Plastic solar power

Harnessing the power of the largest celestial object in the
universe is not just the stuff of science fiction ““ it may
soon become an efficient way to power everything from cell phones
to Las Vegas casinos.

Showcasing their work in the most recent issue of “Nature
Materials,” professor of materials science and engineering
Yang Yang, postdoctoral researcher Gang Li and graduate student
Vishal Shrotriya have created a new type of solar cell that they
say may revolutionize the way many think of solar power.

In response to the world’s growing dependency on natural
gas and fossil fuels, solar power is being thought of as an
attractive solution due in large part to the fact that the sun is
the most abundant source of energy in the universe, Shrotriya
said.

The idea is enticing enough: Imagine being capable of easily
capturing the sun’s rays, translating them into power and
creating a clean, environmentally-friendly energy source without
any harmful by-products.

In fact, an area slightly larger than the size of Maryland
““ 160 miles long by 160 miles wide ““ completely covered
with solar panels could power all of the United States, Li said.
Currently, solar power provides less than one percent of the
world’s energy.

But before residents and industries begin installing solar
panels onto their homes and businesses, there is at least one
forboding obstacle ““ money.

The cost of solar power per kilowatt is at least four times that
of coal or natural gas. And while the price of solar cells is
slowly decreasing, the solar module itself presents a huge barrier
to making the energy source affordable.

That is, until Yang and his research group came up with a new
type of solar cell made of the same substance as a grocery
store’s plastic shopping bag.

“The solar cell is similar to the material used to make
those plastic bags, and those things can be very cheap,” Li
said.

For the group’s solar cell, Yang uses a special type of
flexible polymer found in a variety of everyday plastics and
equates the process of making his cell to painting a wall or a
house.

A polymer, like a little bit of paint, can go a long way to
covering a large wall. Yang and his team hope that their polymer
material could be easily spread and coated onto a substrate. This
coated substrate would generate electricity capable of powering
anything that conventional power sources do today.

About 90 percent of the current solar cell market is dominated
by cell systems made from silicon, which unlike Yang’s
plastic cells are largely cost-ineffecient.

The appearance of silicon is similar to a wafer in that a solar
cells need to be put together piece by piece. The process is
tedious, and silicon is in high demand for other uses.

“The most popular use of silicon is to build computer
chips. From one piece of silicon you can build a lot of computer
chips, but it’s not enough to even build one solar
cell,” Yang said.

The high demand for silicon, the long refining process and
limited supply all contribute to its high cost, which translates
into expensive solar cells which many do not find feasible.

Members of the UCLA research group say their plastic solar cells
could be a unique solution to the barriers associated with using
silicon cells, that is of course, if they can ensure a long
lifetime for their product.

The average conventional solar cell usually lasts for 20 to 25
years, but the life expectancy for the group’s plastic solar
cell is decidedly lower.

Due to the low lifetime of the UCLA group’s plastic solar
cells, the technology is now being looked at by industry experts in
an attempt to lengthen it. The target for the plastic solar
cell’s lifespan is 15 to 20 years, and Yang said he hopes to
commercialize his cell within three to five years.

The goal is necessary, scientists at UCLA say, because as oil
and gas prices rise to an all-time high and the United States
becomes ever more dependent on these conventional energy sources,
an affordable and efficient alternative could solve many
problems.

“We hope that ultimately solar energy can be extensively
used in the commercial sector as well as the private sector …
there are such a wide variety of applications,” Yang said in
a UCLA press release.