N,N′-di(arylalkyl)-substituted naphthalene-based tetracarboxylic diimide compounds as n-type semiconductor materials for thin film transistors
View Patent ↗A thin film transistor comprises a layer of organic semiconductor material comprising a tetracarboxylic diimide naphthalene-based compound having, attached to each of the imide nitrogen atoms, a substituted or unsubstituted arylalkyl moiety. Such transistors can further comprise spaced apart first and second contact means or electrodes in contact with said material. Further disclosed is a process for fabricating an organic thin-film transistor device, preferably by sublimation deposition onto a substrate, wherein the substrate temperature is no more than 100° C.
1. A process for fabricating a thin film semiconductor device, comprising, not necessarily in the following order, the steps of:
(a) depositing, onto a substrate, a thin film of n-channel organic semiconductor material that comprises an N,N′-di(arylalkyl)-substituted-naphthalene tetracarboxylic diimide compound having a substituted or unsubstituted carbocyclic aromatic ring system attached to each imide nitrogen atom through a divalent hydrocarbon group, wherein substituents, if any, on each carbocyclic aromatic ring system are electron donating organic groups, such that the organic semiconductor material exhibits a field effect electron mobility that is greater than 0.01 cm 2 /Vs;
(b) forming a spaced apart source electrode and drain electrode,
wherein the source electrode and the drain electrode are separated by, and electrically connected with, the n-channel semiconductor film; and,
(c) forming a gate electrode spaced apart from the organic semiconductor material,
wherein the N,N′-di(arylalkyl)-substituted-naphthalene tetracarboxylic diimide compound is represented by the following structure:
wherein X is a —CH 2 — or alkyl substituted —CH 2 — divalent group, m is 0, n is 2 or 3, and wherein in said structure, all of R 1 , R 3 , R 4 , R 5 , R 6 , R 8 , R 9 , and R 10 are H, and at least one of R 2 and R 7 is an alkyl group.
2. The process of claim 1 , wherein said compound is deposited on the substrate by sublimation and wherein the substrate has a temperature of no more than 100° C. during deposition.
3. The process of claim 1 wherein there is no prior treatment of interfaces between the electrodes and the thin film of n-channel organic semiconductor material.
4. The process of claim 1 wherein the compound is N,N′-bis[2-methyl-phenylethyl]-naphthalene-1,4,5,8 tetracarboxylic acid diimide, N,N′-bis[3-methyl-phenylethyl]-naphthalene-1,4,5,8 tetracarboxylic acid diimide, or N,N′-bis[2-methyl-phenylmethyl]-naphthalene-1,4,5,8-tetracarboxylic acid diimide or N,N′-bis[3-methyl-phenylmethyl]-naphthalene-1,4,5,8-tetracarboxylic acid diimide or N-(2-methyl-phenylethyl), N′-(phenylethyl)-naphthalene-1,4,5,8-tetracarboxylic acid diimide.
5. The process of claim 1 comprising, not necessarily in order, the following steps:
(a) providing a substrate;
(b) providing a gate electrode material over the substrate
(c) providing a gate dielectric over the gate electrode material;
(d) depositing the thin film of n-channel organic semiconductor material over the gate dielectric:
(e) providing a source electrode and a drain electrode contiguous to the thin film of n-channel organic semiconductor material.
6. The process of claim 5 wherein the steps are performed in the order listed.
7. The process of claim 5 wherein the substrate is flexible.
8. The process of claim 5 carried out in its entirety below a peak temperature of 100° C.
9. An integrated circuit comprising a plurality of thin film transistors made by the process of claim 1 .