Liquid-crystalline semiconducting copolymers with intramolecular donor-acceptor building blocks for high-stability polymer transistors.
The ability to control the molecular organization of electronically active liquid-crystalline polymer semiconductors on surfaces provides opportunities to develop easy-to-process yet highly ordered supramolecular systems and, in particular, to optimize their electrical and environmental reliability in applications in the field of large-area printed electronics and photovoltaics. Understanding the relationship between liquid-crystalline nanostructure and electrical stability on appropriate molecular surfaces is the key to enhancing the performance of organic field-effect transistors (OFETs) to a degree comparable to that of amorphous silicon (a-Si). Here, we report a novel donor-acceptor type liquid-crystalline semiconducting copolymer, poly(didodecylquaterthiophene-alt-didodecylbithiazole), which contains both electron-donating quaterthiophene and electron-accepting 5,5'-bithiazole units. This copolymer exhibits excellent electrical characteristics such as field-effect mobilities as high as 0.33 cm(2)/V.s and good bias-stress stability comparable to that of amorphous silicon (a-Si). Liquid-crystalline thin films with structural anisotropy form spontaneously through self-organization of individual polymer chains as a result of intermolecular interactions in the liquid-crystalline mesophase. These thin films adopt preferential well-ordered intermolecular pi-pi stacking parallel to the substrate surface. This bottom-up assembly of the liquid-crystalline semiconducting copolymer enables facile fabrication of highly ordered channel layers with remarkable electrical stability.
Kim
Do Hwan
DH
Display Laboratory, Materials and Device Institute, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Yongin 446-712, Korea.
Lee
Bang-Lin
BL
Moon
Hyunsik
H
Kang
Hee Min
HM
Jeong
Eun Jeong
EJ
Park
Jeong-Il
JI
Han
Kuk-Min
KM
Lee
Sangyoon
S
Yoo
Byung Wook
BW
Koo
Bon Won
BW
Kim
Joo Young
JY
Lee
Wi Hyoung
WH
Cho
Kilwon
K
Becerril
Hector Alejandro
HA
Bao
Zhenan
Z
D046911:Macromolecular Substances / Q000737:chemistry; D015394:Molecular Structure; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D012666:Semiconductors; D013499:Surface Properties; D014173:Transistors, Electronic
D046911:Macromolecular Substances; D011108:Polymers; C422409:liquid crystal polymer