Diketopyrrolopyrrole polymer and organic electronic device containing same

Abstract

The present invention relates to a diketopyrrolopyrrole polymer, which is an organic semiconductor compound for an organic electronic device, and a use thereof. The diketopyrrolopyrrole polymer according to the present invention is a novel organic semiconductor compound having high -electron stacking by introducing an electron donor compound, and an organic electronic device employing the same has excellent charge mobility and on/off ratio.

Claims

1. A diketopyrrolopyrrole polymer selected from the group consisting of the following structures: ##STR00019## z is an integer of 6 to 8; and n is an integer of 1 to 1,000.

2. An organic electronic device comprising the diketopyrrolopyrrole polymer of claim 1.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional view illustrating a structure of a general organic thin film transistor composed of a substrate/gate/insulating layer (source, drain)/semiconductor layer (11: substrate, 12: insulating layer, 13: channel material, 14: source, 15: drain, 16: gate).

(2) FIG. 2 illustrates UV-vis absorption spectra of a diketopyrrolopyrrole polymer P-29-DPPDBTE according to Example 4 in a solution state and a film state.

(3) FIG. 3 illustrates UV-vis absorption spectra of a diketopyrrolopyrrole polymer P-29-DPPDTSE according to Example 5 in a solution state and a film state.

(4) FIG. 4 is a graph illustrating electrical properties (cyclic voltammetry) of the diketopyrrolopyrrole polymer P-29-DPPDBTE according to Example 4.

(5) FIG. 5 is a graph illustrating electrical properties (cyclic voltammetry) of the diketopyrrolopyrrole polymer P-29-DPPDTSE according to Example 5.

(6) FIG. 6 is a differential scanning calorimetry (DSC) curve of the diketopyrrolopyrrole polymer P-29-DPPDBTE according to Example 4.

(7) FIG. 7 is a differential scanning calorimetry (DSC) curve of the diketopyrrolopyrrole polymer P-29-DPPDTSE according to Example 5.

(8) FIG. 8 is a thermogravimetric analysis (TGA) curve of the diketopyrrolopyrrole polymer P-29-DPPDBTE according to Example 4.

(9) FIG. 9 is a thermogravimetric analysis (TGA) curve of the diketopyrrolopyrrole polymer P-29-DPPDTSE according to Example 5.

(10) FIGS. 10 and 11 are graphs illustrating properties (transfer curve, output curve) of a device manufactured using a diketopyrrolopyrrole polymer (P-29-DPPDBTE) according to Example 4 by a method of Example 6.

(11) FIGS. 12 and 13 are graphs illustrating properties (transfer curve, output curve) of a device manufactured using a diketopyrrolopyrrole polymer (P-29-DPPDBTE) according to Example 4 by the method of Example 6 after thermal treatment at 200 C.

(12) FIGS. 14 and 15 are graphs illustrating properties (transfer curve, output curve) of a device manufactured using a diketopyrrolopyrrole polymer (P-29-DPPDTSE) according to Example 5 by the method of Example 6.

(13) FIGS. 16 and 17 are graphs illustrating properties (transfer curve, output curve) of a device manufactured using a diketopyrrolopyrrole polymer (P-29-DPPDTSE) according to Example 5 by the method of Example 6 after thermal treatment at 200 C.

BEST MODE

(14) The present invention will be understood and appreciated more fully from the following Examples, and the Examples are for illustrating the present invention and not for limiting the present invention.

EXAMPLE 1

Synthesis of 7-decyl-1-nonadecylbromide

(15) ##STR00014##

(16) A Grignard reagent was prepared by slowly adding 2-decyl-1-tetradecylbromide (30.0 g, 0.072 mol) and magnesium (Mg, 2.40 g, 0.101 mol) to a solvent, tetrahydrofuran (THF, 100 ml), and then, slowly added to a mixed solution of 1,5-dibromopentane (38.0 g, 0.165 mol), copper bromide (CuBr, 0.1 g, 0.72 mmol), and lithium chloride (LiCl, 0.06 g, 1.44 mmol) at 0 C. After reaction at room temperature for 24 hours, the resultant was extracted with a solvent, diethyl ether, dried over magnesium sulfate (MgSO.sub.4), and then, filtered. After removing the solvent, 1,5-dibromopentane was separated using a distiller, and the resultant was purified by column chromatography using hexane as a solvent, thereby obtaining a target compound, 7-decyl-1-nonadecylbromide (28 g, yield: 80%).

(17) .sup.1HNMR (CDCl.sub.3, 300 MHz) [ppm]: 3.76 (d, 2H), 1.88 (d, 2H), 1.4 (s, 1H), 1.26-1.24 (m, 48H), 0.92-0.88 (m, 6H).

EXAMPLE 2

Synthesis of 2,5-bis(2-decylnonadecyl)-3,6-bis(thiophen-2-yl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione

(18) ##STR00015##

(19) After 3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP, 1.00 g, 0.003 mol) and potassium carbonate (K.sub.2CO.sub.3, 1.84 g, 0.012 mol) were put into a flask and dissolved in a solvent, dimethylformamide (DMF, 60 ml), a temperature was raised to 150 C., and the mixture was stirred for 6 hours. In addition, 7-decyl-1-nonadecylbromide (8 g, 0.012 mol) was added thereto in portions, and stirred for 16 hours under nitrogen atmosphere. The resultant was extracted with a solvent, diethyl ether, dried over magnesium sulfate (MgSO.sub.4), and then, filtered. The resultant was separated by column chromatography using hexane/methylene chloride (1:3) as a solvent, thereby obtaining a title compound (1.2 g, yield: 37%).

(20) .sup.1H-NMR (300 MHz, CDCl.sub.3, ppm): 8.96 (d, 2H), 7.64 (d, 2H), 7.32 (d, 2H), 4.11-4.06 (t, 4H), 1.81-1.72 (t, 4H), 1.44-1.27 (m, 98H), 0.92-0.81 (m, 12H), .sup.13C-NMR (125 MHz, CDCl.sub.3, ppm): 161.78, 140.42, 135.62, 130.97, 130.22, 128.98, 108.16, 42.65, 37.82, 34.10, 32.32, 30.55, 30.39, 30.113, 30.054, 29.75, 27.34, 27.12, 27.05, 23.08, 14.49.

EXAMPLE 3

Synthesis of 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-decylnonadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione

(21) ##STR00016##

(22) After 2,5-bis(2-decylnonadecyl)-3,6-bis(thiophen-2-yl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione 1.2 g, 0.85 mmol) was dissolved in chloroform (40 ml) in a flask, light was blocked using aluminum foil, or the like. Thereafter, NBS (0.5 g, 1.75 mmol) was slowly added dropwise thereto and stirred for 8 hours. The resultant was extracted with MC, and an organic layer was washed with water and dried over MgSO.sub.4, followed by removal of a solvent using a rotary evaporator. The resultant was separated by column chromatography using n-hexane/EA (15:1) as a solvent and re-crystallized with MC and hexane, thereby obtaining a title compound (1.2 g, yield: 80%).

(23) .sup.1H-NMR (300 MHz, CDCl.sub.3, ppm): 8.71 (d, 2H), 726 (d, 2H), 4.02-3.97 (t, 4H), 1.78-1.71 (t, 4H), 1.44-1.2 (m, 98H), 0.92-0.87 (m, 12H), .sup.13C-NMR (125 MHz, CDCl.sub.3, ppm): 161.43, 139.38, 135.72, 132.04, 131.56, 119.50, 108.26, 4271, 37.82, 34.09, 3232, 30.56, 30.41, 30.11, 30.05, 29.75, 27.28, 27.12, 27.01, 23.08, 14.49.

EXAMPLE 4

Synthesis of P-29-DPPDBTE

(24) ##STR00017##

(25) P-29-DPPDBTE corresponding to the polymer may be polymerized by a Stille coupling reaction 3,6-bis(5-bromothiophen-2,5-bis(2-decylnonadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (0.50 g, 0.39 mmol) and (E)-1,2-bis(5-(trimethylstannyl)thiophen-2-yl)ethene (0.229 g, 0.39 mmol) were dissolved in chlorobenzene (5 mL), and nitrogen substation was performed. Thereafter, Pd.sub.2(dba).sub.3 (0.007 g, 2 mol %) and P(o-tol).sub.3 (0.011 g, 8 mol %) were added thereto as catalysts, and the mixture was refluxed at 100 C. for 48 hours. Then, the reaction solution was slowly precipitated in methanol (300 mL), and a formed solid was filtered. The filtered solid was purified sequentially with methanol, hexane, toluene, and chloroform through a sohxlet. A dropped liquid was precipitated in methanol again, filtered using a filter, and dried, thereby obtaining a title compound, P-29-DPPDBTE (yield: 90%), as a dark green solid.

(26) 0.52 g. (Mn=33,369, Mw=60,781, PDI=1.82).

(27) .sup.1H NMR (CDCl.sub.3, 500 MHz), (ppm): 8.96 (broad, 4H), 7.1 (broad, 2H), 6.75 (broad, 4H), 4.01 (broad, 4H), 1.25 (broad, 98H), 0.85 (broad, 12H).

EXAMPLE 5

Synthesis of P-29-DPPDTSE

(28) ##STR00018##

(29) P-29-DPPDTSE corresponding to the polymer may be polymerized by a Stille coupling reaction. P-29-DPPDTSE corresponding to a title compound was obtained (yield: 80%) by the same method as in Example 4 except for using 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-decylnonadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (0.500 g, 0.39 mmol), (E)-1,2-bis(5-(trimethylstannyl)selenophen-2-yl)ethene (0.229 g, 0.39 mmol), Pd.sub.2(dba).sub.3 (0.007 g, 2 mol %), and P(o-tol).sub.3 (0.011 g, 8 mol %).

(30) 0.49 g. (Mn=35,826, Mw=58,038, PDI=1.62).

(31) .sup.1H NMR (CDCl.sub.3, 500 MHz), (ppm): 8.78 (broad, 4H), 7.21 (broad, 2H), 6.75 (broad, 4H), 4.02 (broad, 4H), 1.26 (broad, 98H), 0.85 (broad, 12H).

EXAMPLE 6

Manufacturing of Organic Electron Device

(32) An OTFT device was manufactured in a top-contact manner, n-doped silicon (100 nm) was used as a gate, and SiO.sub.2 was used as an insulator. At the time of surface treatment, after a surface was washed using piranha cleaning solution (H.sub.2SO.sub.4:2H.sub.2O.sub.2), self-assemble monolayer (SAM) treatment was performed thereon using octadecyltrichlorosilane (OTS-18, Alfa Corp.). An organic semiconductor layer was coated with chloroform solution (0.2 wt %) at a rate of 2000 rpm for 1 minute using a spin-coater. As an organic semiconductor material, P-29-DPPDBTE and P-29-DPPDTSE synthesized in Examples 4 and 5 were used. Gold used as a source and a drain was deposited at 1 A/s so as to have a thickness of 100 nm. A length of a channel was 15 m and a width thereof was 1500 m. Properties of the OTFT were measured using Keithley 4800.

(33) Charge mobility was obtained from a slope of a graph obtained using (I.sub.SD).sup.1/2 and V.sub.G as variables from the following Saturation Region Current Equation.

(34) $I_{\mathrm{SD}}=\frac{{\mathrm{WC}}_0}{2L}{\left(V_G-V_T\right)}^2$$\sqrt{I_{\mathrm{SD}}}=\sqrt{\frac{{\mathrm{WC}}_0}{2L}}\left(V_G-V_T\right)$$\mathrm{slope}=\sqrt{\frac{{\mathrm{WC}}_0}{2L}}$${}_{\mathrm{FET}}={\left(\mathrm{slope}\right)}^2\frac{2L}{{\mathrm{WC}}_0}$

(35) In Saturation Region Current Equation, I.sub.SD is a source-drain current, or .sub.FET is charge mobility, C.sub.0 is capacitance of an oxide film, W is a width of a channel, L is a length of the channel, V.sub.G is a gate voltage, V.sub.T is a threshold voltage. Further, an off current I.sub.off is a current flowing in an off state. The off current was obtained as a minimum current from a current ratio in an off state.

(36) Light absorption regions of novel diketopyrrolopyrrole polymers (P-29-DPPDBTE and P-29-DPPDTSE) synthesized in Examples 4 and 5 were measured in a solution state and a film state, and the results were illustrated in FIGS. 2 and 3. In order to analyze electrochemical properties of the novel diketopyrrolopyrrole polymers P-29-DPPDBTE and P-29-DPPDTSE), which were organic semiconductor compounds synthesized in Examples 4 and 5, results obtained by measuring electrochemical properties of the novel diketopyrrolopyrrole polymers (P-29-DPPDBTE and P-29-DPPDTSE) at 50 mV/s in a solvent of Bu.sub.4NClO.sub.4 (0.1 molar concentration) using cyclic voltammetry were illustrated in FIGS. 4 and 5. At the time of measurement, a voltage was applied through coating using a carbon electrode.

(37) Optical and electrochemical properties of the diketopyrrolopyrrole polymers (P-29-DPPDBTE and P-29-DPPDTSE) synthesized in Example 4 and Example 5 were illustrated in the following Table 1. Here, HOMO values were values calculated using measurement values in FIGS. 4 and 5. In addition, band gap values were obtained from UV absorption wavelengths in the film state.

(38) TABLE-US-00001 TABLE 1 Electrochemical Properties Optical Properties Band gap UV.sub.max.sup.sol UV.sub.max.sup.film UV-edge (optical) Oxidation E.sub.HOMO Polymer (nm) (nm) (nm) (eV) onset (eV) (eV) P-29-DPPDBTE 802 812 996 1.24 0.85 5.25 (Example 4) P-29-DPPDTSE 822 830 998 1.23 0.87 5.27 (Example 5)

(39) As illustrated in Table 1, the band gap values of the diketopyrrolopyrrole polymers according to the present invention were low, such that charge mobility of the organic electronic devices containing the same was high.

(40) FIGS. 6 and 7 illustrate measurement results using DSC in order to measure thermal stability of the diketopyrrolopyrrole polymers (P-29-DPPDBTE and P-29-DPPDTSE) synthesized in Examples 4 and 5.

(41) FIGS. 8 and 9 illustrate results obtained by measuring decomposition temperatures of the diketopyrrolopyrrole polymers (P-29-DPPDBTE and P-29-DPPDTSE) synthesized in Examples 4 and 5 using TGA.

(42) As illustrated in FIGS. 6 and 7 and FIGS. 8 and 9, it may be appreciated that thermal stability of the organic semiconductor compounds synthesized according to the present invention was excellent, and charge mobility was increased at the time of annealing, such that the organic semiconductor compounds were excellent materials for an organic electronic device.

(43) FIGS. 10 and 11, which are graphs illustrating a transfer curve of the device manufactured in Example 6 using the diketopyrrolopyrrole polymer (P-29-DPPDBTE) synthesized in Example 4, are graphs illustrating properties of the organic electronic device of the polymer material, and

(44) FIGS. 12 and 13, which are graphs illustrating a transfer curve of the device manufactured in Example 6 using the diketopyrrolopyrrole polymer (P-29-DPPDBTE) synthesized in Example 4 after thermal treatment at 200 C., are graphs illustrating properties of the organic electronic device of the polymer material.

(45) In addition, FIGS. 14 and 15, which are graphs illustrating a transfer curve of the device manufactured in Example 6 using the diketopyrrolopyrrole polymer (P-29-DPPDTSE) synthesized in Example 5, are graphs illustrating properties of the organic electronic device of the polymer material, and

(46) FIGS. 16 and 17, which are graphs illustrating a transfer curve of the device manufactured in Example 6 using the diketopyrrolopyrrole polymer (P-29-DPPDTSE) synthesized in Example 5 after thermal treatment at 200 C., are graphs illustrating properties of the organic electronic device of the polymer material.

(47) The properties of the devices manufactured in Example 6 using the diketopyrrolopyrrole polymers (P-29-DPPDBTE and P-29-DPPDTSE) synthesized in Examples 4 and 5 are illustrated in the following Table 2.

(48) TABLE-US-00002 TABLE 2 Thresh- Surface old Thermal Modi- Mobility Voltage On/off Polymer Treatment fication (cm.sup.2/(V s)) (V) Ratio P-29- Room OTS-18 0.52 9.7 7 10.sup.4 DPPDBTE Temperature (Example 4) 180 C. OTS-18 6.32 11.4 8.3 10.sup.4 P-29- Room OTS-18 0.6 6.5 6 10.sup.4 DPPDTSE Temperature (Example 5) 200 C. OTS-18 8.4 8.3 3.1 10.sup.5

(49) As illustrated in Table 2, the organic electronic devices manufactured by the method in Example 6 and thermally treated at 200 C. contained the diketopyrrolopyrrole polymers according to the present invention, thereby having high charge mobility and stable on/off ratios.