TY - JOUR

T1 - Role of Nonfullerene Acceptor Impurities and Purification on the Efficiency and Stability of Organic Photovoltaics

AU - Kumari, Tanya

AU - Ahmadpour, Mehrad

AU - Morin, Pierre Olivier

AU - Ahmad, Mariam

AU - Atajanov, Rovshen

AU - Rindom, Cecilie

AU - Oh, Jiyeon

AU - Yakoob, Mohammed Amir

AU - Bergeron, Jean Sébastien

AU - Grenier, François

AU - Yang, Changduk

AU - Nielsen, Mogens Brøndsted

AU - Turkovic, Vida

AU - Madsen, Morten

N1 - Funding Information: This research was funded by the Independent Research Fund Denmark, Technology and Production Sciences (grant number 0136‐00081B) and Project ReactPV (grant number 8022‐00389B). Publisher Copyright: © 2023 The Authors. Solar RRL published by Wiley-VCH GmbH.

PY - 2023

Y1 - 2023

N2 - The introduction of nonfullerene acceptors (NFAs) has pushed the power conversion efficiency and organic photovoltaics (OPV) device stability to new standards. In this aspect, removal of trace impurities from one purification stage to the next is frequently stressed throughout the synthesis of photoactive OPV materials and NFAs to obtain the highest-purity material. However, detailed studies of the effect of purification on device performance are less reported. Herein, the role of NFA trace impurities on the optoelectronic characteristics and lifetime of resulting OPV devices is studied. The optimization of PBDB-T:ITIC-X devices, with various ITIC purity levels (X), has been thoroughly studied via a combination of photophysical, chemical, morphological, electrical, and optical characterization techniques, to shine light on the role of these impurities on device performance and lifetime. The findings suggest that, even in materials with larger concentrations of trace impurities, careful tuning can produce high efficiencies. Interestingly, the less-pure materials lead to longer device lifetimes along with an enhancement in accumulative power generation by a factor 3, compared to the purest ITIC-based devices. This demonstrates that selecting a material with the highest purity may not always be the best option for NFA OPV and that any positive effects of NFA purification must be carefully considered in light of both the device efficiency and stability.

AB - The introduction of nonfullerene acceptors (NFAs) has pushed the power conversion efficiency and organic photovoltaics (OPV) device stability to new standards. In this aspect, removal of trace impurities from one purification stage to the next is frequently stressed throughout the synthesis of photoactive OPV materials and NFAs to obtain the highest-purity material. However, detailed studies of the effect of purification on device performance are less reported. Herein, the role of NFA trace impurities on the optoelectronic characteristics and lifetime of resulting OPV devices is studied. The optimization of PBDB-T:ITIC-X devices, with various ITIC purity levels (X), has been thoroughly studied via a combination of photophysical, chemical, morphological, electrical, and optical characterization techniques, to shine light on the role of these impurities on device performance and lifetime. The findings suggest that, even in materials with larger concentrations of trace impurities, careful tuning can produce high efficiencies. Interestingly, the less-pure materials lead to longer device lifetimes along with an enhancement in accumulative power generation by a factor 3, compared to the purest ITIC-based devices. This demonstrates that selecting a material with the highest purity may not always be the best option for NFA OPV and that any positive effects of NFA purification must be carefully considered in light of both the device efficiency and stability.

KW - accumulative power generation

KW - lifetime

KW - nonfullerene acceptors

KW - organic photovoltaics

KW - trace impurities

U2 - 10.1002/solr.202300047

DO - 10.1002/solr.202300047

M3 - Journal article

AN - SCOPUS:85150078623

VL - 7

JO - Solar RRL

JF - Solar RRL

SN - 2367-198X

IS - 9

M1 - 2300047

ER -