Paving the way for high-performance quantum dot solar cells

Lead selenide (PbSe) quantum dots (QDs) are investigated as the photovoltaic absorber material in a variety of designs based on the light and carrier collection management (LCCM) architecture (US Patent 8,294,025). This architecture uses a periodic array of nano-elements to produce both enhanced light trapping and photocarrier collection. Optical modeling is performed numerically for the various design variations and the results are compared. Superior light capture as well as enhanced photogenerated carrier collection are shown to be attainable with ultra-thin QD layers. PbSe QD LCCM devices give, on average, a 40% increase in J_SC over corresponding planar control devices, with a maximum improvement of 57.5%. Furthermore, the LCCM architecture allows for attaining J_SC values above what is possible for similar planar cells, while using significantly less absorber volume.