Hybrid ambipolar TFTs
The present invention relates inter alia to an electronic device, preferably a thin film transistor (TFT) comprising layers with n-type and p-type semi conducting materials, wherein the p-type layer comprises at least one organic hole transport material. Furthermore, the present invention relates to the use of the electronic device according to the invention in an electronic equipment selected from an RFID and backplanes for a display, electronic book and electronic paper, and an electronic equipment comprising an electronic device according to the invention.
1. An electronic device comprising arranged on a substrate ( 5 ):
(a) a semiconductor body comprising a layer ( 1 ) which is either a n-type or a p-type layer, and a layer ( 2 ), which is either a n-type or a p-type layer, wherein one of both layers ( 1 ) and ( 2 ) is a n-type and the other one a p-type layer in which the p-type layer (( 1 ) or ( 2 )) comprises at least one organic hole transport material (HTM); and
(b) a first electrode ( 4 ); and
(c) an insulating layer A ( 6 ) interposed between the semiconductor body and the first electrode;
(d) a second electrode ( 3 ) which is in contact with the semiconductor body; and
(e) a third electrode ( 7 ) which is in contact with the semiconductor body but is detached from the second electrode;
characterized in that
(1) the n-type layer comprises an inorganic n-type semiconductor material and the said at least one organic hole transport material has a lowest unoccupied molecule orbital (LUMO) at an energy level higher than −2.7 eV; and/or
(2) the semiconductor body further comprises an insulating layer B ( 8 ) interposed between the n-type layer and the p-type layer.
2. Electronic device according to claim 1 , characterized in that the organic p-type layer and/or the organic n-type layer is coated from solution.
3. Electronic device according to claim 1 , characterized in that the n-type layer comprises an inorganic n-type semiconductor material.
4. Electronic device according to claim 3 , characterized in that the inorganic n-type semiconductor material is selected from metal oxides, group IV, group III-V, group IV-VI and group II-VI semiconductors.
5. Electronic device according to claim 3 , characterized in that the inorganic n-type semiconductor material is a metal oxide, which is selected from ZnO, In 2 O 3 , SnO 2 , TiO 2 , Ga 2 O 3 , MoO 3 and an alloy or a mixture thereof.
6. Electronic device according to claim 3 , characterized in that the inorganic n-type layer is formed by coating a precursor compound of the metal oxide on the substrate and heating the precursor to obtain a film of the metal oxide on the substrate.
7. Electronic device according to claim 1 , characterized in that the thickness of the n-type layer is in the range of 1 to 200 nm.
8. Electronic device according to claim 1 , characterized in that the organic p-type material comprises a group selected from amines, triaryl amines, thiophenes, carbazoles, indenocarbazoles, indolocarbazoles, phthalocyanines, porphyrines and derivatives thereof.
9. Electronic device according to claim 1 , characterized in that the insulating layer B ( 8 ) comprises materials having a dielectric constant in the range of from 1.0 to 5.0.
10. Electronic device according to claim 1 , characterized in that the insulating layer B ( 8 ) comprises a fluoropolymer, a perfluoropolymer and/or a metal oxide.
11. Electronic device according to claim 10 , characterized in that the metal oxide is selected from the group consisting of SiO x , SiN x , AlO x , ZrO x , HfO x , TiO x , wherein x is an integer between 1 and 4.
12. Electronic device according to claim 1 , characterized in that the thickness of the insulating layer B ( 8 ) is in the range of 1 nm to 1 μm.
13. An electronic equipment selected from an RFID and backplane for a display comprising an electronic device of claim 1 .
14. Electronic equipment comprising an electronic device according to claim 1 .