APPLICATIONS OF TECHNOLOGY:

• Organic-nanomaterial hybrid solar cell design

ADVANTAGES:

• Maximizes conversion efficiency
• Minimizes interface charge recombination
• Vastly reduces the possibility of electrical shorting
• Provides greater charge mobility
• Improves photon absorption

ABSTRACT:

The standard design of excitonic solar cells, which includes most organic-based solar cells, is ideal in only two out of three dimensions.   In other words, excitons can diffuse vertically and not reach a contact. Moreover, because the structure of real blended systems is less regular than the ideal structure, other problems that limit device performance arise, such as shorting and interface electronics.

Berkeley Lab researchers Alex Zettl and Jeffrey C. Grossman have invented a configuration and method for making an exciton-based photovoltaic cell that overcomes this problem. By using a controlled repeating structure, excitons interface in all three dimensions to minimize exciton recombination and maximize photovoltaic conversion efficiency.

The researchers have shown two ways to achieve the ideal structure for the nanoscale photovoltaic device:

1. In one configuration, the photovoltaic cell comprises rod-like structures in a three-dimensional crisscross or lattice pattern. As a result, the angular rods interrupt the incoming light in portions and significantly decrease the necessary exciton travel distance to the heterojunction in three dimensions.

2. In another configuration, the photovoltaic cell comprises a plurality of void-bearing molecules disposed in the polymer matrix that serve to provide the heterojunction.

The invention also comprises an improved configuration of the heterojunction. A variety of electron donor polymer and electron acceptor nanocomposite materials can be used in this invention, and both the donor and acceptor materials can be optically absorbing for higher efficiency.

STATUS:

• Published Patent Application PCT/US2009/058319 available at www.wipo.int. Available for licensing or collaborative research.

To learn more about licensing a technology from LBNL see http://www.lbl.gov/Tech-Transfer/licensing/index.html.

REFERENCE NUMBER: IB-2364

SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:

• High-Efficiency, Self-Concentrating Nanoscale Solar Cell, IB-2338
• Controlled Structure Of Organic/Nanomaterial Solar Cells, IB-2365
• Low Cost, High Efficiency Tandem Silicon Solar Cells, IB-2357
• Streamlined Synthesis of Binary Nanorods for Power-Efficient Nanocrystal Devices, IB-2490