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Title: Role of 4- tert -Butylpyridine as a Hole Transport Layer Morphological Controller in Perovskite Solar Cells

Abstract

Hybrid organic-inorganic materials for high efficiency, low cost photovoltaic devices have seen rapid progress since the introduction of lead based perovskites and solid-state hole transport layers. Although majority of the materials used for perovskite solar cells (PSC) are introduced from dye-sensitized solar cells (DSSCs), the presence of a perovskite capping layer as opposed to a single dye molecule (in DSSCs) changes the interactions between the various layers in perovskite solar cells. 4-tert-butylpyridine (tBP), commonly used in PSCs, is assumed to function as a charge recombination inhibitor, similar to DSSCs. However, the presence of a perovskite capping layer calls for a re-evaluation of its function in PSCs. Using TEM (transmission electron microscopy), we first confirm the role of tBP as a HTL morphology controller in PSCs. Our observations suggest that tBP significantly improves the uniformity of the HTL and avoids accumulation of Li salt. We also study degradation pathways by using FTIR (Fourier transform infrared spectroscopy) and APT (atom probe tomography) to investigate and visualize in 3-dimensions the moisture content associated with the Li salt. Long term effects, over 1000 hours, due to evaporation of tBP have also been studied. Based on our findings, a PSC failure mechanism associated with themore » morphological change of the HTL is proposed. tBP, the morphology controller in HTL, plays a key role in this process and thus this study highlights the need for additive materials with higher boiling points for consistent long term performance of PSCs.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340870
Report Number(s):
PNNL-SA-121464
Journal ID: ISSN 1530-6984; 49095
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nano Letters; Journal Volume: 16; Journal Issue: 9
Country of Publication:
United States
Language:
English
Subject:
perovskite solar cells; hole transport layer; transmission electron microscopy; focused ion beam; Fourier transform infrared spectroscopy; Environmental Molecular Sciences Laboratory

Citation Formats

Wang, Shen, Sina, Mahsa, Parikh, Pritesh, Uekert, Taylor, Shahbazian, Brian, Devaraj, Arun, and Meng, Ying Shirley. Role of 4- tert -Butylpyridine as a Hole Transport Layer Morphological Controller in Perovskite Solar Cells. United States: N. p., 2016. Web. doi:10.1021/acs.nanolett.6b02158.
Wang, Shen, Sina, Mahsa, Parikh, Pritesh, Uekert, Taylor, Shahbazian, Brian, Devaraj, Arun, & Meng, Ying Shirley. Role of 4- tert -Butylpyridine as a Hole Transport Layer Morphological Controller in Perovskite Solar Cells. United States. doi:10.1021/acs.nanolett.6b02158.
Wang, Shen, Sina, Mahsa, Parikh, Pritesh, Uekert, Taylor, Shahbazian, Brian, Devaraj, Arun, and Meng, Ying Shirley. 2016. "Role of 4- tert -Butylpyridine as a Hole Transport Layer Morphological Controller in Perovskite Solar Cells". United States. doi:10.1021/acs.nanolett.6b02158.
@article{osti_1340870,
title = {Role of 4- tert -Butylpyridine as a Hole Transport Layer Morphological Controller in Perovskite Solar Cells},
author = {Wang, Shen and Sina, Mahsa and Parikh, Pritesh and Uekert, Taylor and Shahbazian, Brian and Devaraj, Arun and Meng, Ying Shirley},
abstractNote = {Hybrid organic-inorganic materials for high efficiency, low cost photovoltaic devices have seen rapid progress since the introduction of lead based perovskites and solid-state hole transport layers. Although majority of the materials used for perovskite solar cells (PSC) are introduced from dye-sensitized solar cells (DSSCs), the presence of a perovskite capping layer as opposed to a single dye molecule (in DSSCs) changes the interactions between the various layers in perovskite solar cells. 4-tert-butylpyridine (tBP), commonly used in PSCs, is assumed to function as a charge recombination inhibitor, similar to DSSCs. However, the presence of a perovskite capping layer calls for a re-evaluation of its function in PSCs. Using TEM (transmission electron microscopy), we first confirm the role of tBP as a HTL morphology controller in PSCs. Our observations suggest that tBP significantly improves the uniformity of the HTL and avoids accumulation of Li salt. We also study degradation pathways by using FTIR (Fourier transform infrared spectroscopy) and APT (atom probe tomography) to investigate and visualize in 3-dimensions the moisture content associated with the Li salt. Long term effects, over 1000 hours, due to evaporation of tBP have also been studied. Based on our findings, a PSC failure mechanism associated with the morphological change of the HTL is proposed. tBP, the morphology controller in HTL, plays a key role in this process and thus this study highlights the need for additive materials with higher boiling points for consistent long term performance of PSCs.},
doi = {10.1021/acs.nanolett.6b02158},
journal = {Nano Letters},
number = 9,
volume = 16,
place = {United States},
year = 2016,
month = 9
}