TY - JOUR
T1 - Improved photovoltaic performance of a nonfullerene acceptor based on a benzo[b]thiophene fused end group with extended π-conjugation
AU - Yang, Kun
AU - Liao, Qiaogan
AU - Koh, Chang Woo
AU - Chen, Jianhua
AU - Su, Mengyao
AU - Zhou, Xin
AU - Tang, Yumin
AU - Wang, Yang
AU - Zhang, Youming
AU - Woo, Han Young
AU - Guo, Xugang
N1 - Funding Information:
X. G. is grateful to National Science Foundation of China (NSFC, 21774055), Shenzhen Basic Research Fund (JCYJ20170817105905899), Shenzhen Peacock Plan Project (KQTD20140630110339343), J. C. acknowledges Basic Research Fund of Shenzhen City (JCYJ20170817104319061) and the China Postdoctoral Science Foundation (2018M631727), Y. W. acknowledges the China Postdoctoral Science Foundation (No. 2018M630267) and the SUSTech Presidential Postdoctoral Fellowship. Y. Z. acknowledges the China Postdoctoral Science Foundation (2017M622748). H. Y. W. thanks the financial support from the NRF of Korea (2016M1A2A2940911 and 2015M1A2A2057506).
Funding Information:
X. G. is grateful to National Science Foundation of China (NSFC, 21774055), Shenzhen Basic Research Fund (JCYJ20170817105905899), Shenzhen Peacock Plan Project (KQTD20140630110339343), J. C. acknowledges Basic Research Fund of Shenzhen City (JCYJ20170817104319061) and the China Postdoctoral Science Foundation (2018M631727), Y. W. acknowledges the China Postdoctoral Science Foundation (No. 2018M630267) and the SUSTech Presidential Postdoctoral Fellowship. Y. Z. acknowledges the China Postdoctoral Science Foundation (2017M622748). H. Y. W. thanks the nancial support from the NRF of Korea (2016M1A2A2940911 and 2015M1A2A2057506).
Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2019
Y1 - 2019
N2 - A new indacenodithiophene-based acceptor-donor-acceptor (A-D-A) type nonfullerene acceptor material ITBTC, featuring a conjugation-extended benzo[b]thiophene-fused end group, was designed and synthesized. Compared to the well known phenyl-fused ITIC acceptor containing a 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC) end group, incorporation of an additional electron-rich thiophene into the IC moiety decreased the electron-accepting strength of the end group and increased the intermolecular interactions of ITBTC molecules. As a result, ITBTC exhibited an elevated lowest unoccupied molecular orbital, an improved electron mobility, and a more favorable blend film morphology. Despite its slightly blue-shifted absorption, the photocurrent of ITBTC-based devices was well-maintained due to the extra absorption band in the short wavelength range, which is induced by its conjugation-extended end group. Benefitting from these characteristics, the ITBTC-based solar cells achieved an enhanced power conversion efficiency (PCE) of 10.99% with a simultaneously improved open-circuit voltage (Voc, 0.94 V) and fill factor (FF, 71.3%) and well-maintained short-circuit current density (Jsc, 16.37 mA cm−2), compared to those of the ITIC-based devices (PCE of 9.53%). These results suggest that extending the π-conjugation of end group through thiophene incorporation is an efficient approach for optimizing both the energy level alignment and intermolecular interaction of the acceptor materials while maintaining their efficient light-harvesting ability. Our study also demonstrates the great potential of the new benzo[b]thiophene-fused end group for constructing high-performance nonfullerene acceptors and provided insight into overcoming the trade-off between Jsc and Voc to realize simultaneously enhanced photovoltaic parameters.
AB - A new indacenodithiophene-based acceptor-donor-acceptor (A-D-A) type nonfullerene acceptor material ITBTC, featuring a conjugation-extended benzo[b]thiophene-fused end group, was designed and synthesized. Compared to the well known phenyl-fused ITIC acceptor containing a 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC) end group, incorporation of an additional electron-rich thiophene into the IC moiety decreased the electron-accepting strength of the end group and increased the intermolecular interactions of ITBTC molecules. As a result, ITBTC exhibited an elevated lowest unoccupied molecular orbital, an improved electron mobility, and a more favorable blend film morphology. Despite its slightly blue-shifted absorption, the photocurrent of ITBTC-based devices was well-maintained due to the extra absorption band in the short wavelength range, which is induced by its conjugation-extended end group. Benefitting from these characteristics, the ITBTC-based solar cells achieved an enhanced power conversion efficiency (PCE) of 10.99% with a simultaneously improved open-circuit voltage (Voc, 0.94 V) and fill factor (FF, 71.3%) and well-maintained short-circuit current density (Jsc, 16.37 mA cm−2), compared to those of the ITIC-based devices (PCE of 9.53%). These results suggest that extending the π-conjugation of end group through thiophene incorporation is an efficient approach for optimizing both the energy level alignment and intermolecular interaction of the acceptor materials while maintaining their efficient light-harvesting ability. Our study also demonstrates the great potential of the new benzo[b]thiophene-fused end group for constructing high-performance nonfullerene acceptors and provided insight into overcoming the trade-off between Jsc and Voc to realize simultaneously enhanced photovoltaic parameters.
UR - http://www.scopus.com/inward/record.url?scp=85064431219&partnerID=8YFLogxK
U2 - 10.1039/c9ta01111k
DO - 10.1039/c9ta01111k
M3 - Article
AN - SCOPUS:85064431219
SN - 2050-7488
VL - 7
SP - 9822
EP - 9830
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 16
ER -