Optical nanomaterials allow solar cell to repair itself

Jan. 5, 2011
Optical-nanomaterial-based solar cells created at Purdue University are designed to self-repair using carbon nanotubes and DNA, an approach aimed at increasing service life and reducing cost.

West Lafayette, IN--Optical-nanomaterial-based solar cells created at Purdue University are designed to self-repair using carbon nanotubes and DNA, an approach aimed at increasing service life and reducing cost.

The design exploits the electrical properties called single-walled carbon nanotubes, using them as "molecular wires in light-harvesting cells," as phrased by John Hyun Choi, an assistant professor of mechanical engineering at Purdue University.

In a photoelectrochemical cell, an electrolyte transports electrons and creates the current. The cells contain light-absorbing chromophores, chlorophyll-like molecules that unfortunately degrade upon exposure to sunlight. In the new technology, the photo-damaged chromophores are continuously replaced with new ones. As a result, a photoelectrochemical cell could continue operating at full capacity indefinitely, as long as new chromophores are added.

The findings were detailed in a November, 2010 at a presentation during the International Mechanical Engineering Congress and Exhibition (Vancouver, BC, Canada). The concept also was unveiled in an online article at SPIE's website.1

Molecular recognition
The carbon nanotubes work as a platform to anchor strands of DNA. The DNA has specific sequences of nucleotides that enable them to recognize and attach to the chromophores. "The DNA recognizes the dye molecules, and then the system spontaneously self-assembles," says Choi.

When the chromophores are ready to be replaced, they could be removed by using chemical processes or by adding new DNA strands with different nucleotide sequences, removing the damaged dye molecules. New chromophores could then be added.

Two elements are critical for the technology to mimic nature's self-repair mechanism: molecular recognition and thermodynamic metastability, or the ability of the system to continuously be dissolved and reassembled.

The research is an extension of work that Choi collaborated on with researchers at the Massachusetts Institute of Technology (Cambridge, MA) and the University of Illinois (Urbana, IL). The earlier work used biological chromophores taken from bacteria; findings were detailed in a research paper published in November in the journal Nature Chemistry.2

However, using natural chromophores is difficult, and they must be harvested and isolated from bacteria, a process that would be expensive to reproduce on an industrial scale, Choi says. "So instead of using biological chromophores, we want to use synthetic ones made of dyes called porphyrins," he notes.


REFERENCES:

1. http://spie.org/x41475.xml?ArticleID=x41475

2. http://www.nature.com/nchem/journal/v2/n11/abs/nchem.822.html

Follow us on Twitter

Subscribe now to Laser Focus World magazine; it’s free!

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

Request a quote: Micro 3D Printed Part or microArch micro-precision 3D printers

April 11, 2024
See the results for yourself! We'll print a benchmark part so that you can assess our quality. Just send us your file and we'll get to work.

Request a free Micro 3D Printed sample part

April 11, 2024
The best way to understand the part quality we can achieve is by seeing it first-hand. Request a free 3D printed high-precision sample part.

How to Tune Servo Systems: The Basics

April 10, 2024
Learn how to tune a servo system using frequency-based tools to meet system specifications by watching our webinar!

Precision Motion Control for Sample Manipulation in Ultra-High Resolution Tomography

April 10, 2024
Learn the critical items that designers and engineers must consider when attempting to achieve reliable ultra-high resolution tomography results here!

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!