Thin film semiconductor comprising a small-molecular semiconducting compound and a non-conductive polymer

Abstract

A thin film semiconductor comprising a compound of formula I or II wherein: R.sup.1 and R.sup.2, at each occurrence, independently are selected from a C.sub.1-30 alkyl group, a C.sub.2-30 alkenyl group, a C.sub.2-30 alkynyl group and a C.sub.1-30 haloalkyl group, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 independently are H or an electron-withdrawing group, wherein at least one of R.sup.3, R.sup.4, R.sup.5, and R.sup.6 is an electron-withdrawing group; and a non-conductive polymer. ##STR00001##

Claims

1. A thin film semiconductor comprising a compound of the following formula I or II: ##STR00006## wherein: R.sup.1 and R.sup.2, at each occurrence, independently are selected from the group consisting of a C.sub.1-30 alkyl group, a C.sub.2-30 alkenyl group, a C.sub.2-30 alkynyl group, and a C.sub.1-30 haloalkyl group, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 independently are H or an electron-withdrawing group, wherein at least one of R.sup.3, R.sup.4, R.sup.5, and R.sup.6 is an electron-withdrawing group; and a non-conductive polymer, wherein the non-conductive polymer is poly(methylmethacrylate), and wherein a weight ratio of the compound of the formula I or II to the non-conductive polymer in the thin film semiconductor is from 5:1 to 1:5.

2. The thin film semiconductor of claim 1, wherein R.sup.1 and R.sup.2, at each occurrence, are selected from the group consisting of a C.sub.1-12 alkyl group and a C.sub.1-12 haloalkyl group.

3. The thin film semiconductor of claim 1, wherein each of R.sup.3, R.sup.4, R.sup.5, and R.sup.6 is selected from the group consisting of H, F, Cl, Br, I, and CN.

4. The thin film semiconductor of claim 1, wherein each of R.sup.3 and R.sup.4 is Br or CN and R.sup.5 and R.sup.6 are H.

5. The thin film semiconductor of claim 1, wherein each of R.sup.3 and R.sup.6 is Br or CN and R.sup.4 and R.sup.5 are H.

6. The thin film semiconductor of claim 1, wherein the compound has the following formula Ia or formula Ib: ##STR00007## wherein R, R are, at each occurrence, selected from the group consisting of a C.sub.1-12 alkyl group and a C.sub.1-12 haloalkyl group, and R.sup.3, R.sup.4, and R.sup.6 are as defined in claim 1.

7. The thin film semiconductor of claim 1, wherein the compound of the formula I is ##STR00008##

8. The thin film semiconductor of claim 1, wherein the compound of formula II is ##STR00009##

9. A solution comprising at least one compound of the following formula I or II: ##STR00010## wherein: R.sup.1 and R.sup.2 each independently, are selected from the group consisting of a C.sub.1-30 alkyl group, a C.sub.2-30 alkenyl group, a C.sub.2-30 alkynyl group, and a C.sub.1-30 haloalkyl group, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 each independently, are H or an electron-withdrawing group, wherein at least one of R.sup.3, R.sup.4, R.sup.5, and R.sup.6 is an electron-withdrawing group, a non-conductive organic polymer, and a solvent, wherein the non-conductive organic polymer is poly(methylmethacrylate), and wherein a weight ratio of the compound of the formula I or II to the non-conductive organic polymer in the solution is from 5:1 to 1:5.

Description

EXAMPLES

Example 1

(1) The semiconductor material, selected from the three example compounds (1)-(3) shown above, was dissolved in typical aromatic solvent such as o-dichlorobenzene (bp=180 C.) or tetralin (bp=206 C.) at a concentration of 0.1 wt.-%. To this solution, 0.1 wt.-% of poly(methylmethacrylate) was added and dissolved.

(2) The glass substrates were treated with a phenyl-substituted silane-based self-assembled mono-layer [trimethoxy(2-phenylethyl)silane, -PTS] to increase the wettability of the solution on the substrate. A syringe pump was used to supply the solution containing the semiconductor and the polymer to the edge of the blade on the substrate at a constant rate. The substrate temperature was kept at 80 C., and the gap between the substrate and the blade was 200 m. The blade was moved slowly in the direction indicated in FIG. 1 at a speed of 30 m/s to grow the thin-film crystals at the edge of the blade.

(3) FIG. 2 shows typical transfer characteristics of the n-type solution crystallized TFT containing the semiconducting compound and PMMA.

(4) FIG. 3 shows the output characteristics of the n-type solution crystallized TFT containing the semiconducting compound and PMMA.

Example 2

(5) Example compound (3) was dissolved in anisole at a concentration of 0.15 wt.-%. To this solution, 0.042 wt.-% of poly(methylmethacrylate) was added and dissolved.

(6) From this solution, a BGTC device was produced. The thin-film crystal layer was fabricated on an SiO.sub.2 treated with -PTS on doped Si by continuous edge-casting as in Example 1 while keeping the solution and substrate temperature at 100 C. The device characterization indicated that the electron mobility is 0.28 cm.sup.2/Vs and the threshold voltage is 4.2 V.