Organic electroluminescent transistor
The present teachings relate to an organic electroluminescent transistor with improved light-emission characteristics. More specifically, the present organic electroluminescent transistor has an emissive ambipolar channel including at least one layer of an n-type semiconductor material, at least one layer of a p-type semiconductor material, and at least one layer of an emissive material arranged between the layers of the p-type and n-type semiconductor materials, where the multilayer emissive ambipolar channel includes, among various layers, a layer of a p-type semiconductor material comprising a benzothieno-benzothiophene compound, and/or a layer of an emissive material comprising a blend material that includes an organic carbazole derivative as the host matrix compound and an iridium complex as the guest emitter.
1. An organic electroluminescent transistor comprising: at least one dielectric layer; at least one control electrode; at least one drain electrode; at least one source electrode; and an assembly comprising an emissive ambipolar channel, wherein:
said dielectric layer is arranged between said control electrode and said assembly;
said emissive ambipolar channel comprises at least one layer of an n-type semiconductor material, at least one layer of a p-type semiconductor material, and at least one layer of an emissive material arranged between said layers of p-type and n-type semiconductor materials, the emissive material including a fluorescent or phosphorescent emitter;
said p-type semiconductor material comprises a benzothieno-benzothiophene compound of formula (P-I)
wherein R a and R b are independently selected from the group consisting of H, a C 1-18 alkyl group, and a C 6-14 aryl group;
said n-type semiconductor material comprises a bis(p-fluoroalkyl)phenyl-substituted oligomeric thiophene compound, wherein the oligomeric thiophene compound has 2, 3, 4, 5 or 6 thiophene moieties; and
said emissive material comprises a blend material comprising an organic carbazole derivative as a host matrix compound and an iridium complex as a guest emitter.
2. The organic electroluminescent transistor according to claim 1 , wherein said p-type semiconductor material comprises a benzothieno-benzothiophene compound of formula
3. The organic electroluminescent transistor according to claim 1 where said p-type semiconductor material comprises a benzothieno-benzothiophene compound of formula
4. The organic electroluminescent transistor according to claim 2 , wherein R a and R b are identical linear C 3-12 alkyl groups.
5. The organic electroluminescent transistor according to claim 1 , wherein said p-type semiconductor material comprises a compound of the formula
wherein each R is a phenyl group.
6. The organic electroluminescent transistor according to claim 1 , wherein two or more of the thiophene moieties of the bis(p-fluoroalkyl)phenyl-substituted oligomeric thiophene compound are fused.
7. The organic electroluminescent transistor according to claim 6 , wherein the bis(p-fluoroalkyl)phenyl-substituted oligomeric thiophene compound is a thienothiophene having the structural formula
wherein Ar and Ar′ are phenyl, m and m′ are 1, and R 1 and R 2 are independently fluoroalkyl.
8. The organic electroluminescent transistor according to claim 1 , wherein the thickness of said layer of p-type semiconductor material is between 5 and 50 nm.
9. The organic electroluminescent transistor according to claim 1 , characterized in that the thickness of said layer of n-type semiconductor material is between 30 nm and 60 nm.
10. The organic electroluminescent transistor according to claim 9 , wherein the thickness of said layer of p-type semiconductor material is between 15 and 45 nm.
11. The organic electroluminescent transistor according to claim 1 , characterized in that said layer of emissive material has a thickness between 30 nm and 60 nm.
12. The organic electroluminescent transistor according to claim 1 , wherein the organic carbazole derivative and the iridium complex are selected from the group consisting of:
13. The organic electroluminescent transistor according to claim 1 , wherein said source electrode is in contact with said layer of p-type semiconductor material and said drain electrode is in contact with said layer of n-type semiconductor material.
14. The organic electroluminescent transistor according to claim 1 , wherein said source electrode and said drain electrode are composed of at least one different material.
15. The organic electroluminescent transistor according to claim 1 , wherein an injection sublayer is interposed between said source electrode and the layer of p-type or n-type semiconductor material and/or an injection sublayer is interposed between said drain electrode and the layer of the p-type or n-type semiconductor material.
16. The organic electroluminescent transistor according to claim 1 , wherein each of the control electrode, drain electrode, and source electrode independently comprises a metal or a transparent conducting oxide selected from the group consisting of gold, silver, molybdenum, copper, titanium, chromium, tin-doped indium oxide and combination thereof.
17. The organic electroluminescent transistor according to claim 1 , wherein the dielectric layer comprises an electrically insulating material selected from the group consisting of an inorganic oxide or nitride, a molecular dielectric, a polymeric dielectric, and combination thereof.
18. The organic electroluminescent transistor according to claim 17 , wherein the inorganic oxide or nitride is selected from the group consisting of SiO 2 , Si 3 N 4 , Al 2 O 3 , ZrO x , Al-doped ZrO x , and HfO x .
19. The organic electroluminescent transistor according to claim 1 , further comprising a passivation layer covering a top surface of the emissive ambipolar channel.
20. An optoelectronic device for producing an image, the optoelectronic device comprising a plurality of identical or different organic electroluminescent transistors according to claim 1 , interconnected to each other and deposited on a substrate.