TY  - JOUR
A1  - Samson, Stephanie
A1  - Rech, Jeromy
A1  - Perdigon-Toro, Lorena
A1  - Peng, Zhengxing
A1  - Shoaee, Safa
A1  - Ade, Harald
A1  - Neher, Dieter
A1  - Stolterfoht, Martin
A1  - You, Wei
T1  - Organic solar cells with large insensitivity to donor polymer molar mass across all acceptor classes
JF  - ACS applied polymer materials
N2  - Donor polymer number-average molar mass (M-n) has long been known to influence organic photovoltaic (OPV) performance via changes in both the polymer properties and the resulting bulk heterojunction morphology. The exact nature of these M-n effects varies from system to system, although there is generally some intermediate M-n that results in optimal performance. Interestingly, our earlier work with the difluorobenzotriazole (FTAZ)-based donor polymer, paired with either N2200 (polymer acceptor) or PC61BM (fullerene acceptor), PcBm demonstrated <10% variation in power conversion efficiency and a consistent morphology over a large span of M-n (30 kg/mol to over 100 kg/mol). Would such insensitivity to polymer M-n still hold true when prevailing small molecular acceptors were used with FTAZ? To answer this question, we explored the impact of FTAZ on OPVs with ITIC, a high-performance small-molecule fused-ring electron acceptor (FREA). By probing the photovoltaic characteristics of the resulting OPVs, we show that a similar FTAZ mn insensitivity is also found in the FTAZ:ITIC system. This study highlights a single-donor polymer which, when paired with an archetypal fullerene, polymer, and FREA, results in systems that are largely insensitive to donor M. Our results may have implications in polymer batch-to-batch reproducibility, in particular, relaxing the need for tight M-n control during synthesis.
KW  - polymer solar cells
KW  - conjugated polymers
KW  - fullerenes
KW  - fluorination
KW  - molecular weight
KW  - non-fullerene acceptors
KW  - power conversion efficiency
Y1  - 2020
U6  - https://doi.org/10.1021/acsapm.0c01041
SN  - 2637-6105
VL  - 2
IS  - 11
SP  - 5300
EP  - 5308
PB  - American Chemical Society
CY  - Washington
ER  -