We’ve known about Natcore Technology for the past two years. We’ve talked with their president twice, once for the inaugural issue of our print magazine and the other for our Solar Speaks podcast series as they refuse to rest on their laurels.
It may be time to talk to them again.
The research program of the company, being conducted under a joint research agreement with Rice University, is getting closer toward the realization of a manufacturable quantum dot solar cell. The work is being supervised by Prof. Andrew Barron, a Natcore co-founder.
Three key requirements must be met to make a quantum dot solar cell:
- Create quantum dots of the proper size;
- Create a uniform layer of those same quantum dots embedded in a thin film of silicon dioxide; and
- Arrange the quantum dots so the average inter-dot distance between any two of them is less than 10nm.
The scientists have met all three requirements by successfully embedding 20nm-diameter germanium quantum dots (Ge QDs) inside smooth, round shells of silica (silicon dioxide); dispersed the coated quantum dots on a surface with a simple spraying technique; and coated the layer with a film of silicon dioxide using Natcore’s liquid phase deposition (LPD) process. The coated quantum dots are represented by the chemical symbol Ge@SiO2.
Scanning electron microscopes and transmission electron microscope analysis of the films, coupled with a measurement of the photocurrent generated when the film was exposed to light, showed nearly 70% of the Ge@SiO2 quantum dots were within the 10nm maximum separation between nearest neighbors needed for high-efficiency device operation.The resulting samples were one square centimeter in size.
With an applied voltage across the film thickness and illuminated by a laboratory white light operating at approximately one sun intensity, the film produced a current of over 6 milliamps. The 6ma current represents a threefold increase over the first attempts to make a QD layer device, as reported by Natcore in an earlier news release.
“This is a remarkable improvement in photo-generated current in the silica film,” says Chuck Provini, Natcore’s president and CEO. “Prof. Barron’s group has done an excellent job moving this from scientific research through proof of concept. Now the researchers at our Rochester R&D Center will focus on developing a working prototype.”
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