Organic thin film transistor
Organic thin film transistors with improved mobility are disclosed. The semiconducting layer comprises a semiconductor material of Formula (I): wherein R 1 and R 2 are independently selected from alkyl, substituted alkyl, aryl, and substituted aryl; and R 3 and R 4 are independently selected from hydrogen, alkyl, substituted alkyl, aryl, and substituted aryl. A silanized interfacial layer is also present which has alkyl sidechains extending from its surface towards the semiconducting layer.
1. A thin film transistor comprising a dielectric layer, an interfacial layer, and a semiconducting layer;
wherein the interfacial layer is between the dielectric layer and the semiconducting layer;
wherein the interfacial layer is formed from a silane of Formula (II):
and wherein the semiconducting layer comprises a semiconductor of Formula (I):
wherein R 1 , R 2 , R 3 , R 4 , and R′ are identical to each other and are straight chain alkyl having from about 8 to about 18 carbon atoms; wherein R″ is alkyl having from about 1 to about 24 carbon atoms, halogen, alkoxy, hydroxyl, or amino; wherein L is halogen, oxygen, alkoxy, hydroxyl, or amino; wherein k is 1 or 2; and wherein m is an integer from 1 to 3.
2. The transistor of claim 1 , wherein the silane is selected from the group consisting of (i) hexamethyldisilazane and (ii) a silane of the formula R′SiX 3 , wherein R is alkyl having from about 8 to about 18 carbon atoms, and X is halogen.
3. The transistor of claim 2 , wherein R′ is C 12 H 25 and X is chlorine.
4. The transistor of claim 1 , wherein R′ is alkyl having about 12 carbon atoms.
5. The transistor of claim 1 , wherein R′, R 1 , R 2 , R 3 , and R 4 are C 12 H 25 .
6. The transistor of claim 5 , wherein the interfacial layer is formed from dodecyltrichlorosilane.
7. The transistor of claim 6 , wherein the interfacial layer is a self-assembled monolayer of dodecyltrichlorosilane.
8. The transistor of claim 6 , wherein the interfacial layer is a self-assembled multilayer of dodecyltrichlorosilane.
9. The transistor of claim 1 , wherein the transistor has a mobility of 0.1 cm 2 /V·sec or more.
10. The transistor of claim 1 , wherein the transistor has a mobility of 0.25 cm 2 /V·sec or more.
11. The thin film transistor of claim 1 ; wherein the interfacial layer is formed from an aged silane solution containing the silane, the silane solution being aged at a relative humidity of from about 30% to 80% at a temperature of from about 25° C. to about 80° C. for from about 10 minutes to about 60 minutes, the silane solution then being used to form the interfacial layer.
12. A thin-film transistor, comprising:
a gate electrode, a source electrode, a drain electrode, a dielectric layer, an interfacial layer, and a semiconducting layer;
wherein the interfacial layer is located between the dielectric layer and the semiconducting layer;
wherein the dielectric layer is located between the gate electrode and the semiconducting layer;
wherein the interfacial layer is formed from a silane of the formula C 12 H 25 SiX 3 , where X is selected from Cl, OCH 3 , and mixtures thereof; and
wherein the semiconducting layer comprises a semiconductor of Formula (I):
wherein R 1 , R 2 , R 3 , and R 4 are —C 12 H 25 .
13. The Thin Film Transistor of claim 12 ; wherein the interfacial layer is formed from an aged silane solution containing the silane, the silane solution being aged at a relative humidity of from about 30% to 80% at a temperature of from about 25° C. to about 80° C. for from about 10 minutes to about 60 minutes, the silane solution then being used to form the interfacial layer.