TY  - JOUR
A1  - Kelly, Mary Allison
A1  - Roland, Steffen
A1  - Zhang, Qianqian
A1  - Lee, Youngmin
A1  - Kabius, Bernd
A1  - Wang, Qing
A1  - Gomez, Enrique D.
A1  - Neher, Dieter
A1  - You, Wei
T1  - Incorporating Fluorine Substitution into Conjugated Polymers for Solar Cells
BT  - three Different Means, Same Results
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - Fluorinating conjugated polymers is a proven strategy for creating high performance materials in polymer solar cells, yet few studies have investigated the importance of the fluorination method. We compare the performance of three fluorinated systems: a poly(benzodithieno-dithienyltriazole) (PBnDT-XTAZ) random copolymer where 50% of the acceptor units are difluorinated, PBnDT-mFTAZ where every acceptor unit is monofluorinated, and a 1:1 physical blend of the difluorinated and nonfluorinated polymer. All systems have the same degree of fluorination (50%) yet via different methods (chemically vs physically, random vs regular). We show that these three systems have equivalent photovoltaic behavior:,similar to 5.2% efficiency with a short-circuit current (J(sc)) at,similar to 11 mA cm(-2), an open-circuit voltage (v(oc)) at 0.77 V, and a fill factor (FF) of similar to 60%. Further investigation of these three systems demonstrates that the charge generation, charge extraction, and charge transfer state are essentially identical for the three studied systems. Transmission electron microscopy shows no significant differences in the morphologies. All these data illustrate that it is possible to improve performance not only via regular or random fluorination but also by physical addition via a ternary blend. Thus, our results demonstrate the versatility of incorporating fluorine in the active layer of polymer solar cells to enhance device performance.
Y1  - 2017
U6  - https://doi.org/10.1021/acs.jpcc.6b10993
SN  - 1932-7447
VL  - 121
IS  - 4
SP  - 2059
EP  - 2068
PB  - American Chemical Society
CY  - Washington
ER  -