ORGANIC ELECTRON TRANSPORT MATERIAL

Abstract

The present invention relates to an organic electron transport material having a compound of the structure shown in formula (I), wherein R1-R4 independently represent hydrogen, C1-C8 substituted or substituted alkyl, C2-C8 substituted or unsubstituted alkenyl, or C2-C8 substituted or unsubstituted alkynyl, the substituents being C1-C4 alkyl or halogen. Device experiments show that an electronic-only organic semiconductor diode device and an organic electroluminescent device manufactured by the organic electron transport material of the present invention have good electron transport performance, high and stable luminance, and a long device life.

Claims

1. An organic electron transport material having a compound of a structure shown in formula (I) ##STR00009## wherein R1-R4 independently represent hydrogen, C1-C8 substituted or substituted alkyl, C2-C8 substituted or unsubstituted alkenyl, or C2-C8 substituted or unsubstituted alkynyl, the substituents being C1-C4 alkyl or halogen.

2. The organic electron transport material according to claim 1, wherein R1-R4 independently represent hydrogen, C1-C4 substituted or substituted alkyl, C2-C4 substituted or unsubstituted alkenyl, or C2-C4 substituted or unsubstituted alkynyl.

3. The organic electron transport material according to claim 2, wherein R1-R4 independently represent hydrogen, or C1-C4 alkyl.

4. The organic electron transport material according to claim 3, wherein R1-R4 are identical.

5. The organic electron transport material according to claim 1, R1-R4 preferably represent hydrogen.

6. The organic electron transport material according to claim 1, having a compound of a structure shown in the following formulas: ##STR00010## ##STR00011##

7. The organic electron transport material according to claim 1, having a compound of a structure shown in the following formula: ##STR00012##

8. An application of the organic electron transport material of any one of claims 1 to 7 in an electronic-only organic semiconductor diode device and an organic electroluminescent device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is an HPLC diagram of a compound 1;

[0022] FIG. 2 is a carbon spectrogram of the compound 1;

[0023] FIG. 3 is a thermogravimetryTGA diagram of the compound 1;

[0024] FIG. 4 is a structural diagram of an electronic-only organic semiconductor diode device according to the present invention, wherein 10 represents a glass substrate, 20 represents an anode, 30 a hole barrier layer, 40 an electron transport layer, 50 an electron injection layer, and 60 a cathode;

[0025] FIG. 5 is a voltage-current density diagram of a device 1 of the present invention;

[0026] FIG. 6 is a voltage-current density diagram of a device 2 of the present invention;

[0027] FIG. 7 is a voltage-current density diagram of devices 3 and 4 of the present invention;

[0028] FIG. 8 is a current density-current efficiency diagram of the devices 3 and 4 of the present invention;

[0029] FIG. 9 is a luminance-color coordinate y diagram of the devices 3 and 4 of the present invention;

[0030] FIG. 10 is an emission spectrum diagram of the devices 3 and 4 of the present invention; and

[0031] FIG. 11 is a structural diagram of an organic electroluminescent device according to the present invention, wherein 10 represents a glass substrate, 20 represents an anode, 30 a hole injection layer, 40 a hole transport layer, 50 a light emitting layer, 60 an electron transport layer, 70 a cathode.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

[0032] In order to describe the present invention in more detail, the following examples are given, but the present invention is not limited to these.

Example 1

[0033] ##STR00004##

Synthesis of Compound 1

[0034] A compound A is synthesized according to the reference document: ACS Macro Letter, 2014, Processes 3, and 10-15. A compound B is synthesized according to the process of reference document: WO 2013182046 A1.

[0035] Reaction delivery: sequentially adding the compound A (2.21 g, 11 mmol), the compound B (7.80 g, 22 mmol), and diphenyl ether (100 mL) to a 250-mL reaction flask; after evacuating hydrogen three times, heating to 260 C., and preserving the heat and reacting for 8 hours till the compound B completely reacts under TLC and HPLC detection, the color of the reaction solution changing from black to yellow during the reaction.

[0036] Treatment after reaction: stopping heating and cooling to 20 C.; adding methanol (100 mL) and stirring for 2 h to separate solid out; washing a filter cake with methanol and drying in vacuum to obtain a crude product; adding ethyl acetate to the crude product and pulping to obtain a yellow compound 1 (4.32 g, yield 46%, HPLC purity 99.0%); performing vacuum sublimation (360 C., 210.sup.5 torr, 8h) to obtain light yellow solid powder with a purity of 99.5%.

[0037] See FIG. 1, the liquid phase conditions are as follows:

[0038] chromatographic column: Inertsil ODS-SP 4.6*250 mm, 5 m, column temperature: 40 C.;

[0039] solvent: DCM, moving phase: ACN, detection wavelength: 254 nm.

[0040] The peak calculation chart is as follows:

TABLE-US-00001 Peak Table Detector A 254 nm Retention Peak No. Compound Time Height Area Area % 1 25.641 228 11458 0.386 2 Product 27.393 50885 2955536 99.576 Y15050703-01 3 33.490 14 1124 0.038 Total 51127 2968119 100.000 .sup.1H NMR (300 MHz, CDCl3) 7.78-7.66 (m, 8H), 7.59-7.46 (m, 6H), 7.43-7.33 (m, 116H), 7.32-7.46 (m, 12H). See FIG. 2.

[0041] The TGA diagram is shown in FIG. 3.

Example 2

Preparation of Electronic-Only Organic Semiconductor Diode Device 1

[0042] The electronic-only organic semiconductor diode device is manufactured by an organic electron transport material of the present invention.

[0043] First, a transparent conductive ITO glass substrate 10 (with an anode 20 on the top) is sequentially washed with a detergent solution and deionized water, ethanol, acetone and deionized water, and then subject to oxygen plasma treatment for 30 seconds.

[0044] Then, BCP which is 5 nm thick is evaporated on ITO as a hole barrier layer 30.

[0045] Then, a compound 1 which is 100 nm thick is evaporated on the hole injection layer as an electron transport layer 40.

[0046] Then, lithium fluoride which is 1 nm thick is evaporated on the electron transport layer as an electron injection layer 50.

[0047] At last, aluminum which is 100 nm thick is evaporated on the electron injection layer as a device cathode 60.

[0048] The structural diagram is as shown in FIG. 4.

[0049] By using the space charge limited current (SCLC), the relationship between the current density and the electric field intensity is as shown in equation (1):

[00001]$\begin{array}{cc}J=\frac{9}{8}.Math.\mathrm{.Math.}.Math..Math.{\mathrm{.Math.}}_0.Math.\frac{E^2}{L}.Math.{}_0.Math.\exp \left(.Math.\sqrt{E}\right)& \left(1\right)\end{array}$

[0050] wherein, J is a current density (mA cm .sup.2), is a relative dielectric constant (it is generally 3 in an organic material), .sub.0 is a vacuum dielectric constant (8.8510.sup.14 C V .sup.1 cm.sup.1), E is an electric field intensity (V cm.sup.1), L is a thickness (cm) of a sample in the device, to is an electric charge mobility (cm.sup.2 V.sup.1 s.sup.1) under zero electric field, and is a Poole-Frenkel factor which indicates how fast the mobility changes with the electric field intensity.

[0051] The structural formula in the device is as follows:

##STR00005##

Comparative Example 1

Preparation of Electronic-Only Organic Semiconductor Diode Device 2

[0052] The method is the same as that of example 2, but the common commercially available compound TmPyPB is used as the electron transport layer 40 to manufacture a comparative electronic-only organic semiconductor diode device.

[0053] The structural formula in the device is as follows:

##STR00006##

Electron Mobility (cm.SUP.2 .V.SUP.1 .s.SUP.1.) of the Manufactured Device

[0054]

TABLE-US-00002 Electron Electron Electron Mobility Mobility Mobility 1 10.sup.5 5 10.sup.5 1 10.sup.6 V/cm Under V/cm Under V/cm Under Device Operating Operating Operating No. o Electric Field Electric Field Electric Field 1 4.74 10.sup.11 1.28 10.sup.9 7.51 10.sup.8 1.59 10.sup.6 2 5.12 10.sup.13 5.81 10.sup.11 2.01 10.sup.8 1.61 10.sup.6

[0055] The electron mobility of the device 1 and the electron mobility of the device 2 under operating electric fields of 110.sup.5 V/cm and 510.sup.5 V/cm are calculated according to formula (1) and data in FIGS. 5 and 6. As can be seen from the results, under operating electric fields of 110.sup.5 V/cm and 510.sup.5 V/cm, the electron mobility of the device 1 is higher than the electron mobility of the device 2; the electron mobility of the device 1 and the electron mobility of the device 2 are almost the same under the operating electric field of 110.sup.6 V/cm, which indicates that the compound 1 has better electron transport property.

Example 3

Preparation of Organic Electroluminescent Device 3

[0056] OLED is manufactured by the organic electronic material of the present invention.

[0057] First, a transparent conductive ITO glass substrate 10 (with an anode 20 on the top) is sequentially washed with a detergent solution and deionized water, ethanol, acetone and deionized water, and then subject to oxygen plasma treatment for 30 seconds.

[0058] Then, a compound C which is 90 nm thick is evaporated on ITO as a hole injection layer 30.

[0059] Then, a compound D is evaporated to form a hole transport layer 40 which is 30 nm thick.

[0060] Then, a compound E (2%) and a compound F (98%) which are 40 nm thick are evaporated on the hole transport layer as a light emitting layer 50.

[0061] Then, the compound 1 (50%) and LiQ (50%) which are 40 nm thick are evaporated on the light emitting layer as an electron transport layer 60.

[0062] At last, Al which is 100 nm thick is taken as a device cathode 70.

[0063] (The structure diagram is as shown in FIG. 11)

Example 4

Preparation of Organic Electroluminescent Device 4

[0064] OLED is manufactured by commercially available materials.

[0065] First, a transparent conductive ITO glass substrate 10 (with an anode 20 on the top) is sequentially washed with a detergent solution and deionized water, ethanol, acetone and deionized water, and then subject to oxygen plasma treatment for 30 seconds.

[0066] Then, a compound C which is 90 nm thick is evaporated on ITO as a hole injection layer 30.

[0067] Then, a compound D is evaporated to form a hole transport layer 40 which is 30 nm thick.

[0068] Then, a compound E (2%) and a compound F (98%) which are 40 nm thick are evaporated on the hole transport layer as a light emitting layer 50.

[0069] Then, the compound G (50%) and LiQ (50%) which are 40 nm thick are evaporated on the light emitting layer as an electron transport layer 60.

[0070] At last, Al which is 100 nm thick is taken as a device cathode 70.

##STR00007## ##STR00008##

[0071] As can be seen from FIGS. 7-8 and from the comparison of the device 3 and the device 4, the electron transport performance of the compound 1 is superior to that of the comparative commercially available compound G

[0072] The followings can be calculated from FIGS. 9-10:

[0073] the manufactured device 3, under an operating current density of 20 mA/cm.sup.2, has a luminance of 7584 cd/m.sup.2, a current efficiency up to 37.9 cd/A, EQE of 11.1 under 14.3 lm/W, as well as a CIEx of 0.3709 and a CIEy of 0.5945 of green light emission.

[0074] the manufactured device 4, under an operating current density of 20 mA/cm.sup.2, has a luminance of 8555 cd/m.sup.2, a current efficiency up to 42.7 cd/A, EQE of 12.4 under 19.5 lm/W, as well as a CIEx of 0.3578 and a CIEy of 0.6061 of green light emission.