Two researchers at the University of Notre Dame in Indiana, Pralay K. Santra and Professor Prashant V. Kamat, have discovered that a solar cell that is comprised of up to three layers of quantum dots. Each layer they discovered is tuned to a different part of the solar spectrum and has an efficiency that is up to 60% higher than the sum of the efficiencies of separate solar cells comprised of only one individual layer.
This new discovery of layered quantum dots might lead to new quantum dot solar cell designs with high efficiencies and broad-spectrum absorption.
Scientists are not 100% certain what is causing the synergistic effects but they suspect the dots’ band energies are in alignment so that electron transfer cascades from larger-band-gap dots to smaller-band-gap dots – the place electrons accumulate.
Or, the energy transfer from the larger-band-gap-dots to the smaller-band-gap-dots where concentrated excitation occurs may be the cause.
Scientists are still trying to determine how significant the tandem-layers quantum dot solar cell discovery is, but they are hoping it leads to new clues about how to design higher efficiency solar cells, and they are optimistic that that this will ultimately lead to future significant performance in solar cell performance.