Fluorocarbon-modified organic semiconductors: molecular architecture, electronic, and crystal structure tuning of arene- versus fluoroarene-thiophene oligomer thin-film properties.
We present here the systematic synthesis and comparative physicochemical characterization of a series of regiochemically varied and core size extension-modulated arene(perfluoroarene)-thiophene oligomers. The molecules investigated are: 5,5''-diphenyl-2,2':5',2'':5'',2'''-quaterthiophene (1), 5,5'-bis[1-[4-(thien-2-yl)phenyl]]-2,2'-dithiophene (2), 4,4'-bis[5-(2,2'-dithiophenyl)]-biphenyl (3), 5,5''-diperfluorophenyl-2,2':5',2'':5'',2'''-quaterthiophene (4), 5,5'-bis[1-[4-(thien-2-yl)perfluorophenyl]]-2,2'-dithiophene (5), 4,4'-bis[5-(2,2'-dithiophenyl)]-perfluorobiphenyl (6), 5,5''-diperfluorophenyl-2,2':5',2''-tertthiophene (7), 5,5'-diperfluorophenyl-2,2'-dihiophene (8), and 5,5-diperfluorophenylthiophene (9). Trends in optical absorption and emission parameters, molecular structures as defined by single-crystal X-ray diffraction, as well as electrochemical redox processes are described. The morphologies and microstructures of the vapor-deposited films grown over a range of growth temperatures have also been characterized. Field-effect transistor (FET) measurements demonstrate that all of these materials are FET-active and, depending on the molecular architecture, exhibit comparably good p- or n-type mobility when optimum film microstructural order is achieved. A very large n-channel mobility of approximately 0.5 cm2/Vs with I(on)/I(off) ratios > 10(8) is achieved for films of 4.
Yoon
Myung-Han
MH
Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Facchetti
Antonio
A
Stern
Charlotte E
CE
Marks
Tobin J
TJ
D018360:Crystallography, X-Ray; D005466:Fluorocarbons / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry; D012666:Semiconductors
D005466:Fluorocarbons; D011108:Polymers