Solar technology has become more popular in America to power homes with greater efficiency and lower costs. According to the Solar Energy Industries Association (SEIA), the United States has an estimated 97.2 gigawatts of solar power. This is approximately the amount of energy required to power 18 million homes. It also accounts for over 3% of U.S electricity.
What about small-scale applications? Solar power can bring important benefits that are not related to the environmental benefits of large-scale solar energy.
English muffins and sponges are good, thanks to the holes. They wouldn’t be able to bend into tiny crevices or soak up enough butter and jam without holes.
Researchers at the University of Chicago have found that holes can be used to improve technology, such as medical devices, in a new study. The paper was published in Nature Materials. It describes a new method of making a solar cell by drilling holes into the top layer. This makes it porous.
This innovation could be used to create a less-invasive pacemaker or other similar medical devices. The small light source could be used to reduce the size and weight of the current pacemakers.
Aleksander Prominski was the first to sign the paper.
Light work
Prominski is part of the University of Chicago Chemist Bozhi Tian’s lab, which specializes in creating connections between biological tissue and artificial material–such as wires that modulate brain signals or surfaces to support medical implants.
They are interested in making devices that can be powered with light. This technology is most commonly used in the form of solar cells. However, they can be powered by any light source, even artificial ones. These devices, also known as photoelectrochemical cells implanted inside the body, can be powered by a tiny optical fibre.
Two layers are required for solar cells. This can be done by either combining silicon with another material like gold or mixing different types of atoms into each layer.
The Tian lab at UChicago discovered they could make a solar cell from pure silicon by making one layer porous like a sponge.
The resultant soft, flexible cell is less than 5 microns, roughly the same size as a single red cell. The implant can be paired with optic fibre. This can reduce the overall size by up to 5 microns, making it easier for the body and less likely to cause side effects.
The porous solar cell offers many advantages over traditional solar cell manufacturing methods. It streamlines the production process and maintains the product’s efficacy.
Prominski stated that they can be made in minutes and don’t require toxic gases or high temperatures.
Jiuyun Shi, the study co-author, added: “When they measured them we saw that the photocurrent was really strong–two orders higher than our earlier designs.”
To increase the material’s potential to stimulate the heart or nerve cells, oxygen plasma is used to treat the surface layer. Tian said this step is counterintuitive to chemists because silicon oxide works most often as an insulator, and “you don’t want the photoelectrochemical effects to be impeded” by insulating materials. In this case, however, oxidization helps by making the silicon material hydrophilic–attracted to water–which boosts the signal to biological tissues. Pengju Li, another study’s co-author, stated that you could enhance the device’s properties by adding a thin layer of metal oxide.
Scientists can make all components biodegradable to be used in short-term cardiac procedures. The parts will naturally degrade after a few months instead of needing to be removed by another surgeon. This innovative approach could also prove useful in a procedure called cardiac rhythm therapy, which attempts to correct arrhythmias in which the hearts’ left and right chambers do not beat simultaneously. The devices could be placed in several areas of the heart to increase coverage.
Prominski is also enthusiastic about potential applications for nerve stimulation. He said he could see implanting such devices in patients with chronic nerve degeneration, such as in their wrists or hands, to provide pain relief.
This innovative method of making solar cells may also be useful for non-medical purposes such as sustainable energy and other non-medical uses. These solar cells work best in liquid environments, so UChicago scientists believe they could be used for applications like solar fuels and artificial leaves.
