Researchers at Sandia National Laboratories are pioneering solar photovoltaic (PV) technologies that are cheaper to produce and easier to install than traditional grid power and capable of producing clean, safe, and reliable electricity. These innovations can help accelerate the growth of PV as a mainstream power source in the United States and globally. One such innovation under development at Sandia is microsystems enabled photovoltaics (MEPV). MEPV concepts use microdesign and microfabrication techniques to produce miniaturized solar cells that are released into a solution similar to printing ink. This solution is then placed or ‘printed’ onto a low-cost substrate with embedded contacts and microlenses for focusing sunlight onto the cells. Sandia’s approach uses cells that are tiny in both thickness and lateral dimensions – as small as 14 microns thick and 250 microns wide. The thinness of the cells reduces material costs while enhancing cell performance by improving carrier collection and potentially achieving higher open circuit voltages. Sandia’s microsystems enabled PV advances combine mature technology and tools currently used in microsystem production with groundbreaking advances in photovoltaic cell design, decreasing production and system costs while improving energy conversion efficiency. The technology has potential applications in buildings, houses, clothing, portable electronics, vehicles, and other contoured structures.
Watch Sandia researcher Vipin Gupta discussing MEPV at the 2014 TEDxABQ.
Flexible photovoltaic module draped over a probe tip.
Flexible photovoltaic devices consist of microscale photovoltaic cells that convert artificial or natural light into electricity. Like Georges Seurat’s pointillist paintings, the device can holds thousands of interconnected photovoltaic dots that are as small as the period at the end of this sentence. With such small components, the device can be bent or contoured to fit onto virtually any surface without cracking or breaking. This flexibility enables the device to be patterned aesthetically or blended inconspicuouslyinto buildings, vehicles, consumer electronics, and even the human body — providing electricity without human thought or attention. Like rigid formats, flexible photovoltaic devices generate electricity through the photovoltaic effect. When light shines on the microscale silicon dots, electrons are excited, flow into the underlying microwire circuit, and are collected at the terminals. The generated electricity can be used immediately to power things or stored in batteries for later use. Either way, the powering of almost anything becomes as simple as exposing it to light.
Flexible MEPV Publications
- Jose L. Cruz-Campa, Gregory N. Nielson, Murat Okandan, Paul J. Resnick, Carlos A. Sanchez, Janet Nguyen, Benjamin B. Yang, Alice C. Kilgo, Christine Ford, Jeff S. Nelson (2013). 1000 V/cm2. These modules are also ultra-flexible with tight bending radii down to 1 mm. The module is composed of hundreds of back contact microcells with thicknesses of approximately 20 μm and diameters between 500-720 μm. The cells are interconnected to a flexible circuit through solder contacts. We studied the characteristics of several mini-modules through optical inspection, evaluation of quantum efficiency, measurement of current-voltage curves, and temperature dependence. Major efficiency losses are caused by missing cells or non-interconnected cells. Secondarily, damage incurred during separation of 500 μm cells from the substrate caused material detachment. The detachment induced higher recombination and low performance. Modules made with the larger cells (720 μm) performed better due to having no missing cells, no material detachment and optimized AR coatings. The conversion efficiency of the best mini module was 13.75% with a total Voc = 7.9 V. ,(Downloaded 248 times)">Ultra-thin single crystal silicon modules capable of 450 W/kg and bending radii <1mm: fabrication and characterization ( 427.91 kB)
- J.L. Cruz-Campa, G.N. Nielson, M. Okandan, P.J. Resnick, C.A. Sánchez, V.P. Gupta, J.S. Nelson (2012). Ultrathin and Flexible Single Crystal Silicon Mini-Modules ( 590.21 kB)
- Jose L. Cruz-Campa, Gregory N. Nielson, Paul J. Resnick, Carlos A. Sanchez, Peggy J. Clews, Murat Okandan, Vipin Gupta (2011). Ultrathin Flexible Crytalline Silicon: Microsystems Enabled Photovoltaics ( 408.32 kB)
Flexible photovoltaic module with the distance between curved peaks being measured. The ruler unit is in centimeters.
Mechanical model of a flexible photovoltaic module. Each individual cell is hexagonal in shape.
Four photovoltaic modules on a flexible substrate prior to cutting.
LED device powered by flexible photovoltaic module. The module is made of 73 individual, microscale, crystalline silicon cells.
Partnership Opportunity for Microscale Photovoltaic (PV) Technologies
SNL is seeking a collaborative partnership with an industrial partner who has experience in the design, development, and manufacturing of semiconductor devices or solar technologies. The objective of this partnership would be the joint development and demonstration of a full scale prototype, moving the technology from Technology Readiness Level (TRL) 3 to TRL 6 or 7, as defined by the U.S. Department of Energy. Collaborators will work with SNL on the continued development and testing of microscale PV technologies and will provide a clear path to commercialization/deployment of the technology through refined product design, optimization for manufacturing, and Quality Assurance. Qualified partners will contribute resources, funds including funds for Sandia specialists (as needed), and in-kind support in the form of staff and facilities capable of handling, processing, and packaging microscale PV cells. Qualified partners will have the option to obtain, up to and including, an exclusive license to the intellectual property for reasonable compensation as part of the agreement. View Solicitation