Title
Incorporating Fluorine Substitution into Conjugated Polymers for Solar Cells: Three Different Means, Same Results
Date Issued
02 February 2017
Access level
open access
Resource Type
journal article
Author(s)
University Park
Publisher(s)
American Chemical Society
Abstract
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: ∼5.2% efficiency with a short-circuit current (Jsc) at ∼11 mA cm-2, an open-circuit voltage (Voc) at 0.77 V, and a fill factor (FF) of ∼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. (Graph Presented).
Start page
2059
End page
2068
Volume
121
Issue
4
Language
English
OCDE Knowledge area
Ciencia de los polímeros
Química física
Scopus EID
2-s2.0-85012932762
Source
Journal of Physical Chemistry C
ISSN of the container
19327447
Sponsor(s)
MAK, QZ, and WY were supported by a NSF grant (DMR-1507249) and the Office of Naval Research (Grant No. N000141410221). DN and SR acknowledge financial support by the German Ministry of Science and Education (Project UNVEIL, FKZ 13N13719). YL, BK, QW, and EDG acknowledge financial support from the Office of Naval Research, United States, under Grant no. N000141410532.
Sources of information:
Directorio de Producción Científica
Scopus