Subscribe free to our newsletters via your
  Solar Energy News  




Subscribe free to our newsletters via your




















SOLAR DAILY
NREL theorizes defects could improve solar cells
by Staff Writers
Golden CO (SPX) Jan 20, 2016


Schematic of a 'good' defect (red cross), which helps collection of electrons from photo-absorber (n-Si), and blocks the holes, hence suppresses carriers recombination.

Scientists at the Energy Department's National Renewable Energy Laboratory (NREL) are studying what may seem paradoxical - certain defects in silicon solar cells may actually improve their performance. The findings run counter to conventional wisdom, according to Pauls Stradins, the principal scientist and a project leader of the silicon photovoltaics group at NREL.

Deep-level defects frequently hamper the efficiency of solar cells, but NREL theoretical research suggests that defects with properly engineered energy levels can improve carrier collection out of the cell, or improve surface passivation of the absorber layer. Researchers at NREL ran simulations to add impurities to layers adjacent to the silicon wafer in a solar cell.

Namely, they introduced defects within a thin tunneling silicon dioxide (SiO2) layer that forms part of "passivated contact" for carrier collection, and within the aluminum oxide (Al2O3) surface passivation layer next to the silicon (Si) cell wafer. In both cases, specific defects were identified to be beneficial.

The simulations were accomplished using NREL's supercomputer and the National Energy Research Scientific Computing Center.

The research by Stradins, Yuanyue Liu, Su-Huai Wei, Hui-Xiong Deng, and Junwei Luo, "Suppress carrier recombination by introducing defects: The case of Si solar cell," appears in Applied Physics Letters.

Finding the right defect was key to the process. To promote carrier collection through the tunneling SiO2 layer, the defects need to have energy levels outside the Si bandgap but close to one of the band edges in order to selectively collect one type of photocarrier and block the other.

In contrast, for surface passivation of Si by Al2O3, without carrier collection, a beneficial defect is deep below the valence band of silicon and holds a permanent negative charge. The simulations removed certain atoms from the oxide layers adjacent to the Si wafer, and replaced them with an atom from a different element, thereby creating a "defect." For example, when an oxygen atom was replaced by a fluorine atom it resulted in a defect that could possibly promote electron collection while blocking holes.

The defects were then sorted according to their energy level and charge state. More research is needed in order to determine which defects would produce the best results. The principles used in this study are applicable to other materials and devices, such as photoanodes and two-dimensional semiconductors.

A recent study by the same authors has shown that the addition of oxygen could improve the performance of those semiconductors. For solar cells and photoanodes, engineered defects could possibly allow thicker, more robust carrier-selective tunneling transport layers or corrosion protection layers that might be easier to fabricate.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
National Renewable Energy Laboratory
All About Solar Energy at SolarDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
SOLAR DAILY
Cheaper solar cells with 20.2 percent efficiency
Lausanne, Switzerland (SPX) Jan 19, 2016
EPFL scientists have developed a solar-panel material that can cut down on photovoltaic costs while achieving competitive power-conversion efficiency of 20.2%. Some of the most promising solar cells today use light-harvesting films made from perovskites - a group of materials that share a characteristic molecular structure. However, perovskite-based solar cells use expensive "hole-transpor ... read more


SOLAR DAILY
BESC study seeks nature's best biocatalysts for biofuel production

Preventing food waste better strategy than turning it into biogas

Second-generation biofuels can reduce emissions

NREL's Min Zhang keeps her 'hugs' happy, leading to biofuel breakthroughs

SOLAR DAILY
Microbots individually controlled using 'mini force fields'

Russian Scientists Developing Avatar Robot for Extraterrestrial Exploration

NASA Marshall Center to Host FIRST Robotics Kick-Off at USSRC

Will computers ever truly understand what we're saying

SOLAR DAILY
Strong winds help Denmark set wind energy world record

Moventas Exceed receives DNV GL gearbox certification

Moventas rolls out breakthrough repairs for Siemens 2.3

Allianz and OX2 sign 21 MW wind power deal in Finland

SOLAR DAILY
Ghost town tests self-driving cars of tomorrow

Renault shares keep on skidding on emission fears

Daimler Trucks eyes swift return to post-sanctions Iran

US pledges $4 bn to speed self-driving cars

SOLAR DAILY
Fuel cell advance

Superoxide gives lithium-air batteries a jolt

Creation of Jupiter interior, a step towards room temp superconductivity

Companies mostly dump their coal ash in poor, minority communities

SOLAR DAILY
Belgium fails to reassure Luxembourg over nuclear safety: official

IAEA Starts Assessment of Japan's Efforts on Safe Use of Nuclear Plants

Japan to send plutonium cache to US under nuclear deal: report

Graphene filter can clean nuclear wastewater

SOLAR DAILY
ChemChina buys stake in Swiss energy trader Mercuria

How will climate policy affect energy access goals

Energy efficiency may encourage greater demand

What motivates people to walk and bike? It varies by income

SOLAR DAILY
NUS study shows the causes of mangrove deforestation in Southeast Asia

The Amazon's future

Tens of millions of trees in danger from California drought

Modeling Amazonian transitional forest micrometeorology




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement