(July 15, 2015) It’s
snack time: you have a plain oatmeal cookie, and a pile of chocolate chips.
Both are delicious on their own, but if you can find a way to combine them
smoothly, you get the best of both worlds.
Researchers in The Edward S. Rogers Sr. Department of
Electrical & Computer Engineering used this insight to invent something
totally new: they’ve combined two promising solar cell materials together for
the first time, creating a new platform for LED technology.
The team designed a way to embed strongly luminescent
nanoparticles called colloidal quantum dots (the chocolate chips) into
perovskite (the oatmeal cookie). Perovskites are a family of materials that can
be easily manufactured from solution, and that allow electrons to move swiftly
through them with minimal loss or capture by defects.
The work is published today in the international journal
Nature.
“It’s a pretty novel idea to blend together these two
optoelectronic materials, both of which are gaining a lot of traction,” says
Xiwen Gong (ECE), one of the study’s lead authors and a PhD candidate working
with Professor Ted Sargent (ECE). “We wanted to take advantage of the benefits
of both by combining them seamlessly in a solid-state matrix.”
The result is a black crystal that relies on the perovskite
matrix to ‘funnel’ electrons into the quantum dots, which are extremely
efficient at converting electricity to light. Hyper-efficient LED technologies
could enable applications from the visible-light LED bulbs in every home, to
new displays, to gesture recognition using near-infrared wavelengths.