The research into a new type of tiny solar cell has come from technologists working at the University of Wisconsin-Madison. Although solar cells have advanced in recent years, their ability to capture sufficient energy for personal electronics has been hampered by size.
With what represents a technological leap forward, the university team have successfully developed high-performance, micro-scale lateral solar cells. To achieve this, the research group fashioned cells that include a side-by-side array of miniature electrodes on top of transparent glass. The electrodes are densely packed together so to avoid loss of energy.
The use of the glass sheet is the main innovation and the one that ensures the cells can generate sufficient power. The glass sheet separates the light-harvesting and charge-conducting functions.
Kevin ODonovan (@Kevin_ODonovan): “Very cool #innovation.. @UWMadison – Tiny high-performance #solar cells for personal #wearables.”
In trials, the solar cells achieve a conversion efficiency of 5.2 percent. While this may not seem very high it is far higher when compared to 1.8 percent for other lateral cell designs. With other designs, a large proportion of the energy is wasted because the energy is mismatched. The energy conversion is also sufficient to power the types of consumer electronics being developed.
Discussing the concept further, in an interview with Smart 2.0, lead researcher Professor Hongrui Jiang said: “From a fabrication point of view, it is always going to be easier to make side-by-side structures. Top-down structures need to be made in multiple steps and then aligned, which is very challenging at small scales. We easily beat all of the other lateral structures.”
The new cells have the potential to be used for wearable medical sensors, smartwatches, and innovative technology like auto-focusing contact lenses. In terms of future developments, it is hoped to increase the efficiency further by using alternative materials to improve conductivity.
The research has been reported to the journal Advanced Materials Technologies. The research paper is titled “Lateral Dye-Sensitized Microscale Solar Cells via Femtosecond Laser Patterning.”
