n-Type thiophene semiconductors
View Patent ↗The new fluorocarbon-functionalized and/or heterocycle-modified polythiophenes, in particular, α,ω-diperfluorohexylsexithiophene DFH-6T can be straightforwardly prepared in high yield and purity. Introduction of such modifications to a thiophene core affords enhanced thermal stability and volatility, and increased electron affinity versus the unmodified compositions of the prior art. Evaporated films behave as n-type semiconductors, and can be used to fabricate thin film transistors with FET mobilities ˜0.01 cm 2 /Vs—some of the highest reported to date for n-type organic semiconductors.
1. A method of using thiophene structural modification to promote n-type thiophene conductivity; said method comprising:
preparing a polythiophene composition, said composition comprising a plurality of conjugated thiophene moieties; and
providing said composition a structural modification sufficient to promote n-type conductivity, wherein said structurally modified composition has the structure
wherein R 1 , R 2 and R 3 are selected from the substituent group consisting of fluoroalkyl moieties, C n H 2n+1 and where n is 1 to about 12, H, F and (CH 2 ) a X and where a is 1 to about 12 and X is selected from the group consisting of amino, hydroxy and carboxylic acid functionalities; and x, y and z are integers selected from the group of integers consisting of 1 and integers greater than 1.
2. The method of claim 1 wherein said fluoroalkyl moieties are independently selected from linear, branched and cyclic fluoroalkyl moieties.
3. The method of claim 2 wherein said fluoroalkyl moiety has the compositional formula C n F 2n+1 , where n is 1 to about 8.
4. The method of claim 1 wherein x is 1 to about 4; y is 1 to about 8; and z is 1 to about 12.
5. The method of claim 4 wherein said fluoroalkyl moiety has the compositional formula C n F 2n+1 , where n is 1 to about 8.
6. The method of claim 1 wherein said composition is selected from DFH-4T, DFH-5T, DFH-6T, isoDFH-4T, isoDFH-5T and isoDFH-6T.