Featured Research

from universities, journals, and other organizations

Solar cells: Powered by nanoholes

Date:
July 8, 2014
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Increasing the cost-effectiveness of photovoltaic devices is critical to making these renewable energy sources competitive with traditional fossil fuels. One possibility is to use hybrid solar cells that combine silicon nanowires with low-cost, photoresponsive polymers. A simple and inexpensive fabrication procedure boosts the light-capturing capabilities of tiny holes carved into silicon wafers.

A simple and inexpensive fabrication procedure boosts the light-capturing capabilities of tiny holes carved into silicon wafers.

Related Articles


Increasing the cost-effectiveness of photovoltaic devices is critical to making these renewable energy sources competitive with traditional fossil fuels. One possibility is to use hybrid solar cells that combine silicon nanowires with low-cost, photoresponsive polymers. The high surface area and confined nature of nanowires allows them to trap significant amounts of light for solar cell operations. Unfortunately, these thin, needle-like structures are very fragile and tend to stick together when the wires become too long.

Now, findings by Xincai Wang from the A*STAR Singapore Institute of Manufacturing Technology and co-workers from Nanyang Technological University could turn the tables on silicon nanowires by improving the manufacturing of silicon 'nanoholes' -- narrow cavities carved into silicon wafers that have enhanced mechanical and light-harvesting capabilities.

Nanoholes are particularly effective at capturing light because photons can ricochet many times inside these openings until absorption occurs. Yet a practical understanding of how to fabricate these tiny structures is still lacking. One significant problem, notes Wang, is control of the initial stages of nanohole formation -- a crucial period that can often induce defects into the solar cell.

Instead of traditional time-consuming lithography, the researchers identified a rapid, 'maskless' approach to producing nanoholes using silver nanoparticles. First, they deposited a nanometre-thin layer of silver onto a silicon wafer which they toughened by annealing it using a rapid-burst ultraviolet laser. Careful optimization of this procedure yielded regular arrays of silver nanospheres on top of the silicon surface, with sphere size and distribution controlled by the laser annealing conditions.

Next, the nanosphere-silicon complex was immersed into a solution of hydrogen peroxide and hydrofluoric acid -- a mixture that eats away at silicon atoms directly underneath the catalytic silver nanospheres. Subsequent removal of the silver particles with acid produced the final, nanohole-infused silicon surface.

The team analyzed the solar cell activity of their nanohole interfaces by coating them with a semiconducting polymer and metal electrodes. Their experiments revealed a remarkable dependence on nanohole depth: cavities deeper than one micrometer showed sharp drops in power conversion efficiency from a maximum of 8.3 per cent due to light scattering off of rougher surfaces and higher series resistance effects.

"Our simple process for making hybrid silicon nanohole devices can successfully reduce the fabrication costs which impede the solar cell industry," says Wang. "In addition, this approach can be easily transferred to silicon thin films to develop thin-film silicon-polymer hybrid solar cells with even higher efficiency."


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Lei Hong, Xincai Wang, Hongyu Zheng, Lining He, Hao Wang, Hongyu Yu, Rusli. High efficiency silicon nanohole/organic heterojunction hybrid solar cell. Applied Physics Letters, 2014; 104 (5): 053104 DOI: 10.1063/1.4863965

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Solar cells: Powered by nanoholes." ScienceDaily. ScienceDaily, 8 July 2014. <www.sciencedaily.com/releases/2014/07/140708111017.htm>.
The Agency for Science, Technology and Research (A*STAR). (2014, July 8). Solar cells: Powered by nanoholes. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2014/07/140708111017.htm
The Agency for Science, Technology and Research (A*STAR). "Solar cells: Powered by nanoholes." ScienceDaily. www.sciencedaily.com/releases/2014/07/140708111017.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Brand Blocker' Glasses Blur Ads in Real Time

'Brand Blocker' Glasses Blur Ads in Real Time

Buzz60 (Jan. 28, 2015) A team of college students design and build a pair of goggles that will obscure any corporate branding from your field of vision. Jen Markham (@jenmarkham) has the story. Video provided by Buzz60
Powered by NewsLook.com
Amplifying Tiny Movements to Visualize the Invisible

Amplifying Tiny Movements to Visualize the Invisible

Reuters - Innovations Video Online (Jan. 28, 2015) A new video recording method that amplifies seemingly invisible motion could lead to a touch-free vital signs monitor, and offer a new tool for engineers to gauge stresses on bridges and tunnels in real time. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Boeing's Profit Soars

Boeing's Profit Soars

Reuters - Business Video Online (Jan. 28, 2015) Boeing delivered more commercial planes, especially 737s and 787s, fueling profit. But it issued a mixed outlook. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Robot Replacements for Foxconn's Workers

Robot Replacements for Foxconn's Workers

Reuters - Business Video Online (Jan. 28, 2015) Foxconn parent Hon Hai Precision Industry is looking to automation to keep productivity up without the rising costs of human labor. Meg Teckman reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins