TY - JOUR
T1 - Axisymmetric and Asymmetric Naphthalene-Bisthienothiophene Based Nonfullerene Acceptors
T2 - On Constitutional Isomerization and Photovoltaic Performance
AU - Hu, Wei
AU - Du, Xiaoyan
AU - Zhuang, Wenliu
AU - Su, Wenyan
AU - Cao, Jiamin
AU - Pourrahimi, Amir Masoud
AU - Li, Ning
AU - Shen, Xingxing
AU - Zhang, Maojie
AU - Yu, Donghong
AU - Gruber, Wolfgang
AU - Unruh, Tobias
AU - Wang, Ergang
AU - Brabec, Christoph J.
PY - 2020/6/22
Y1 - 2020/6/22
N2 - Two pairs of constitutional isomers of fused-octacyclic nonfullerene acceptors (NFAs) based on a naphthalene-bisthienothiophene core with or without fluorination at the ending groups have been developed. Compared with the axisymmetric NFAs N66-IC and N66-2FIC with two six-member-ring bridges, their asymmetric constitutional isomers N65-IC and N65-2FIC both with one six-member-ring bridge and one five-member-ring bridge exhibit remarkable red-shifted absorption, higher crystallinity, and slightly down-shifted LUMO energy levels. Organic solar cells based on PBDB-T-2F:N65-2FIC achieved a promising power conversion efficiency of 10.19%, which is three times higher than that of its counterpart PBDB-T-2F:N66-2FIC cell (3.46%). While being blended with PBDB-T as the donor material, the asymmetric acceptor analogue N65-IC based solar cell pronounces a PCE of 9.03%, being significantly improved from that of 5.45% for the PBDB-T:N66-IC based cell, which is in consistency with the results from those cells from their both fluorinated donor and acceptor counterparts. Design rules on either both fluorinated, both nonfluorinated, or cross-combined donor/acceptors for device fabrication has been explored. In addition, PBDB-T-2F:N65-2FIC possesses very promising device stability with 85% of its initial PCE after an exposure time of 1500 h under one sun illumination, which is meaningful for their future commercial devices.
AB - Two pairs of constitutional isomers of fused-octacyclic nonfullerene acceptors (NFAs) based on a naphthalene-bisthienothiophene core with or without fluorination at the ending groups have been developed. Compared with the axisymmetric NFAs N66-IC and N66-2FIC with two six-member-ring bridges, their asymmetric constitutional isomers N65-IC and N65-2FIC both with one six-member-ring bridge and one five-member-ring bridge exhibit remarkable red-shifted absorption, higher crystallinity, and slightly down-shifted LUMO energy levels. Organic solar cells based on PBDB-T-2F:N65-2FIC achieved a promising power conversion efficiency of 10.19%, which is three times higher than that of its counterpart PBDB-T-2F:N66-2FIC cell (3.46%). While being blended with PBDB-T as the donor material, the asymmetric acceptor analogue N65-IC based solar cell pronounces a PCE of 9.03%, being significantly improved from that of 5.45% for the PBDB-T:N66-IC based cell, which is in consistency with the results from those cells from their both fluorinated donor and acceptor counterparts. Design rules on either both fluorinated, both nonfluorinated, or cross-combined donor/acceptors for device fabrication has been explored. In addition, PBDB-T-2F:N65-2FIC possesses very promising device stability with 85% of its initial PCE after an exposure time of 1500 h under one sun illumination, which is meaningful for their future commercial devices.
KW - asymmetry
KW - axisymmetry
KW - isomerization
KW - naphthalene
KW - nonfullerene acceptors
KW - organic solar cells
UR - http://www.scopus.com/inward/record.url?scp=85087790030&partnerID=8YFLogxK
U2 - 10.1021/acsaem.0c00689
DO - 10.1021/acsaem.0c00689
M3 - Journal article
AN - SCOPUS:85087790030
SN - 2574-0962
VL - 3
SP - 5734
EP - 5744
JO - ACS Applied Energy Materials
JF - ACS Applied Energy Materials
IS - 6
ER -