Solar panels need to convert solar energy into electricity, which requires an electric field to separate positive and negative charges. Because of this, manufacturers typically spend a lot of money doping each layer of a solar cell with relevant chemicals.
New research from Lawrence Berkeley National Laboratory offers a new and easier way. Made in the lab from cesium germanium tribromide (CsGeBr3 or CGB), the new ferroelectric material is said to offer a simpler and less expensive way to make solar cell devices. The findings were recently published in the journal Science Advances.
“This new ferroelectric material opens a more convenient door for making solar cell devices,” said the researchers. “Unlike conventional solar materials, CGB crystals are inherently polarized, which means that one side of the crystal will naturally A positive charge is created, and a negative charge is created on the other side. So no chemical doping is required.”
Not only that, but the material is a lead-free “halide perovskite,” an emerging affordable and easy-to-manufacture solar material. Often, the best-performing halide perovskites contain lead, which can pollute the environment and cause public health concerns. However, the above-mentioned new materials do not contain lead, and the performance is not affected.
“Imagine a lead-free solar material that not only harvests energy from the sun, but also has a natural, spontaneously formed electric field, a very exciting prospect for the solar and electronics industries,” the researchers said.
It’s also worth mentioning that the researchers found that the light absorption of CGBs is tunable — spanning the visible to ultraviolet spectrum, an ideal range for high energy conversion efficiency in solar cells. They point out that such tunability is rarely found in conventional ferroelectrics.
The researchers also noted that CGBs could not only reduce the manufacturing cost of solar cells, but could also be used to advance a new generation of sensors and ultra-stable memory devices that respond to light.
“We anticipate that this study will open a path for further exploration of this class of semiconducting ferroelectric materials and unearth new possibilities for multifunctional materials such as opto-ferroelectric materials,” they concluded.