Nanophotonics in Solar Cells

Nanophotonics is the study of how light interacts with light, on the nanoscale scale. It is an exciting branch of electronics, photonics, optics, and nanotechnology, devoted to achieving optical and electronic properties at optical frequencies. It uses techniques such as acoustic waveguides, coherent light, optical simulation, optical lasers, nanoscience methods, and various scientific approaches.

Light has many wavelengths. By using nanophotonics, one can exploit the wave nature of light to create devices that use light as input, rather than electrical power. The best known nanophotonics devices are iris lights, which use light to project an image on a transparent surface. Other uses include in displays, photography, telecommunications, biomedical science, military applications, etc. Nanophotonics enables one to control the total wavelengths of light that enter a device.

One of the unique characteristics of nanophotonics is that it produces the best results when combined with other technologies. The techniques need to be carefully studied, before applying it to achieve desired results. For example, one needs to combine the technique with laser light sources, such as LED (light emitting diode) technology, or xenon flash lamps. Another must be achieved, is for the generation of a strong and uniform transmission throughout the entire device, without any loss of optical properties at nanoscale levels. Thus, we have a set of goals for developing nanophotonics devices.

nanophotonics devices can be used to fabricate integrated circuits, which use light as input, rather than electrical power. This could enable the development of solar cells, which would in effect store energy that can then be used for powering the device during the day. In order to fabricate these nanophotonic integrated circuits, we need to develop methods for producing nanophotonics devices that do not alter the optical properties of materials used for building the circuit. This could be accomplished by means of surface plasmon resonance, wherein the surface of a semiconductor material is used to create the optical current.

We could use this method to produce, for instance, silver nanoparticles. These silver nameplates have the ability to detect laser light and change their alignment when stimulated by light of longer wavelengths. When this alignment is changed, the nameplates change their own optical properties, thus enabling them to focus on longer wavelengths, such as the ones needed to produce the electricity that power solar cells.

Silver nanoparticles can absorb energy in the form of electromagnetic radiation, which in turn excites atoms with the strength of x-rays. The excitation of the atoms produces excess electrons, which in turn produce photons. The number of photons produced by the electrons is proportional to the number of atoms that were excited. By using electrons from gold nanoparticles, we can use these gold nanoparticles to focus light in a way that alters its optical properties, which in turn changes the properties of materials used for making nanophotonics devices.