Tiny high-performance solar cells turn power generation sideways

University of Wisconsin—Madison engineers have created high-performance, micro-scale solar cells that outshine comparable devices in key performance measures. The miniature solar panels could power myriad personal devices — wearable medical sensors, smartwatches, even autofocusing contact lenses.

Large, rooftop photovoltaic arrays generate electricity from charges moving vertically. The new, small cells, capture current from charges moving side-to-side, or laterally. And they generate significantly more energy than other sideways solar systems. New-generation lateral solar cells promise to be the next big thing for compact devices because arranging electrodes horizontally allows engineers to sidestep a traditional solar cell fabrication process: the arduous task of perfectly aligning multiple layers of the cell’s material atop one another.

Top-down photovoltaic cells are made up of two electrodes surrounding a semiconducting material like slices of bread around the meat in a sandwich. When light hits the top slice, charge travels through the filling to the bottom layer and creates electric current. In the top-down arrangement, one layer needs to do two jobs: It must let in light and transmit charge. Therefore, the material for one electrode in a typical solar cell must be not only highly transparent, but also electrically conductive. And very few substances perform both tasks well.

Read more at University of Wisconsin—Madison

Image Credit: University of Wisconsin—Madison

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