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<p>Organic-inorganic halide perovskite solar cells have increased efficiencies substantially
(from 3% to > 22%), within a few years. However, these solar cells degrade very rapidly due to
humidity and no longer are capable of converting photons into electrons. Methylammonium
Lead Triiodide (CH3NH3PbI3 or MAPbI3) is the most common type of halide perovskite solar
cell and is the crystal studied in this thesis. Graphene is an effective encapsulation method of
MAPbI3 perovskite to reduce degradation, while also being advantageous because of its excellent
optical and conductive properties. Using a PMMA transfer method graphene was chemical vapor
depostion (CVD) grown graphene was transferred onto MAPbI3 and reduced the MAPbI3
degradation rate by over 400%. The PMMA transfer method in this study is scalable for roll-to-
roll manufacturing with fewer cracks, impurites, and folds improving upon dry transfer methods.
To characterize degradation a fluorescent microscope was used to capture photoluminescence
data at initial creation of the samples up to 528 hours of 80% humidity exposure. Atomic force
microscopy was used to characterize topographical changes during degradation. The study
proves that CVD graphene is an effective encapsulation method for reducing degradation of
MAPbI3 due to humidity and retained 95.3% of its initial PL intensity after 384 hours of 80%
humidity exposure. Furthermore, after 216 hours of 80% humidity exposure CVD graphene
encapsulated MAPbI3 retained 80.2% of its initial number of peaks, and only saw a 35.1%
increase in surface height. Comparatively, pristine MAPbI3 only retained 16% of its initial
number of peaks and saw a 159% increase in surface height.
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| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/8047580 |
| Date | 14 May 2019 |
| Creators | Kyle Reiter (6639662) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Reduced_Degradation_of_CH3NH3PbI3_Solar_Cells_by_Graphene_Encapsulation/8047580 |
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