Mark Lusk and his team at the Colorado School of Mines conducted several studies to considerably increase the solar cell efficiency.
This is an illustration of multiple-exciton generation (MEG). The left side shows an electron promoted to a high energy state (blue) plus the "hole" vacated by the electron (red). The right side shows the original exciton (now dark green/red) and a new exciton (light green/orange) after MEG. The top image shows a conceptualized version of the idea, while the bottom shows an actual exciton and bi-exciton using the same color scheme.
Recently, they have performed a research work on quantum dots, light-absorbing particles. The study demonstrates how the size affects quantum dots’ energy transfer ability for producing electricity. Quantum dots behave like atoms resulting in strange nanoscale electronic properties. These properties can be useful in altering the light interaction approach.
Multiple-exciton generation (MEG) refers to a theory that suggests it is possible for an electron with absorbed light energy, referred as an exciton, to transfer that absorbed energy to more than one electron. This results in high generation of electricity from the same amount of absorbed light. Lusk and collaborators’ research advance offers proof for this MEG concept. The connection among quantum dot size and MEG is an important topic among the researchers. Lusk and his team have utilized a high performance computer network, supported by the National Science Foundation (NSF), to analyze the relation between quantum dot size and MEG rate.
Researchers have discovered that every quantum dot possesses a solar spectrum that is ideal for MEG performance. It has also been found that MEG performance of smaller dots is more efficient compared to larger ones. Hence, the solar cells developed using quantum dots with solar spectrum can be more efficient when compared to solar cells made without quantum dots.
A program director for NSF’s Division of Materials Research, Mary Galvin, states that the study findings will help to solve an existing dispute within the renewable energy sector. In addition, the results will contribute for the development of new techniques to create highly efficient solar cells.