Macrocyclization in the Design of Organic n-Type Electronic Materials.
Here, we compare analogous cyclic and acyclic π-conjugated molecules as n-type electronic materials and find that the cyclic molecules have numerous benefits in organic photovoltaics. This is the first report of such a direct comparison. We designed two conjugated cycles for this study. Each comprises four subunits: one combines four electron-accepting, redox-active, diphenyl-perylenediimide subunits, and the other alternates two electron-donating bithiophene units with two diphenyl-perylenediimide units. We compare the macrocycles to acyclic versions of these molecules and find that, relative to the acyclic analogs, the conjugated macrocycles have bathochromically shifted UV-vis absorbances and are more easily reduced. In blended films, macrocycle-based devices show higher electron mobility and good morphology. All of these factors contribute to the more than doubling of the power conversion efficiency observed in organic photovoltaic devices with these macrocycles as the n-type, electron transporting material. This study highlights the importance of geometric design in creating new molecular semiconductors. The ease with which we can design and tune the electronic properties of these cyclic structures charts a clear path to creating a new family of cyclic, conjugated molecules as electron transporting materials in optoelectronic and electronic devices.
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Melissa
M
Ball
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Yu
Y
Zhong
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Brandon
B
Fowler
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Boyuan
B
Zhang
Department of Chemistry, Columbia University , New York, New York 10027, United States.|The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University , Shanghai, China 200234.
Panpan
P
Li
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Grisha
G
Etkin
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Daniel W
DW
Paley
Department of Chemistry, Columbia University , New York, New York 10027, United States.
John
J
Decatur
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Ankur K
AK
Dalsania
The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University , Shanghai, China 200234.
Hexing
H
Li
The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University , Shanghai, China 200234.
Shengxiong
S
Xiao
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Fay
F
Ng
Department of Chemistry, Columbia University , New York, New York 10027, United States.
Michael L
ML
Steigerwald
Department of Chemistry, Columbia University , New York, New York 10027, United States.|The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Optoelectronic Nano Materials and Devices Institute, Department of Chemistry, Shanghai Normal University , Shanghai, China 200234.
Colin
C
Nuckolls