Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Gradient Multi-Layer Nano-films for Photovoltaic and other applications

GML (Gradient Multi-Layer) nano-film
GML (Gradient Multi-Layer) nano-film

Abstract:
Recently, a new type of nanostructure - GML (Gradient Multi-Layer) nano-film - attracted attention of the researchers in the solar cell industry. The properties of this structure can be used in design of more efficient and less expensive solar cells, as well as other nano-structured devices.

Gradient Multi-Layer Nano-films for Photovoltaic and other applications

Posted on October 7th, 2010

GML Nano films

Quantum Dots are spherical nano-particles (or nano-crystals) typically made of semiconductor or metal.

Nano-structured Materials (or Devices) typically contain two or more interpenetrating nano-scale networks (Bulk Hetero Junctions or BHJs) including Organic (Polymer Blends), Inorganic (Quantum Dots only), and Hybrid (Polymer with Embedded Quantum Dots).

Gradient Multi-Layer (GML) Nano-structure (or nano-film) is a stack of Quantum Dot layers arranged to form a size gradient, composition gradient, density gradient or composition/size modulation with the strict control of each layer thickness and composition. The GML nano-film may include two or more types of Quantum Dot material to form Bulk Hetero Junctions or it can be embedded in the organic material (polymer).

GML Nano films have been described so far in only a few publications i.e. "Microchemical Nanofactories", US Patent Publ. 20080108122 (chemical method of building GML Nano); "Nanophotovoltaic Device with Improved Quantum Efficiency", US Patent Publ. 2008142075 2008.(mine); "Energy transfer between quantum dots of different sizes for quantum dot solar cells", 34th PV Spec.Conf., 2009 (Stanford research).

GML Nano films applications for PhotoVoltaics

Assembly of Quantum Dot layers can be designed to efficiently absorb the most of the Sun spectrum (0.3-2.0+ eV) by size and composition tuning. Specifically, one type of Quantum Dots can be selected from the low band-gap material (i.e. PbSe, InAs, Ge, others) to be able to absorb InfraRead part of the spectrum, and by tuning the QDs' sizes Quantum Dots made from the same material will absorb "green/yellow" part. The other Quantum Dots may have a wider band gap to absorb the "blue/UV" part of Spectrum. Due to the Quantum Confinement light absorption in Quantum Dot layers is very strong so the entire Sun spectrum can be absorbed within several tens to a hundred of nanometers.

Quantum Dots generally exhibit Multi Exciton Generation (MEG) phenomena, i.e. generation of more than one electron-hole pair by a single high-energy photon. GML Nano-films, containing low band gap QD's are expected to exhibit and utilize this phenomena, at least in some portion of the film thus enhancing Power Conversion Efficiency of GML Nano-film solar cell.

Size gradient in the GML Nano film creates corresponding gradient of the electro-chemical potential, which is equivalent to generation of high built-in Electric field in the film, which enhances transport of electrons and holes thus improving internal quantum efficiency (IQE) and photo current.

GML Nano films can exhibit phenomena of light trapping and photon re-emission, which additionally enhances IQE.

In case the efficient method of building GML Nano film is available the efficient PV structure can be formed that will provide the highest possible Power Conversion Efficiency.

PV expectations and main challenges

Theoretically, assuming a perfect transport (IQE), Multi Exciton Generation and perfect light trapping/photon re-emission and max possible Voc, the PCE can reach 65+% (still below the thermodynamic limit of about 86%). It is, however, a very challenging goal (see e.g. "Prospects of Nanostructure-Based Solar Cells...", Int. Journ. Of Photoenergy, 2009, id 154059).

One challenge here is to design a GML Nano structure in such precise and well-controlled way that allows for successful utilizing most or all of the above advantages of QD systems. But, even if the "smart" design of an efficient GML Nano structure had been available it would be unclear as to how to build such a structure in a well controlled, reliable, inexpensive and production-worthy way.

This represent another big challenge as most of the known methods of building nanostructured material are either unable to form a GML Nano structure (spin-coating, generally all solution coating methods) or are very expensive with low throughput and difficulties to be transferred to a full-scale production environment (Atomic Layer Deposition (ALD), Langmuir-Blodget or Microchemical method of US 20080108122).

####

For more information, please click here

Contacts:
Dr. Boris Gilman

Copyright © Coolsol R&C

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

Cool Calculations for Cold Atoms: New theory of universal three-body encounters September 2nd, 2014

Accounting for Biological Aggregation in Heating and Imaging of Magnetic Nanoparticles September 2nd, 2014

Engineers develop new sensor to detect tiny individual nanoparticles September 2nd, 2014

Future solar panels September 2nd, 2014

Energy

New synthesis method may shape future of nanostructures, clean energy: Findings advance efficient solar spliting of water into hydrogen fuel September 2nd, 2014

Future solar panels September 2nd, 2014

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

Aspen Aerogels, Inc. to Present at Barclays CEO Energy-Power Conference August 27th, 2014

Quantum Dots/Rods

Interaction between Drug, DNA for Designing Anticancer Drugs Studied in Iran August 17th, 2014

NANOPARTICLES INDIA August 8th, 2014

Researchers create quantum dots with single-atom precision June 30th, 2014

New Los Alamos Approach May Be Key to Quantum Dot Solar Cells With Real Gains in Efficiency: Nanoengineering Boosts Carrier Multiplication in Quantum Dots June 19th, 2014

Solar/Photovoltaic

Future solar panels September 2nd, 2014

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Eco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturing: UMass Amherst team invents a way to create versatile, water-soluble nano-modules August 13th, 2014

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE