Luminescent Coupling in Perovskite Tandem Solar Cells: The Advantages of Perovskite and Luminescent Coupling in Photovoltaics

Multijunction or tandem solar cells are made of multiple semiconductor light absorbing layers. Having multiple absorber layers in a solar cell allows it to absorb a larger range of the solar spectrum. When electrons recombine (relax to a lower energy state) in the top layer of a tandem solar cell, they can emit luminescent photons that are absorbed by the bottom layer of the cell. This process is called luminescent coupling, and it can be used to enhance the performance of photovoltaic cells. Another strategy to increase solar cell performance is to use perovskite as the absorber layer material. Currently, about 95% of commercial solar cells are single-junction silicon cells, however, perovskite tandem solar cells have been gaining research interest due to perovskites’ tunable bandgap, long-range charge transport, and high absorption [1]. Perovskites are also ferroelectric, so they can hold a polarization without an applied external electric field [6]. Perovskites and luminescent coupling are areas of active research in understanding and improving the performance of tandem solar cells, and both effects have the potential to increase the voltage, current, and efficiency of solar cells. This paper will first discuss how single junction and tandem solar cells operate, then look at the advantages of using perovskite materials in tandem solar cells, and will finally look at three studies on the impacts of luminescent coupling in tandem solar cells.