Tiny crystals promise big benefits for solar technologies
January 05, 2006
Los Alamos National Laboratory scientists have discovered that a phenomenon called carrier multiplication, in which semiconductor nanocrystals respond to photons by producing multiple electrons, is applicable to a broader array of materials that previously thought. The discovery increases the potential for the use of nanoscrystals as solar cell materials to produce higher electrical outputs than current solar cells.
In papers published recently in the journals Nature Physics and Applied Physics Letters, the scientists demonstrate that carrier multiplication is not unique to lead selenide nanocrystals, but also occurs with very high efficiency in nanocrystals of other compositions, such as cadmium selenide. In addition, these new results shed light on the mechanism for carrier multiplication, which likely occurs via the instantaneous photoexcitation of multiple electrons. Such a process has never been observed in macroscopic materials and it explicitly relies on the unique physics of the nanoscale size regime.
According to Richard Schaller, a Los Alamos scientist on the team, "Our research of carrier multiplication in previous years was really focused on analyzing the response of lead selenide nanocrystals to very short laser pulses. We discovered that the absorption of a single photon could produce two or even three excited electrons. We knew, somewhat instinctively, that carrier multiplication was probably not confined to lead selenide, but we needed to pursue the question."
Lead project scientist Victor Klimov explains, "Carrier multiplication actually relies upon very strong interactions between electrons squeezed within the tiny volume of a nanoscale semiconductor particle. That is why it is the particle size, not its composition that mostly determines the efficiency of the effect. In nanosize crystals, strong electron-electron interactions make a high-energy electron unstable. This electron only exists in its so-called 'virtual state' for an instant before rapidly transforming into a more stable state comprising two or more electrons."
The Los Alamos findings point toward practical photovoltaic technologies that may utilize such traditional solar cell materials as cadmium telluride, which is very similar to cadmium selenide. Other interesting opportunities may also be associated with the use of carrier multiplication in solar-fuel technologies and specifically, the production of hydrogen by photo-catalytic water splitting. The latter process requires four electrons per water molecule and its efficiency can be dramatically enhanced if these multiple electrons can be produced via a single-photon absorption event.
DOE/Los Alamos National Laboratory
Related Solar Technologies Current Events and Solar Technologies News ArticlesSolar could meet California energy demand 3 to 5 times over
In the face of global climate change, increasing the use of renewable energy resources is one of the most urgent challenges facing the world.A ray of sunshine for bioenergy
Even at historically low natural gas prices, bioenergy may not be out of the running -- it just may need a little help from the sun. A new study from researchers at the University of Minnesota examining the financial viability of solar-heated biomass gasification technologies that produce a natural gas substitute product concludes that combining these renewable resources can make economic sense. Calculating the future of solar-fuel refineries
A team of University of Wisconsin-Madison engineers has developed a new tool to help plot the future of solar fuels. NTU invents smart window that tints and powers itself
Nanyang Technological University (NTU) scientists have developed a smart window which can darken or brighten without the need for an external power source.New technique offers spray-on solar power
Pretty soon, powering your tablet could be as simple as wrapping it in cling wrap.Wind energy cuts the electricity bill
The promoting of renewable energy is at the heart of the current debate on energy policy.Net energy analysis should become a standard policy tool, Stanford scientists say
Policymakers should conduct "net energy analyses" when evaluating the long-term sustainability of energy technologies, according to new Stanford University research. NREL Finds Up to 6-cent per Kilowatt-Hour Extra Value with Concentrated Solar Power
Concentrating Solar Power (CSP) projects would add additional value of 5 or 6 cents per kilowatt hour to utility-scale solar energy in California where 33 percent renewables will be mandated in six years, a new report by the Energy Department's National Renewable Energy Laboratory has found.Solar energy prospects are bright for Scotland, experts say
Installing state-of-the-art solar panels on a quarter of a million roofs could meet one-sixth of Scotland's electricity demands, experts say. Wind farms can provide society a surplus of reliable clean energy, Stanford study finds
The worldwide demand for solar and wind power continues to skyrocket. Since 2009, global solar photovoltaic installations have increased about 40 percent a year on average, and the installed capacity of wind turbines has doubled.
More Solar Technologies Current Events and Solar Technologies News Articles
A Golden Thread: 2500 Years of Solar Architecture and Technology|
by Ken Butti (Author), John Perlin (Author)
Green Power Homes - Quick Guide To : Electricity From Solar Panels ; Solar Water Heating ; Wind Turbine Technology ; Geothermal Heating And Cooling|
by William Dollinger
Green Power Homes - Quick And Easy Guide to Wind, Solar and Geothermal Energy
If you have heard the concepts of Sustainable energy, Sustainable
living, Eco energy, Green homes and never knew what it is all about,
then this quick guide will introduce you to these concepts.
Ever wondered what Wind power is all about ? How to heat
your water with Solar panels ? Is it possible to cool your home using
geothermal forces ?
In this quick guide you'll find :
About The History Of Wind EnergyHow Wind Turbines Work And The Advantages And Disadvantages Of
Wind PowerAnswers To Common Questions Such As : How Much Does A Wind
System Cost?Case StudiesAbout The History Of Solar EnergyWhat Is Passive Solar...
Solar Energy, Technology Policy, and Institutional Values|
by Frank N. Laird (Author)
Energy policies influence the shape of emergent technological systems, and also condition our social, political, and economic lives. This book demonstrates the difficulties of deliberating such properties by providing a historical case study that analyzes U.S. renewable energy policy from the end of World War II through the energy crisis of the 1970s. It illuminates the ways beliefs and values come to dominate official problem frames and get entrenched in institutions.
How to Solar Power Your Home Everything You Need to Know Explained Simply (Back-To-Basics Conserving)|
by Martha Maeda (Author)
Now more than ever, the question of economic and environmentally friendly energy sources has become a hot topic in almost every American home. With that in mind, more and more people are turning to alternatives such as solar power as a means of saving money and reducing their imprint on the environment. This nearly carbon neutral method comes with hefty tax rebates from the federal government and in states like California and New Jersey massive rebates from the state. More states are considering similar rebates and with a 3 to 8 year energy savings possible according to a recent report by the New York Times, it is an ideal solution for anyone looking to save money in the long term and help the planet immediately.
This book will guide anyone interested in the process of installing...
Solar Energy Focus (October 2014)|
by Cougar Solar
Solar Energy Focus is the number one resource for individuals and businesses interested in solar energy (and renewable energy). The magazine is both informative and educative as it covers current news across the UK and internationally on solar energy and renewable energy. It also provides technology guides to help you with your buying decision.
Solar Energy Focus is your portal to the world of Solar Energy.
Solar Power: How to Save A LOT of Money the Easy Way (Solar Power, Save Money, Solar Energy, Solar, Sustainable Energy, Sustainable Homes, Sustainability)|
Discover The Ideal Way To Save A LOT Of Money Without Affecting Your Life By Using Solar Power
This book contains proven steps and strategies on how to save money by utilizing a clean, renewable, and sustainable energy source - that is solar power.
This book will also help you understand the basic concepts about solar energy and solar electric systems. This information is important to fully understand the concept of solar power holistically. Moreover, found in this book are important purchasing considerations and many other reminders.
You can gain a whole new perspective on providing power for your home from the information in this book. While you are at it, you will realize how much money you will be able to save when you decide to go for solar power...
Advanced Solar Cell Technologies (The Science of Electricity)|
by Mark Fennell
This book discusses the most important of the advanced solar cell technologies. The first chapter discusses the reasons for low efficiency in a solar cell and the basic methods for improving efficiency. Subsequent topics include: thin films, anti-reflective coatings, surface texturing, minority carriers, solar concentrators, and stacking.
Table of Contents
1. Possible Events in a Solar Cell and Resulting Efficiency
2. Anti-Reflective Coating
3. Surface Texturing
4. Optical Thickness
6. Preventing Electron-Hole Pairs From Recombining
7. Using More of Reflected Waves
8. Using Waves That Travel Through the Cell
9. Reducing the Energy Lost as Heat
10. Thin Films
11. Solar Concentrators
Solar Photovoltaics - Fundamentals, Technologies and Applications (English) 3rd Edition|
by Chetan Singh Solanki (Author)
This thoroughly revised text, now in its third edition, continues to provide a detailed discussion on all the aspects of solar photovoltaic (PV) technologies from physics of solar cells to manufacturing technologies, solar PV system design and their applications. The Third Edition includes a new chapter on Advances in C-Si Cell Processes Suitable for Near Future Commercialization (Chapter 8) to introduce the technological advancement in the commercial production to keep the readers up to date.
Organized in three parts, Part I introduces the fundamental principles of solar cell operation and design, Part II explains various technologies to fabricate solar cells and PV modules and Part III focuses on the use of solar photovoltaic as part of the system for providing electrical...
101 Facts... Solar System. Space Books for Kids. Amazing Facts, Photos & Video. (101 Space Facts for Kids Book 4)|
by IP Factly
IP Factly presents... "101 Facts… Solar System!"
Solar System Kids Book - Amazing facts, stunning photos plus videos telling the story of the solar system for kids.
Space books for kids - a fun and fascinating way for young readers to discover more about the planets, dwarf planets and other fascinating objects in the Solar System.
This planet book for kids mixes facts, stunning photos and even Videos to encourage and bolster independent reading.
Accompanying webpage with video clips
This book provides fact after fact for information hungry children to tell family and friends, and even has an accompanying webpage with video clips giving a visual insight into the Solar System.
The video links mean children come back again and...
Real Goods Solar Living Source Book--Special 30th Anniversary Edition: Your Complete Guide to Renewable Energy Technologies and Sustainable Living|
by John Schaeffer (Author)
Concerns over dwindling resources and environmental degradation are driving many to seek alternatives to our wasteful, polluting lifestyle. Clean technologies such as solar power, wind power, and biodiesel fuel are soaring in popularity. Real Goods Solar Living Source Book—Special 30th Anniversary Edition is the ultimate guide to renewable energy, sustainable living, green building, homesteading, off-the-grid living, and alternative transportation, written by experts with decades of experience and a passion for sharing their knowledge. This fully updated edition includes brand-new sections on Peak Oil, climate change, relocalization, natural burial, biodynamics, and permaculture. It also boasts the latest product listings and completely rewritten and expanded chapters on: Land and...