TY - JOUR
T1 - Chemical and Structural Degradation of CH3NH3PbI3 Propagate from PEDOT:PSS Interface in the Presence of Humidity
AU - Thomas, Sara A.
AU - Hamill, J. Clay
AU - White, Sarah Jane O.
AU - Loo, Yueh Lin
N1 - Funding Information:
This work is supported by undergraduate research funding and an Innovative Research in Energy and the Environment award from the Andlinger Center for Energy and the Environment at Princeton University awarded to S.J.O.W. and Y‐L.L. Y‐L.L. also acknowledges the support from Princeton Catalysis Initiative. The authors acknowledge the use of Princeton's Imaging and Analysis Center, which is partially supported by the Princeton Center for Complex Materials, a National Science Foundation (NSF)‐MRSEC program (DMR‐1420541). The authors also acknowledge Dr. Melissa Ball (Princeton University, Department of Chemical and Biological Engineering) for helpful review of the manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Funding Information:
This work is supported by undergraduate research funding and an Innovative Research in Energy and the Environment award from the Andlinger Center for Energy and the Environment at Princeton University awarded to S.J.O.W. and Y-L.L. Y-L.L. also acknowledges the support from Princeton Catalysis Initiative. The authors acknowledge the use of Princeton's Imaging and Analysis Center, which is partially supported by the Princeton Center for Complex Materials, a National Science Foundation (NSF)-MRSEC program (DMR-1420541). The authors also acknowledge Dr. Melissa Ball (Princeton University, Department of Chemical and Biological Engineering) for helpful review of the manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Publisher Copyright:
© 2021 Wiley-VCH GmbH
PY - 2021/8/23
Y1 - 2021/8/23
N2 - Understanding interfacial reactions that occur between the active layer and charge-transport layers can extend the stability of perovskite solar cells. In this study, the exposure of methylammonium lead iodide (CH3NH3PbI3) thin films prepared on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-coated glass to 70% relative humidity (R.H.) leads to a perovskite crystal structure change from tetragonal to cubic within 2 days. Interface-sensitive photoluminescence measurements indicate that the structural change originates at the PEDOT:PSS/perovskite interface. During exposure to 30% R.H., the same structural change occurs over a much longer time scale (>200 days), and a reflection consistent with the presence of (CH3)2NH2PbI3 is detected to coexist with the cubic phase by X-ray diffraction pattern. The authors propose that chemical interactions at the PEDOT:PSS/perovskite interface, facilitated by humidity, promote the formation of dimethylammonium, (CH3)2NH2+. The partial A-site substitution of CH3NH3+ for (CH3)2NH2+ to produce a cubic (CH3NH3)1−x[(CH3)2NH2]xPbI3 phase explains the structural change from tetragonal to cubic during short-term humidity exposure. When (CH3)2NH2+ content exceeds its solubility limit in the perovskite during longer humidity exposures, a (CH3)2NH2+-rich, hexagonal phase of (CH3NH3)1−x[(CH3)2NH2]xPbI3 emerges. These interfacial interactions may have consequences for device stability and performance beyond CH3NH3PbI3 model systems and merit close attention from the perovskite research community.
AB - Understanding interfacial reactions that occur between the active layer and charge-transport layers can extend the stability of perovskite solar cells. In this study, the exposure of methylammonium lead iodide (CH3NH3PbI3) thin films prepared on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-coated glass to 70% relative humidity (R.H.) leads to a perovskite crystal structure change from tetragonal to cubic within 2 days. Interface-sensitive photoluminescence measurements indicate that the structural change originates at the PEDOT:PSS/perovskite interface. During exposure to 30% R.H., the same structural change occurs over a much longer time scale (>200 days), and a reflection consistent with the presence of (CH3)2NH2PbI3 is detected to coexist with the cubic phase by X-ray diffraction pattern. The authors propose that chemical interactions at the PEDOT:PSS/perovskite interface, facilitated by humidity, promote the formation of dimethylammonium, (CH3)2NH2+. The partial A-site substitution of CH3NH3+ for (CH3)2NH2+ to produce a cubic (CH3NH3)1−x[(CH3)2NH2]xPbI3 phase explains the structural change from tetragonal to cubic during short-term humidity exposure. When (CH3)2NH2+ content exceeds its solubility limit in the perovskite during longer humidity exposures, a (CH3)2NH2+-rich, hexagonal phase of (CH3NH3)1−x[(CH3)2NH2]xPbI3 emerges. These interfacial interactions may have consequences for device stability and performance beyond CH3NH3PbI3 model systems and merit close attention from the perovskite research community.
KW - PEDOT:PSS
KW - interfacial reaction
KW - methylammonium lead iodide
KW - perovskite
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U2 - 10.1002/admi.202100505
DO - 10.1002/admi.202100505
M3 - Article
AN - SCOPUS:85111417991
SN - 2196-7350
VL - 8
JO - Advanced Materials Interfaces
JF - Advanced Materials Interfaces
IS - 16
M1 - 2100505
ER -