Prospect of near-infrared quantum dots in the development of tandem solar cells: Detail charge balance study

Abstract

The conventional single-junction solar cells (ex: monocrystalline silicon (cSi) and perovskite solar cells) are limited to 30% efficiency, known as the Shockley–Queisser limit. Due to operational constraints, the single-junction solar cells are transparent to a large part of the near-infrared (NIR) solar spectrum. Harvesting the unused NIR photons in tandem solar cells could be a potential way forward. However, the unavailability of suitable NIR bandgap semiconductors is a huge practical challenge in realising tandem solar cells. The advancement of nanotechnology has enabled size dependent tunability of energy bandgap of semiconductors quantum dots (QDs). It is shown here that NIR bandgap QDs can be used to augment the performance of the existing perovskite and cSi solar cells in tandem architecture. Using detailed charge balance calculation, the optimum bandgaps of QDs for the development of perovskite-QD and cSi-QD tandem solar cells have been identified. Further, It is also depicted that the QD solar cells can produce 11.8% and 5.2% efficiency by using the unused transmitted photons which improve the limiting efficiency from perovskite and cSi solar cells, respectively. In tandem solar cells, this may help realise 39.8% and 34.2% efficiency in the case of perovskite-QD and cSi-QD tandem solar cells.