Greatly Improved Solar Cells

Apr 21, 2004
PbSeNQD

Victor Klimov and Richard Schaller at Los Alamos National Laboratory have enhanced the phenomenon called "impact ionization," which can significantly improve the efficiency of the conversion of solar energy to electrical current. Normally, an incident photon striking a semiconductor produces an electron-hole pair plus a bit of heat. By using sub-10-nm sized nanoparticles made of lead and selenium atoms, the Los Alamos scientists encourage the interaction to spawn a second exciton instead of the heat (see picture, which shows hi-resolution TEM image of epitaxially fused PbSe NanoQuantumDot pair.

Greatly improved solar cells might result from the use of a photophysical process in which for each incident solar photon not one but two excitons (electron-hole pairs) are created, says Physics News Update. As with photosynthesis what happens in a solar cell is the conversion of light energy into a small current of electrons; in plants the freed electrons helps to build glucose; in solar cells the currents are collected in the form of electricity.

Although they haven't yet built a working solar cell, they are the first to demonstrate the efficacy of getting the PbSe nanocrystals to render more photo-current. Implementing the new process might result in efficiency gains of more than 35% in the conversion of light to current. (Physical Review Letters, upcoming article)

See also the group website.


Explore further: Greenland darkening to continue, predicts CCNY expert Marco Tedesco

Related Stories

Devices or divisive: Mobile technology in the classroom

8 hours ago

Little is known about how new mobile technologies affect students' development of non-cognitive skills such as empathy, self-control, problem solving, and teamwork. Two Boston College researchers say it's ...

Recommended for you

United States, China team explore energy harvesting

Apr 18, 2015

Six authors have described their work in harvesting energy in a paper titled "Ultrathin, Rollable, Paper-Based Triboelectric Nanogenerator for Acoustic Energy Harvesting and Self-Powered Sound Recording." ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.