Imperial College London


Faculty of Natural SciencesDepartment of Chemistry

Professor of Photochemistry



+44 (0)20 7594 5321j.durrant Website




Miss Lisa Benbow +44 (0)20 7594 5883




G22CMolecular Sciences Research HubWhite City Campus






BibTex format

author = {Luke, J and Speller, EM and Wadsworth, A and Wyatt, MF and Dmiitrov, S and Lee, HKH and Li, Z and Tsoi, WC and McCulloch, I and Bagnis, D and Durrant, JR and Kim, J-S},
journal = {Advanced Energy Materials},
title = {Twist and degrade – Impact of molecular structure on the photostability of non-fullerene acceptors and their photovoltaic blends},
url = {},
year = {2019}

RIS format (EndNote, RefMan)

AB - Non-fullerene acceptors (NFAs) dominate organic photovoltaic (OPV) research due to their promising efficiencies and stabilities. However, there is very little investigation into the molecular processes of degradation, which is critical to guiding design of novel NFAs for long-lived, commercially viable OPVs. Here we investigate the important role of molecular structure and conformation on NFA photostability in air by comparing structurally similar but conformationally different promising NFAs; planar O-IDTBR and non-planar O-IDFBR. We identify a three-phase degradation process: (i) initial photo-induced conformational change (i.e. torsion about the Core-BT dihedral), induced by non-covalent interactions with environmental molecules, (ii) followed by photo-oxidation and fragmentation, leading to chromophore bleaching and degradation product formation, and (iii) finally complete chromophore bleaching.Initial conformational change is a critical prerequisite for further degradation, providing fundamental understanding of the relative stability of IDTBR and IDFBR, where the alreadytwisted IDFBR is more prone to degradation. When blended with the donor polymer P3HT, both NFAs exhibit improved photostability whilst the photostability of the polymer itself is significantly reduced by the more miscible twisted NFA. Our findings elucidate the important role of NFA molecular structure on photostability of OPV systems, and provide vital insights into molecular design rules for intrinsically photostable NFAs.
AU - Luke,J
AU - Speller,EM
AU - Wadsworth,A
AU - Wyatt,MF
AU - Dmiitrov,S
AU - Lee,HKH
AU - Li,Z
AU - Tsoi,WC
AU - McCulloch,I
AU - Bagnis,D
AU - Durrant,JR
AU - Kim,J-S
PY - 2019///
SN - 1614-6832
TI - Twist and degrade – Impact of molecular structure on the photostability of non-fullerene acceptors and their photovoltaic blends
T2 - Advanced Energy Materials
UR -
ER -