Tiny High-performance Solar Cells Turn Power Generation Sideways
August 4, 2016 | University of Wisconsin-MadisonEstimated reading time: 3 minutes
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, described today (Aug. 3, 2016) in the journal Advanced Materials Technologies, 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.
“From a fabrication point of view, it is always going to be easier to make side-by-side structures,” says Hongrui Jiang, a UW–Madison professor of electrical and computer engineering and corresponding author on the paper. “Top-down structures need to be made in multiple steps and then aligned, which is very challenging at small scales.”
Lateral solar cells also offer engineers greater flexibility in materials selection.
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.
Instead of building its solar cell sandwich one layer at a time, Jiang’s group created a densely packed, side-by-side array of miniature electrodes on top of transparent glass. The resulting structure — akin to an entire loaf of bread’s worth of solar-cell sandwiches standing up sideways on a clear plate — separates light-harvesting and charge-conducting functions between the two components.
Generally, synthesizing such sideways sandwiches is no simple matter. Other approaches that rely on complicated internal nanowires or expensive materials called perovskites fall short on multiple measures of solar cell quality.
“We easily beat all of the other lateral structures,” says Jiang.
Existing top-of the-line lateral new-generation solar cells convert merely 1.8 percent of incoming light into useful electricity. Jiang’s group nearly tripled that measure, achieving up to 5.2 percent efficiency.
“In other structures, a lot of volume goes wasted because there are no electrodes or the electrodes are mismatched,” says Jiang. “The technology we developed allows us to make very compact lateral structures that take advantage of the full volume.”
Packing so many electrodes into such a small volume boosted the devices’ “fill factors,” a metric related to the maximum attainable power, voltage and current. The structures realized fill factors up to 0.6 — more than twice the demonstrated maximum for other lateral new-generation solar cells.
Jiang and colleagues are working to make their solar cells even smaller and more efficient by exploring materials that further optimize transparency and conductivity. Ultimately they plan to develop a small-scale, flexible solar cell that could provide power to an electrically tunable contact lens.
Other authors on the paper included Xi Zhang, Yinggang Huang, Hao Bian, Hewei Liu, and Xuezhen Huang. The National Institutes of Health provided funding for the research.
Suggested Items
Groundbreaking Ceremony Marks the Beginning of a New Era for Newccess Industrial; The Construction of the MINGXIN Building
04/12/2024 | Newccess IndustrialOn a clear and sunny day in March, the groundbreaking ceremony for the MINGXIN Building took place in Shenzhen, China. This moment marked the official commencement of construction for a project that will reshape the semiconductor materials industry.
The Need for a Holistic Global Sustainability Standard
04/10/2024 | Michael Ford, Aegis SoftwareNo one can deny that the resources of our fragile planet are finite. The environment seems like a third party, subject to constant degradation. We’re acutely aware of the effects of pollution on our climate, and despite our “throw-away” culture, recycling and recovery of materials has remained relatively expensive, even as we use more energy just to survive.
iNEMI Publishes Four Roadmap Topics
04/04/2024 | iNEMIThe International Electronics Manufacturing Initiative (iNEMI) announces the availability of the first roadmap topics in the new iNEMI Roadmap format. Printed circuit boards, sustainable electronics, smart manufacturing, and mmWave materials and test are now available online.
Insulectro’s 'Storekeepers' Extend Their Welcome to Technology Village at IPC APEX EXPO
04/03/2024 | InsulectroInsulectro, the largest distributor of materials for use in the manufacture of PCBs and printed electronics, welcomes attendees to its TECHNOLOGY VILLAGE during this year’s IPC APEX EXPO at the Anaheim Convention Center, April 9-11, 2024.
Checking In With ICAPE Group
04/03/2024 | Nolan Johnson, I-Connect007ICAPE Group’s field application engineer Erik Pederson drills down on sustainability, supply chain resiliency, and what value engineering really looks like in this exclusive interview. Founded in 1999, European-based ICAPE Group provides 21 million printed circuit boards and over six million technical parts to manufacturers every month. With 30 PCB manufacturing partners globally and 50 partners providing a wide array of technical parts, ICAPE Group has operations in China, Taiwan, Thailand, South Korea, Vietnam, South Africa, Europe, Mexico, and the United States. The company also focuses on the value proposition for its customers.