Close

Search

Search Menu
Photonics Media Photonics Buyers' Guide Photonics Spectra BioPhotonics EuroPhotonics Vision Spectra Photonics Showcase Photonics ProdSpec Photonics Handbook
More News

Spectroscopy Probes the Energy-Level Landscape of Solar Cells

Facebook Twitter LinkedIn Email Comments
HEIDELBERG, Germany, Aug. 15, 2019 — A new spectroscopic method developed by researchers at Heidelberg University could enable scientists to study the physical principles of organic photovoltaics with extreme precision to better understand how energetic losses occur. The new method combines ultraviolet photoemission spectroscopy and argon cluster etching to allow scientists to directly visualize the vertical energetic landscape in the donor-acceptor blend.

The researchers investigated both model and high-performance photovoltaic systems using their new technique and demonstrated that the resulting photovoltaic gaps were in close agreement with the measured charge transfer energies and open-circuit voltages. They used the new spectroscopic technique to study the evolution of the energetic landscape upon environmental degradation, obtaining information that will help them understand degradation mechanisms and develop mitigation strategies. The spectroscopic method developed by the Heidelberg researchers can map the energetic landscape on a nanometer scale and can be applied at any point during the solar cell’s lifetime.

Artistic representation of an energetic landscape that determines the movement of photo-induced positive (h+) and negative (e-) charges in photovoltaic devices. Courtesy of Yana Vaynzof, Heidelberg University.

Artistic representation of an energetic landscape that determines the movement of photo-induced positive (h+) and negative (e-) charges in photovoltaic devices. Courtesy of Yana Vaynzof.

According to professor Yana Vaynzof, who led the research, the new technique solves a key problem in the field of organic photovoltaics. “Without mapping the energetic landscapes, it is difficult to understand how and why devices lose energy in the process of converting light into electricity,” she said. “Now we have a spectroscopic method that allows us to develop new generations of solar cells with reduced energy losses and improved performance.”

Until now, the standard approach has been to estimate the photovoltaic gap of the donor-acceptor blend using the energy values measured on the individual blend components. The researchers said that in the past, mapping energetic landscapes has been so challenging that only rough estimates could be used to study the fundamental processes in organic photovoltaic devices.

The research was published in Joule (https://doi.org/10.1016/j.joule.2019.06.018).  

Photonics.com
Aug 2019
GLOSSARY
ultraviolet photoemission spectroscopy
A technique for measuring the energy spectrum of electrons emitted during the absorption of ultraviolet radiation. This spectrum reveals the characteristic ionization energies of the molecules and facilitates study of their chemical natures.
Research & TechnologyeducationEuropeHeidelberg UniversityspectroscopyTest & Measurementphotovoltaicssolarenergyenvironmentorganic photovoltaicsphotovoltaic gapultraviolet photoemission spectroscopy

Comments
back to top
Facebook Twitter Instagram LinkedIn YouTube RSS
©2019 Photonics Media, 100 West St., Pittsfield, MA, 01201 USA, info@photonics.com

Photonics Media, Laurin Publishing
x We deliver – right to your inbox. Subscribe FREE to our newsletters.
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.