Solution-processed colloidal quantum dots (CQDs) are promising optoelectronic materials; however, CQD solids have, to date, exhibited either excellent transport properties but fusion among CQDs or limited transport when QDs are strongly passivated. Here, we report the growth of monolayer perovskite bridges among quantum dots and show that this enables the union of surface passivation with improved charge transport. We grow the perovskite layer after forming the CQD solid rather than introducing perovskite precursors into the quantum dot solution: the monolayer of perovskite increases interdot coupling and decreases the distance over which carriers must tunnel. As a result, we double the diffusion length relative to reference CQD solids and report solar cells that achieve a stabilized power conversion efficiency (PCE) of 13.8%, a record among Pb chalcogenide CQD solar cells.
|Original language||English (US)|
|State||Published - Jun 9 2020|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): OSR-2018-CARF/CCF-3079
Acknowledgements: This work was supported by Ontario Research Fund-Research Excellence program (ORF7-Ministry of Research and Innovation, Ontario Research Fund-Research Excellence Round 7), and by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under award no. OSR-2018-CRG7-373702 and award no. OSR-2018-CARF/CCF-3079. This work used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. We thank A.R. Kirmani for GISAXS and GIWAXS discussions. We thank L. Goncharova for assistance with RBS measurements. We thank A.H. Proppe, L. Chiluka, Y. Hou, M. Biondi, Y. Wang, M. Vafaei, and G. Bappi for manuscript discussion. We thank D. Kopilovic, E. Palmiano, L. Levina, and R. Wolowiec for technical support. B.S. conceived the idea of this study; B.S. developed the perovskite monolayer CQD system, fabricated and characterized solar cell devices, and performed SIMS and materials stability tests; O.V. assisted in RBS measurements and analysis; M.W. assisted in the fabrication of quantum dot in matrix samples and absorption and photoluminescence measurements; A.J. Y.G. and F.L. carried out transient absorption measurements and data analysis; Z.J. and H.Z. carried out GISAXS and GIWAXS measurements; X.Z. J.L. O.M.B. and Y.G. assisted the HRTEM measurements; C.X. and D.B. carried out the TRTS measurement and mobility extraction; M.-J.C. performed SEM imaging measurements; Y.D. assisted in 2PTA measurement; S.-W.B assisted device preparation for certification; and F.P.G.d.A. and E.H.S. supervised the project. B.S. A.J. F.P.G.d.A. and E.H.S. wrote the manuscript, and all authors discussed the results and assisted in the preparation of the manuscript. The authors declare no competing interests.