Last year, the University of Toronto had achieved double digit quantum dot solar cell efficiency for lead sulfide at 12 percent but now, researchers at the National Renewable Energy Laboratory (NREL) at U.S. Department of Energy have attained a new world record for efficiency for quantum dot solar cells at 13.4 percent.
Basically electronic materials, colloidal quantum dots offer exiting optical properties because of their amazingly small size that ranges between 3 to 20 nanometers in dimension. Back in 2010 when quantum dot solar cells were first discovered, it was a boon as a technology to track research efforts in order to extract electricity from sunlight, but the initial efficiency of lead sulfide only managed to offer 2.9 percent. Now, within a year since the University of Toronto bettered it, NREL branch has come back to regain the record.
CsPbI3 New Compound That Paved Way for Improved Efficiency
These improvements in efficiency is a result of improved understanding of the connection between independent quantum dots, their overall structure, and reducing faults in quantum dots. The recent developments in quantum dot solar cells has come from a completely distinct material called as cesium lead triiodide with chemical symbol of CsPbI3. This compound comes from the recently discovered family of halide perovskite materials and has the ability to produce phenomenally large voltage at an open circuit, of about 1.2 volts.
As per one of the senior scientist and project lead at NREL in the department of Chemical materials and nanoscience, Joseph Luther, this voltage when collaborated with material’s bandgap can transform it into an ideal subject for the top layer in a multijunction solar cell.