Solution-processed quantum dots (QDs) have a high potential for fabricating low-cost, flexible, and large-scale solar energy harvesting devices. It has recently been demonstrated that hybrid devices employing a single monovalent cation perovskite solution for PbS QD surface passivation exhibit enhanced photovoltaic performance when compared to standard ligand passivation. Herein, we demonstrate that the use of a triple cation Cs 0.05(MA 0.17FA 0.83) 0.95Pb(I 0.9Br 0.1) 3 perovskite composition for surface passivation of the quantum dots results in highly efficient solar cells, which maintain 96% of their initial performance after 1200 h shelf storage. We confirm perovskite shell formation around the PbS nanocrystals by a range of spectroscopic techniques as well as high-resolution transmission electron microscopy. We find that the triple cation shell results in a favorable energetic alignment to the core of the dot, resulting in reduced recombination due to charge confinement without limiting transport in the active layer. Consequently, photovoltaic devices fabricated via a single-step film deposition reached a maximum AM1.5G power conversion efficiency of 11.3% surpassing most previous reports of PbS solar cells employing perovskite passivation.
Bibliographical noteFunding Information:
We thank Prof. Uwe Bunz for providing access to the device fabrication facilities and Prof. J. Zaumseil for access to SEM. This project has received funding from the European Research Council (ERC) under the Europen Union’s Horizon 2020 research and innovation programme (ERC Grant Agreement No. 714067, ENERGYMAPS).
© 2019 American Chemical Society.
- hybrid perovskite
- quantum dots
- solar cells
- triple cation
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy(all)