TY - JOUR
T1 - Molecular Weight Effect on the Absorption, Charge Carrier Mobility, and Photovoltaic Performance of an Indacenodiselenophene-Based Ladder-Type Polymer
AU - Intemann, Jeremy J.
AU - Yao, Kai
AU - Yip, Hin-Lap
AU - Xu, Yun-Xiang
AU - Li, Yong-Xi
AU - Liang, Po-Wei
AU - Ding, Fei-Zhi
AU - Li, Xiaosong
AU - Jen, Alex K.-Y.
PY - 2013/8/13
Y1 - 2013/8/13
N2 - Selenium substitution on a ladder-type indacenodithiophene-based polymer (PIDT-DFBT) is investigated in order to reduce band gap, improve charge mobilities, and enhance the photovoltaic performance of the material. The new indacenodiselenophene-based polymer (PIDSe-DFBT) possessed improved absorption over its sulfur analogue in films, as well as substantially higher charge mobilities (0.15 and 0.064 cm2/(V s) hole and electron mobility, respectively, compared to 0.002 and 0.008 cm2/(V s) for PIDT-DFBT). The enhanced material properties led to an improved power conversion efficiency of 6.8% in photovoltaic cells, a 13% improvement over PIDT-DFBT-based devices. Furthermore, we examined the effect of molecular weight on the properties of PIDSe-DFBT and found not only a strong molecular weight dependence on mobilities, but also on the absorptivity of polymer films, with each 15 000 g/mol increase in weight, leading to a 25% increase in the absorptivity of the material. The molecular weight dependence of the material's properties resulted in a significant difference in photovoltaic performance with the high-molecular-weight PIDSe-DFBT providing a higher photocurrent, fill factor, and efficiency due to its improved absorption and hole mobility. These results demonstrate the importance of achieving high molecular weight and the potential that selenium-containing ladder-type polymers have in the design of high-performance semiconducting polymers for organic photovoltaics (OPVs). © 2013 American Chemical Society.
AB - Selenium substitution on a ladder-type indacenodithiophene-based polymer (PIDT-DFBT) is investigated in order to reduce band gap, improve charge mobilities, and enhance the photovoltaic performance of the material. The new indacenodiselenophene-based polymer (PIDSe-DFBT) possessed improved absorption over its sulfur analogue in films, as well as substantially higher charge mobilities (0.15 and 0.064 cm2/(V s) hole and electron mobility, respectively, compared to 0.002 and 0.008 cm2/(V s) for PIDT-DFBT). The enhanced material properties led to an improved power conversion efficiency of 6.8% in photovoltaic cells, a 13% improvement over PIDT-DFBT-based devices. Furthermore, we examined the effect of molecular weight on the properties of PIDSe-DFBT and found not only a strong molecular weight dependence on mobilities, but also on the absorptivity of polymer films, with each 15 000 g/mol increase in weight, leading to a 25% increase in the absorptivity of the material. The molecular weight dependence of the material's properties resulted in a significant difference in photovoltaic performance with the high-molecular-weight PIDSe-DFBT providing a higher photocurrent, fill factor, and efficiency due to its improved absorption and hole mobility. These results demonstrate the importance of achieving high molecular weight and the potential that selenium-containing ladder-type polymers have in the design of high-performance semiconducting polymers for organic photovoltaics (OPVs). © 2013 American Chemical Society.
KW - conjugated polymers
KW - density functional theory
KW - ladder-type polymers
KW - organic field-effect transistors
KW - organic photovoltaics
KW - selenium
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U2 - 10.1021/cm401586t
DO - 10.1021/cm401586t
M3 - RGC 21 - Publication in refereed journal
SN - 0897-4756
VL - 25
SP - 3188
EP - 3195
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 15
ER -
