Lessons learned from spiro-OMeTAD and PTAA in perovskite solar cells
File(s)
Published version
Author(s)
Rombach, Florine
Haque, Saif
Macdonald, Thomas
Type
Journal Article
Abstract
Organic semiconductors have become essential parts of thin-film electronic devices, particularly as hole transport layers (HTLs) in perovskite solar cells (PSCs) where they represent one of the major bottlenecks to further enhancements in both device stability and efficiency. Small molecule 2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD) and polymer poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) are two of the first successful HTLs used in PSCs, and have remained at the forefront of developing high efficiency devices for almost a decade. Since their first application, many investigations into the properties of spiro-OMeTAD and PTAA have contributed to a growing understanding of the mechanisms that enable their success as HTLs. This review summarizes and discusses the key electronic and morphological properties, doping strategies and mechanisms, and degradation mechanisms of both spiro-OMeTAD and PTAA. A critical comparison between the two materials is provided, highlighting both the similarities which explain their enduring popularity as well as key differences in electrical and morphological properties. From this analysis emerges an improved understanding of the fundamental properties that enable the persistent success of HTL materials, which are found to include not only hole conductivity, band gap, and morphology, but also interactions with dopants, the perovskite, and environmental stressors. The knowledge about these properties that are critically summarized in this review is also applicable to the many other types of organic electronic devices now employing spiro-OMeTAD and PTAA. A detailed examination of the properties of materials reveals a clear set of guiding principles for the development of future generation HTLs. Applying these design strategies to produce more advanced HTLs will be essential to further improve the stability, efficiency, and commercialization of PSCs.
Date Issued
2021-08-25
Date Acceptance
2021-08-03
Citation
Energy and Environmental Science, 2021, 14 (10), pp.5161-5190
ISSN
1754-5692
Publisher
Royal Society of Chemistry
Start Page
5161
End Page
5190
Journal / Book Title
Energy and Environmental Science
Volume
14
Issue
10
Copyright Statement
© The Royal Society of Chemistry 2021. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Royal Commission for the Exhibition of 1851
Identifier
https://pubs.rsc.org/en/content/articlelanding/2021/EE/D1EE02095A
Grant Number
EP/R020574/1
CHSA_P82337
Subjects
Science & Technology
Physical Sciences
Technology
Life Sciences & Biomedicine
Chemistry, Multidisciplinary
Energy & Fuels
Engineering, Chemical
Environmental Sciences
Chemistry
Engineering
Environmental Sciences & Ecology
HOLE-TRANSPORT MATERIALS
ORGANOMETAL HALIDE PEROVSKITE
POWER CONVERSION EFFICIENCY
LIGHT-EMITTING-DIODES
ENERGY-LEVEL SHIFTS
N-I-P
HIGH-PERFORMANCE
CHARGE-TRANSPORT
ORGANIC SEMICONDUCTORS
THERMAL-STABILITY
Energy
Publication Status
Published
Date Publish Online
2021-08-25