How to resolve AdBlock issue? 
News
For all their promise, solar cells have frustrated scientists in one crucial regard – most are rigid. They must be deployed in stiff, often heavy, fixed panels, limiting their applications.
So researchers have been trying to get photovoltaics to loosen up. The ideal: flexible, decal-like solar panels that can be peeled off like band-aids and stuck to virtually any surface, from papers to window panes.
Now the ideal is real. Stanford researchers have succeeded in developing the world’s first peel-and-stick thin-film solar cells. The breakthrough is described in a paper in the December 20th issue of Scientific Reports.
Unlike standard thin-film solar cells, the peel-and-stick version from Stanford does not require any direct fabrication on the final carrier substrate.
This is a far more dramatic development than it may initially seem. All the challenges associated with putting solar cells on unconventional materials are avoided with the new process, vastly expanding the potential applications of solar technology.
Thin-film photovoltaic cells are traditionally fixed on rigid silicon and glass substrates, greatly limiting their uses, says Chi Hwan Lee, lead author of the paper and a PhD candidate in mechanical engineering.
And while the development of thin-film solar cells promised to inject some flexibility into the technology, explains Xiaolin Zheng, a Stanford assistant professor of mechanical engineering and senior author of the paper, scientists found that use of alternative substrates was problematic in the extreme.
“Nonconventional or ‘universal’ substrates are difficult to use for photovoltaics because they typically have irregular surfaces and they don’t do well with the thermal and chemical processing necessary to produce today’s solar cells,” Zheng observes. “We got around these problems by developing this peel-and-stick process, which gives thin-film solar cells flexibility and attachment potential we’ve never seen before, and also reduces their general cost and weight.”
Utilizing the process, Zheng continues, researchers attached their solar cells to paper, plastic and window glass among other materials.
“It’s significant that we didn’t lose any of the original cell efficiency,” Zheng said.
The new process involves a unique silicon, silicon dioxide and metal “sandwich.” First, a 300-nanometer film of nickel (Ni) is deposited on a silicon/silicon dioxide (Si/SiO2) wafer.
Thin-film solar cells are then deposited on the nickel layer utilizing standard fabrication techniques, and covered with a layer of protective polymer.
A thermal release tape is then attached to the top of the thin-film solar cells to augment their transfer off of the production wafer and onto a new substrate.
The solar cell is now ready to peel from the wafer. To remove it, the wafer is submerged in water at room temperature and the edge of the thermal release tape is peeled back slightly, allowing water to seep into and penetrate between the nickel and silicon dioxide interface. The solar cell is thus freed from the hard substrate but still attached to the thermal release tape.
Zheng and team then heat the tape and solar cell to 90°C for several seconds, then the cell can be applied to virtually any surface using double-sided tape or other adhesive. Finally, the thermal release tape is removed, leaving just the solar cell attached to the chosen substrate.
Tests have demonstrated that the peel-and-stick process reliably leaves the thin-film solar cells wholly intact and functional, Zheng said. “There’s also no waste. The silicon wafer is typically undamaged and clean after removal of the solar cells, and can be reused.”
While others have been successful in fabricating thin-film solar cells on flexible substrates before, those efforts have required modifications of existing processes or materials, noted Lee.
“The main contribution of our work is we have done so without modifying any existing processes, facilities or materials, making them viable commercially. And we have demonstrated our process on a more diverse array of substrates than ever before,” Lee said.
“Now you can put them on helmets, cell phones, convex windows, portable electronic devices, curved roofs, clothing – virtually anything,” said Zheng.
Moreover, peel-and-stick technology isn’t necessarily restricted to thin-film solar cells, Zheng said. The researchers believe the process can also be applied to thin-film electronics, including printed circuits and ultra thin transistors and LCDs.
“Obviously, a lot of new products – from ‘smart’ clothing to new aerospace systems – might be possible by combining both thin-film electronics and thin-film solar cells,” observed Zheng. “And for that matter, we may be just at the beginning of this technology. The peel-and-stick qualities we’re researching probably aren’t restricted to Ni/SiO2. It’s likely many other material interfaces demonstrate similar qualities, and they may have certain advantages for specific applications. We have a lot left to investigate.”
The authors of the Scientific Reports paper – “Peel-and-Stick: Fabricating Thin Film Solar Cell on Universal Substrates” – are Chi Hwan Lee, In Sun Cho and Xiaolin Zheng from Stanford’s Department of Mechanical Engineering, Dong Rip Kim from Hanyang University in Seoul, Korea, and Nemeth William and Qi Wang from the National Renewable Energy Laboratory in Denver, Colorado.
This article was written by Glen Martin, a freelance writer working for the Stanford University School of Engineering.
CLEARLAKE, Calif. – Local police officers helped spread Christmas cheer on Tuesday morning to several local families.
On Christmas morning the Clearlake Police Department Peace Officers Association held its annual Christmas present giveaway to deserving families in need.
This year has been a financially difficult year, yet the police officer’s association came together to select three families.
Early on Christmas morning, Det. Tim Alvarado and Det. Travis Lenz were accompanied by Santa Claus as they set out into the city to spread Christmas joy.
All the families selected were extremely appreciative in the receiving of gifts and the police officer association thanked the families for allowing them into their homes during this holiday.
LAKE COUNTY, Calif. – A young Clearlake man shot in the face during a Sunday confrontation remains hospitalized and in intensive care due to his injuries, with family saying his condition has worsened.
Steven Farnan, 20, was shot in the face following a physical fight that occurred at around 1 p.m. Sunday in the Clear Lake Riviera, as Lake County News has reported.
He fought with a subject at a residence in the 10000 block of Fairway Drive near Sierra Drive before another male shot him, according to witnesses.
Reports from the scene indicated the suspects fled the area in a blue hatchback.
As of early Tuesday, no arrests in the case had been made, according to jail booking records.
Farnan, now at an out-of-county hospital for treatment, suffered a shattered jaw from the gunshot, with the bullet going down his neck and hitting an artery. Early on, doctors had struggled to stop the bleeding before finally stabilizing him, his family reported.
However, early Tuesday his aunt, Kimberly Cochran of Montana, told Lake County News that Farnan had taken a turn for the worse.
She said he was in intensive care and that doctors could not do surgery to remove the bullet from his neck.
Cochran added that doctors are not sure if Farnan will survive his injury.
Farnan’s family asked anyone who has information about the suspect in his shooting to call the Lake County Sheriff’s Office.
The sheriff’s office can be reached through Central Dispatch at 707-263-2690 on the holiday or at 707-262-4200 during main business hours.
Email Elizabeth Larson at
LAKE COUNTY, Calif. – The wet fall and early winter are helping water supplies locally and around the state.
The rains over the last several weeks have pushed the level of Clear Lake up to its highest measure in more than a decade, according to lake records provided by Lake County Water Resources.
At the start of December Clear Lake went form roughly 2 feet Rumsey – the special measure used just for Clear Lake – to 5.25 feet Rumsey as of early Christmas morning, according to the US Geological Survey’s lake gauge.
That’s nearly twice the lake’s depth on Christmas 2011, and higher than all lake levels for Dec. 24 from 2001 through 2012, based on available records.
US Geological Survey gauges on streams around the county also show much increased depths.
Casse Forczek of Kelseyville has watched Kelsey Creek swell to the point of nearly overrunning its banks twice in the past month.
She shared a photo of the creek from earlier this week, which can be seen below, at the point of nearly overflowing.
Elsewhere in the state, rain and snow are helping California’s snowpack – a major water source for the state’s water users – bulk up.
Snowpack measurements provided through the California Department of Water Resources’ California Data Exchange Center early Tuesday showed that the statewide snowpack to be 119 percent of normal.
Showing how quickly such numbers can change, it had been at 140 percent of normal on Monday, Department of Water Resources data showed.
Email Elizabeth Larson at
LAKEPORT, Calif. – This handsome fellow is looking for a new companion or family who would welcome him into their home.
This male cat is a 7-year-old domestic long hair mix.
He has gold eyes, a long gray coat and weighs nearly 10 pounds.
He’s been neutered and vaccinated, and is ready to go home with a new owner once their application is approved.
Find him in cat room kennel No. 90, ID No. 35016.
To fill out an adoption application online visit http://www.co.lake.ca.us/Government/Directory/Animal_Care_And_Control/Adopt/Dog___Cat_Adoption_Application.htm .
Lake County Animal Care and Control is located at 4949 Helbush in Lakeport, next to the Hill Road Correctional Facility.
Office hours are Monday through Friday, 8 a.m. to 5 p.m., and 1 p.m. to 3 p.m., Saturday. The shelter is open from 10:30 a.m. to 4:30 p.m. Monday through Friday and on Saturday from 1 p.m. to 3 p.m.
Visit the shelter online at http://www.co.lake.ca.us/Government/Directory/Animal_Care_And_Control.htm .
For more information call Lake County Animal Care and Control at 707-263-0278.
Email Elizabeth Larson at
KELSEYVILLE, Calif. – The community is invited to celebrate the holiday season with a free meal at Kelseyville Presbyterian Church on Christmas day.
The church’s annual free Christmas dinner will be held Tuesday, Dec. 25, beginning at noon at the church, located at 5340 Third St., behind Westamerica Bank in Kelseyville.
All are welcome, and Santa is scheduled to stop in and visit.
If you are alone for the holiday, or in need of a hot meal, Chef Dennis Marshall and his crew will once again prepare the Christmas feast.
For those who want to help serve, help with the celebratory meal is always welcome.