Nano Complex Solar Cells
A Korean research team has succeeded in developing a technology for a new structure that can greatly improve the efficiency of organic solar cells, which are receiving a lot of attention as next-generation energy devices.
Pohang University of Science and Technology (POSTECH) announced on Oct. 18 that one of its research teams headed by Cho Gil-won, professor of the Department of Chemical Engineering, and Cho Sae-byuk, successfully developed a technology for a new structure that can drastically improve optical conversion efficiency, regardless of the kinds of polymer semiconductor materials used in organic solar cells.
The research team utilized the fact that currents that are created after organic solar cells are exposed to light have a tendency to sensitively respond to subtle changes in an electric field. First, they created another ferroelectric nanocomplex film between a photoactive layer of a semiconductor polymer and an electrode of a solar cell, based on the idea that the use of a ferroelectric polymer makes it possible to arrange a magnetic dipole in the film in one direction.
The inserted film plays a role as a faucet for currents, which allows created electrons and holes to flow toward the positive or negative poles. Therefore, the loss of optical current can be minimized. By slowly adding millimeter seconds to the outside electric field, it is possible to systemically control the photoelectromotive force of the device and to effectively extract an optimal level of optical current for each semiconductor polymer.
Through the technology, the research team was able to increase the life expectancy of a photocharge by more than 80 percent and to improve its efficiency from 10 percent to 400 percent compared to existing solar cells. In particular, the study is significant in that the research team successfully overcame the shortcoming of every semiconductor polymer that is used in organic solar cells. Every semiconductor polymer needs an element structure that can be used to precisely control efficiency.
Professor Cho Gil-won noted, “Our research team suggested a model with an element structure for the first time, which can be used in next-generation organic semiconductors,” adding, “I think that based on this research, our team will be able to contribute to the development of highly-efficient and low-cost flexible organic solar cells for printing.”
The research findings were featured as a cover article by Advanced Energy Materials, a monthly scientific journal published by Wiley-VCH.