Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Glitter-sized solar photovoltaics produce competitive results

Representative thin crystalline-silicon photovoltaic cells – these are from 14 to 20 micrometers thick and 0.25 to 1 millimeter across. (Image by Murat Okandan)
Representative thin crystalline-silicon photovoltaic cells – these are from 14 to 20 micrometers thick and 0.25 to 1 millimeter across. (Image by Murat Okandan)

Abstract:
Adventures in microsolar supported by microelectronics and MEMS techniques

Glitter-sized solar photovoltaics produce competitive results

Albuquerque, NM | Posted on December 23rd, 2009

Sandia National Laboratories scientists have developed tiny glitter-sized photovoltaic cells that could revolutionize the way solar energy is collected and used.

The tiny cells could turn a person into a walking solar battery charger if they were fastened to flexible substrates molded around unusual shapes, such as clothing.

The solar particles, fabricated of crystalline silicon, hold the potential for a variety of new applications. They are expected eventually to be less expensive and have greater efficiencies than current photovoltaic collectors that are pieced together with 6-inch- square solar wafers.

The cells are fabricated using microelectronic and microelectromechanical systems (MEMS) techniques common to today's electronic foundries.

Sandia lead investigator Greg Nielson said the research team has identified more than 20 benefits of scale for its microphotovoltaic cells. These include new applications, improved performance, potential for reduced costs and higher efficiencies.

"Eventually units could be mass-produced and wrapped around unusual shapes for building-integrated solar, tents and maybe even clothing," he said. This would make it possible for hunters, hikers or military personnel in the field to recharge batteries for phones, cameras and other electronic devices as they walk or rest.

Even better, such microengineered panels could have circuits imprinted that would help perform other functions customarily left to large-scale construction with its attendant need for field construction design and permits.

Said Sandia field engineer Vipin Gupta, "Photovoltaic modules made from these microsized cells for the rooftops of homes and warehouses could have intelligent controls, inverters and even storage built in at the chip level. Such an integrated module could greatly simplify the cumbersome design, bid, permit and grid integration process that our solar technical assistance teams see in the field all the time."

For large-scale power generation, said Sandia researcher Murat Okandan, "One of the biggest scale benefits is a significant reduction in manufacturing and installation costs compared with current PV techniques."

Part of the potential cost reduction comes about because microcells require relatively little material to form well-controlled and highly efficient devices.

From 14 to 20 micrometers thick (a human hair is approximately 70 micrometers thick), they are 10 times thinner than conventional 6-inch-by-6-inch brick-sized cells, yet perform at about the same efficiency.

100 times less silicon generates same amount of electricity

"So they use 100 times less silicon to generate the same amount of electricity," said Okandan. "Since they are much smaller and have fewer mechanical deformations for a given environment than the conventional cells, they may also be more reliable over the long term."

Another manufacturing convenience is that the cells, because they are only hundreds of micrometers in diameter, can be fabricated from commercial wafers of any size, including today's 300-millimeter (12-inch) diameter wafers and future 450-millimeter (18-inch) wafers. Further, if one cell proves defective in manufacture, the rest still can be harvested, while if a brick-sized unit goes bad, the entire wafer may be unusable. Also, brick-sized units fabricated larger than the conventional 6-inch-by-6-inch cross section to take advantage of larger wafer size would require thicker power lines to harvest the increased power, creating more cost and possibly shading the wafer. That problem does not exist with the small-cell approach and its individualized wiring.

Other unique features are available because the cells are so small. "The shade tolerance of our units to overhead obstructions is better than conventional PV panels," said Nielson, "because portions of our units not in shade will keep sending out electricity where a partially shaded conventional panel may turn off entirely."

Because flexible substrates can be easily fabricated, high-efficiency PV for ubiquitous solar power becomes more feasible, said Okandan.

A commercial move to microscale PV cells would be a dramatic change from conventional silicon PV modules composed of arrays of 6-inch-by-6-inch wafers. However, by bringing in techniques normally used in MEMS, electronics and the light-emitting diode (LED) industries (for additional work involving gallium arsenide instead of silicon), the change to small cells should be relatively straightforward, Gupta said.

Each cell is formed on silicon wafers, etched and then released inexpensively in hexagonal shapes, with electrical contacts prefabricated on each piece, by borrowing techniques from integrated circuits and MEMS.

Offering a run for their money to conventional large wafers of crystalline silicon, electricity presently can be harvested from the Sandia-created cells with 14.9 percent efficiency. Off-the-shelf commercial modules range from 13 to 20 percent efficient.

A widely used commercial tool called a pick-and-place machine — the current standard for the mass assembly of electronics — can place up to 130,000 pieces of glitter per hour at electrical contact points preestablished on the substrate; the placement takes place at cooler temperatures. The cost is approximately one-tenth of a cent per piece with the number of cells per module determined by the level of optical concentration and the size of the die, likely to be in the 10,000 to 50,000 cell per square meter range. An alternate technology, still at the lab-bench stage, involves self-assembly of the parts at even lower costs.

Solar concentrators — low-cost, prefabricated, optically efficient microlens arrays — can be placed directly over each glitter-sized cell to increase the number of photons arriving to be converted via the photovoltaic effect into electrons. The small cell size means that cheaper and more efficient short focal length microlens arrays can be fabricated for this purpose.

High-voltage output is possible directly from the modules because of the large number of cells in the array. This should reduce costs associated with wiring, due to reduced resistive losses at higher voltages.

Other possible applications for the technology include satellites and remote sensing.

The project combines expertise from Sandia's Microsystems Center; Photovoltaics and Grid Integration Group; the Materials, Devices, and Energy Technologies Group; and the National Renewable Energy Lab's Concentrating Photovoltaics Group.

Involved in the process, in addition to Nielson, Okandan and Gupta, are Jose Luis Cruz-Campa, Paul Resnick, Tammy Pluym, Peggy Clews, Carlos Sanchez, Bill Sweatt, Tony Lentine, Anton Filatov, Mike Sinclair, Mark Overberg, Jeff Nelson, Jennifer Granata, Craig Carmignani, Rick Kemp, Connie Stewart, Jonathan Wierer, George Wang, Jerry Simmons, Jason Strauch, Judith Lavin and Mark Wanlass (NREL).

The work is supported by DOE's Solar Energy Technology Program and Sandia's Laboratory Directed Research & Development program, and has been presented at four technical conferences this year.

The ability of light to produce electrons, and thus electricity, has been known for more than a hundred years.

####

About Sandia National Laboratories
Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, an autonomous Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

For more information, please click here

Contacts:
Neal Singer

(505) 845-7078

Copyright © Sandia National Laboratories

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Oxford Instruments announces Dr Kate Ross as winner of the 2018 Lee Osheroff Richardson Science Prize for North and South America February 20th, 2018

Computers aid discovery of new, inexpensive material to make LEDs with high color quality February 20th, 2018

Unconventional superconductor may be used to create quantum computers of the future: They have probably succeeded in creating a topological superconductor February 19th, 2018

Photonic chip guides single photons, even when there are bends in the road February 16th, 2018

Possible Futures

Computers aid discovery of new, inexpensive material to make LEDs with high color quality February 20th, 2018

Photonic chip guides single photons, even when there are bends in the road February 16th, 2018

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers February 15th, 2018

Rutgers-Led Innovation Could Spur Faster, Cheaper, Nano-Based Manufacturing: Scalable and cost-effective manufacturing of thin film devices February 14th, 2018

MEMS

First Capacitive Transducer with 13nm Gap July 27th, 2017

Bosch announces high-performance MEMS acceleration sensors for wearables June 27th, 2017

Smart multi-layered magnetic material acts as an electric switch: New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current March 1st, 2017

Engineers shrink microscope to dime-sized device February 17th, 2017

Self Assembly

Liquid crystal molecules form nano rings: Quantized self-assembly enables design of materials with novel properties February 7th, 2018

Particle size matters for porous building blocks: Rice University scientists find porous nanoparticles get tougher under pressure, but not when assembled December 19th, 2017

Physicists gain new insights into nanosystems with spherical confinement: Enormous potential for the targeted delivery of pharmaceutical agents and the creation of tailored nanoparticles July 27th, 2017

Oddball enzyme provides easy path to synthetic biomaterials May 17th, 2017

Sensors

Graphene on toast, anyone? Rice University scientists create patterned graphene onto food, paper, cloth, cardboard February 13th, 2018

Leti Chief Scientist Barbara De Salvo Will Help Kick Off ISSCC 2018 with Opening-Day Keynote: In Addition, Leti Scientists Will Present and Demo New Technology for Piezoelectric Energy Harvesting February 8th, 2018

Engineers develop flexible, water-repellent graphene circuits for washable electronics January 24th, 2018

Leti to Demo New Curving Technology at Photonics West that Improves Performance of Optical Components January 18th, 2018

Announcements

Oxford Instruments announces Dr Kate Ross as winner of the 2018 Lee Osheroff Richardson Science Prize for North and South America February 20th, 2018

Computers aid discovery of new, inexpensive material to make LEDs with high color quality February 20th, 2018

Unconventional superconductor may be used to create quantum computers of the future: They have probably succeeded in creating a topological superconductor February 19th, 2018

Photonic chip guides single photons, even when there are bends in the road February 16th, 2018

Military

Graphene on toast, anyone? Rice University scientists create patterned graphene onto food, paper, cloth, cardboard February 13th, 2018

Silk fibers could be high-tech ‘natural metamaterials’ January 31st, 2018

Researchers use sound waves to advance optical communication January 22nd, 2018

New Method Uses DNA, Nanoparticles and Top-Down Lithography to Make Optically Active Structures: Technique could lead to new classes of materials that can bend light, such as for those used in cloaking devices January 18th, 2018

Textiles/Clothing

Candy cane supercapacitor could enable fast charging of mobile phones August 17th, 2017

Carbodeon demonstrates NanoDiamond nickel coatings with enhanced tribological properties June 7th, 2017

New ultrafast flexible and transparent memory devices could herald new era of electronics April 1st, 2017

'Back to the Future' inspires solar nanotech-powered clothing November 15th, 2016

Aerospace/Space

Joseph N. Pelton named 2017 Lifeboat Foundation Guardian Award Winner February 1st, 2018

New research yields super-strong aluminum alloy January 25th, 2018

Nanotube fibers in a jiffy: Rice University lab makes short nanotube samples by hand to dramatically cut production time January 11th, 2018

Teachers in Space, Inc. wins Dream Project contest January 9th, 2018

Solar/Photovoltaic

A simple new approach to plastic solar cells: Osaka University researchers intelligently design new highly efficient organic solar cells based on amorphous electronic materials with potential for easy printing January 28th, 2018

Tweaking quantum dots powers-up double-pane solar windows: Engineered quantum dots could bring down the cost of solar electricity January 2nd, 2018

Record high photoconductivity for new metal-organic framework material December 15th, 2017

Inorganic-organic halide perovskites for new photovoltaic technology November 6th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project