TY - JOUR
T1 - Effect of asymmetric solubility of diketopyrrolopyrrole-based polymers and PC71BMs in a binary solvent system on the performance of bulk heterojunction solar cells
AU - Son, Seon Kyoung
AU - Lee, Hyo Sang
AU - Ha, Jae Seung
AU - Kim, Kyung Hwan
AU - Son, Hae Jung
AU - Ko, Min Jae
AU - Kim, Honggon
AU - Lee, Doh Kwon
AU - Kim, Jin Young
AU - Lee, Wonmok
AU - Park, Sungnam
AU - Choi, Dong Hoon
AU - Kim, Bongsoo
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2014/5
Y1 - 2014/5
N2 - In this study, we demonstrated the effective morphological control of polymer:fullerene blends using three separate solvent systems: chloroform (CF), CF:1,8-diiodooctane (DIO), and CF:o-dichlorobenzene (ODCB). The polymer:fullerene blends are composed of two diketopyrrolopyrrole (DPP)-based polymers of P(DPP-alt-QT) and P(DPP-alt-DTBSe) and a fullerene derivative of [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), i.e., P(DPP-alt-QT):PC71BM or P(DPP-alt-DTBSe):PC71BM. The CF:ODCB binary solvent exhibited the best photovoltaic performance among the three solvent systems for both polymer-based devices, although the CF:DIO also exhibited an improved performance compared to the CF system. By examining film morphology of the blend films, we found that the CF:ODCB enabled the most optimal nanoscale phase separation and the morphological features were strongly affected by the solubility of each material in the high boiling-point (BP) solvent. Specifically, the polymers have limited but slightly higher solubility in ODCB than in DIO, while the PC71BM molecules have a high solubility in both DIO and ODCB. Therefore, this work highlights that the optimally asymmetric solubility of each photoactive component in the high BP solvent is a critical factor to form the nanoscale, bicontinuous domains in the blend films and thereby to determine the performance of photovoltaic devices.
AB - In this study, we demonstrated the effective morphological control of polymer:fullerene blends using three separate solvent systems: chloroform (CF), CF:1,8-diiodooctane (DIO), and CF:o-dichlorobenzene (ODCB). The polymer:fullerene blends are composed of two diketopyrrolopyrrole (DPP)-based polymers of P(DPP-alt-QT) and P(DPP-alt-DTBSe) and a fullerene derivative of [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), i.e., P(DPP-alt-QT):PC71BM or P(DPP-alt-DTBSe):PC71BM. The CF:ODCB binary solvent exhibited the best photovoltaic performance among the three solvent systems for both polymer-based devices, although the CF:DIO also exhibited an improved performance compared to the CF system. By examining film morphology of the blend films, we found that the CF:ODCB enabled the most optimal nanoscale phase separation and the morphological features were strongly affected by the solubility of each material in the high boiling-point (BP) solvent. Specifically, the polymers have limited but slightly higher solubility in ODCB than in DIO, while the PC71BM molecules have a high solubility in both DIO and ODCB. Therefore, this work highlights that the optimally asymmetric solubility of each photoactive component in the high BP solvent is a critical factor to form the nanoscale, bicontinuous domains in the blend films and thereby to determine the performance of photovoltaic devices.
KW - Binary solvent system
KW - Hole mobility
KW - Morphology
KW - Organic photovoltaics
KW - Polymer solar cell
KW - Power conversion efficiency
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U2 - 10.1016/j.solmat.2014.02.011
DO - 10.1016/j.solmat.2014.02.011
M3 - Article
AN - SCOPUS:84897821422
VL - 124
SP - 232
EP - 240
JO - Solar Energy Materials and Solar Cells
JF - Solar Energy Materials and Solar Cells
SN - 0927-0248
ER -