efficiency. Furthermore, because they rely on indirect transitions, traditional cells have a relatively bulky thickness. The new metallic PV device can be made from potentially cheaper materials, it uses much thinner construction, and could be tuned to absorb additional portions of the solar spectrum. These advantages could reduce the overall cost of solar energy or lead to novel ultralight applications.
This photovoltaic device layers a semiconductor over a metallic absorber to form a Schottky barrier. The metallic absorber collects photons from direct transitions to create charges that flow into the semiconductor. Electrical contacts on the semiconductor carry the current out of the device. The bandwidth of absorbed photons can be tuned by selecting the appropriate semiconductor and metal combination to control the height of the Schottky barrier. This device has the potential of being significantly cheaper than conventional multi-junction photovoltaic cells because this device is not limited to group III-V semiconductors, which are
typically used in multi-junction photovoltaic cells, but can also use much smaller quantities of cheaper group II-VI
and group IV semiconductors. Furthermore, multiple semiconductor/metal layers can be stacked together to create different Schottky barriers that have different bandwidths, which can increase the efficiency. This device can also be used in conjunction with conventional single-junction photovoltaic cells to absorb a portion of the solar spectrum that the conventional cells cannot utilize.
- Can be adapted to absorb a wide range of photon wavelengths
- May be lower cost than existing photovoltaic devices
- Thinner size enables ultralight packaging for novel applications
- Can be used in conjunction with conventional photovoltaic devices to improve efficiency