2D phase purity determines charge-transfer yield at 3D/2D lead halide perovskite heterojunctions
File(s)
Supporting information
Accepted version
Author(s)
Type
Journal Article
Abstract
Targeted functionalization of 3D perovskite with a 2D passivation layer via R-NH3I treatment has emerged as an effective strategy for enhancing both the efficiency and chemical stability of ABX3 perovskite solar cells, but the underlying mechanisms behind these improvements remain unclear. Here, we assign a passivation mechanism where R-NH3I reacts with excess PbI2 in the MAPbI3 film and unsaturated PbI6 octahedra to form (R-NH3)2(MA)n-1PbnI3n+1. Crucially, we show that precise control of the 2D (R-NH3)2(MA)n-1PbnI3n+1 layer underpins performance improvements: n = 1 yields over a 2-fold improvement in hole injection to the HTL; n > 1 deteriorates hole injection. Ultrafast transient absorption spectroscopy suggests this n-dependence is rooted in the fact that fast (<6 ns) hole injection does not occur between the 3D and 2D layers. These results help explain contemporary empirical findings in the field and set out an important design rule for the further optimization of multidimensional perovskite optoelectronics.
Date Issued
2021-04-08
Date Acceptance
2021-03-16
Citation
Journal of Physical Chemistry Letters, 2021, 12, pp.3312-3320
ISSN
1948-7185
Publisher
American Chemical Society
Start Page
3312
End Page
3320
Journal / Book Title
Journal of Physical Chemistry Letters
Volume
12
Copyright Statement
© 2021 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry Letters, after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.jpclett.1c00362
Sponsor
Engineering and Physical Sciences Research Council
Engineering & Physical Science Research Council (EPSRC)
Engineering and Physical Sciences Research Council
Engineering & Physical Science Research Council (E
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/33769059
Grant Number
EP/L015277/1
EP/R020574/1
EP/P032591/1
DJR01350
Subjects
Energy-Generating Resources
Photochemistry
Solar Energy
Chemistry, Physical
Spectroscopy, Near-Infrared
X-Ray Diffraction
Fluorescence
Absorption
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2021-03-26