KR101500325B1 - platinum complex with 1,10-phenanthroline derivatives and organic light emitting diode containing the same - Google Patents

Abstract

The present invention relates to a platinum complex containing 1,10-phenanthroline and an organic light-emitting device containing such a platinum complex. The organic light-emitting device employing the platinum complex according to the present invention has high luminous efficiency and low power consumption .

Description

Platinum Complexes Containing 1,10-Phenanthroline Derivatives and Organic Light-Emitting Devices Containing the Platinum Complexes [0002]

The present invention relates to a novel platinum complex and an organic light emitting device including the same. More particularly, the present invention relates to a dopant compound that can be used for a light emitting layer of an organic light emitting device, and includes a 1,10-phenanthroline derivative as a platinum complex for a phosphorescent material And an organic light emitting device containing the platinum complex.

The organic light emitting device was first found in an anthracene single crystal, which is one of the organic materials, and the charge transport mechanism and the electroluminescence characteristics in the organic material have been studied. However, the efficiency and lifetime of the device are very low.

After that, tris-8-hydroxyquinolonato aluminum (Alq ₃ ) and (N, N'-diphenyl-N, N'-bis [3-methyl] -1,1'-biphenyl -4,4'-diamine, TPD), and a green light emitting device improved in efficiency and stability was prepared.

However, these organic light emitting devices have advantages such as a low driving voltage and a thin film material close to 100 nm, but they have disadvantages such as low stability to heat and molecular rearrangement (or deterioration) Efforts have been made to develop OLED displays using low molecular weight materials.

In 1990, it was reported in Nature that it is possible to fabricate an organic light emitting diode (OLED) as a passive polymer. In other words, PPV (p-phenylenevinylene), which is applied to polymer OLED, is a type in which electrons are co-nucleated and electrons are not localized by any chemical bonds, It is possible to move relatively freely, and it has been found that it is a material suitable for showing luminescence characteristics in the presence of an electric field by exhibiting semiconductor properties. In 1998, Princeton University in the United States developed a phosphorescent organic EL that can utilize 100% of excitons formed by recombination of Pt (OEP) and Ir (ppy) ₃ . (blue) color organic light emitting devices have been actively studied.

Ruthenium, iridium, platinum, europium, terbium, etc. are widely used in the development of phosphorescent materials, and it has been reported that phosphorescence can be efficiently obtained even at room temperature by using iridium or platinum complex having high atomic number Studies on iridium or platinum have been actively conducted (Korean Patent Publication No. 2012-0038319).

If heavy metals such as ruthenium, iridium, and platinum are introduced, the complex will have singlet state ( ¹ MLCT) and triple state ( ³ MLCT) through spin-orbital coupling, This is because the inhibited transition is possible when mixed, and phosphorescence may occur effectively at room temperature. In particular, spin-orbit coupling is proportional to the fourth power of the atomic number, so heavy atomic complexes such as iridium and platinum are known to have high phosphorescent efficiency.

In addition, since it is known that the metal compound having a luminescence property changes not only in the metal itself but also in a substance (ligand) coordinated to the metal, the binding of an effective ligand of the metal complex is very important It is one.

On the other hand, a paraphenylvinylidene (PPV) based polymer material is mainly used as a host material, which is a polymer light emitting material, in a light emitting layer of an organic light emitting device, and a heavy metal complex compound is used as a dopant material in order to increase light emitting efficiency.

The inexpensive process for manufacturing the organic light emitting device is a spin coating method. The dopant material is dissolved in the organic solvent and mixed uniformly with the host polymer material, thereby improving the luminous efficiency.

However, since most organic light emitting devices using phosphorescence are limited to red and green luminescence at present, their application range to a color display is narrow, light emission characteristics can be improved for other colors, light emission wavelength can be controlled, Development of such an excellent compound for a phosphorescent material has been desired.

Korean Patent Publication No. 2012-0038319 (Publication date: April 23, 2012)

The present invention provides platinum complexes containing 1,10-phenanthroline derivatives which can have high luminous efficiency and low power consumption even at high luminance.

The present invention also provides an organic light emitting device containing a platinum complex containing a 1,10-phenanthroline derivative of the present invention and having excellent internal quantum efficiency.

The present invention relates to a platinum complex having excellent luminescence properties and an organic light emitting device containing the platinum complex. More particularly, the present invention relates to a platinum complex having excellent luminescence properties, And an organic light emitting device including the platinum complex.

[Chemical Formula 1]

(In the formula 1,

R ₁ to R ₅ are independently hydrogen, halogen, C ₁ -C ₂₀ alkyl, C ₂ -C ₂₀ alkenyl, C ₂ -C ₂₀ alkynyl or a C ₁ -C ₂₀ alkoxy, wherein R ₁ to R ₅ each other, Alkyl, alkenyl, alkynyl and alkoxy may be further substituted with halogen, cyano or nitro;

Wherein R is hydrogen, C ₁ -C ₂₀ alkyl, C ₂ -C ₂₀ alkenyl, C ₂ -C ₂₀ alkynyl or C ₁ -C ₂₀ alkoxy, wherein the alkyl, alkenyl, alkynyl and alkoxy of R are independently selected from halogen, Cyano, nitro, C ₁ -C ₂₀ alkyl or C ₆ -C ₂₀ aryl;

o is an integer from 1 to 5;

p is an integer from 1 to 4;

q is an integer of 1 to 2, and when o, p and q are 2 or more, R ₁ to R ₅ and R may be the same or different from each other.

)가 가지는 이중결합으로 인해 낮은 에너지로도 본 발명의 백금 착체의 전자를 들뜨게 하여 빛을 발광하므로 단파장(blue)에서 우수한 발광특성을 가진다.In the platinum complex of the present invention, electron-rich nitrogen atoms are present around the central metal platinum, and the main ligand, 1,10-phenanthroline derivative, and the auxiliary ligand

), The electrons of the platinum complex of the present invention are excited by a low energy to emit light, and thus have excellent light emission characteristics in a short wavelength.

That is, due to the carbon-carbon double bonds of the main electron and the secondary electron and the secondary electron and the secondary electrons of the main and auxiliary ligands, they are easily excited at the wavelength of light having a low energy, Is very high.

In the general formula (1), R is independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, At least one substituent selected from the group consisting of a halogen atom, a cyano group, a cyano group, a trifluoromethyl group and a mercapto group may be substituted with at least one substituent selected from the group consisting of a halogen atom, a cyano group, a cyano group, a cyano group, Lt; / RTI >

In the above formula (1), R has a high electron density at the bottom state, but when excited by energy from the outside, the electron density moves to the center metal and the external quantum efficiency increases. In this respect R is a C ₂ -C ₂₀ alkenyl or C ₂ -C ₂₀ alkynyl having a higher electron density is preferred.

Preferably, R ₁ to R ₅ in the formula (1) according to an embodiment of the present invention are hydrogen, C ₁ -C ₂₀ alkyl or halogen, R is C ₁ -C ₂₀ alkyl, C ₂ -C ₂₀ Or C ₂ -C ₂₀ alkynyl, more preferably C ₂ -C ₂₀ alkenyl substituted with phenyl.

The platinum complex represented by Formula 1 according to an embodiment of the present invention may be represented by Formula 2 below.

(2)

(In the formula (2)

R ₁ to R ₅ are hydrogen or C ₁ -C ₂₀ alkyl;

p is an integer from 1 to 4;

and q is an integer of 1 to 2.)

Specifically, in Formula 2, R ₁ to R ₅ independently represent hydrogen, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, Propyl group or a tert-butyl group.

The platinum complex represented by the general formula (2) has a vinyl group substituted by phenyl as an auxiliary ligand, that is, a phenylvinyl group, thereby enhancing the luminous efficiency of the organic light emitting device including the same.

That is, when the vinyl group has a high electron density, the electron moves to the center metal Pt and has a high quantum efficiency, and the emission wavelength shifts to the short wavelength side and moves toward the blue series.

More specifically, the platinum complex containing the 1,10-phenanthroline derivative of the present invention can be selected from the following structures, but is not limited thereto.

The substituents comprising " alkyl ", " alkoxy " and other " alkyl " moieties described in this invention encompass both linear and branched forms. The term " aryl " in the present invention means an organic radical derived from an aromatic hydrocarbon by the removal of one hydrogen, and may be a single or fused ring containing 4 to 7, preferably 5 or 6 ring atoms, A ring system, and a form in which a plurality of aryls are connected by a single bond. Specific examples include, but are not limited to, phenyl, naphthyl, biphenyl, anthryl, indenyl, fluorenyl, and the like.

The maximum phosphorescence emission wavelength (? Max, maximum emission maximum wavelength) of the platinum complex according to an embodiment of the present invention may be 350 to 600 nm, more preferably 350 to 450 nm, and the internal phosphorescent efficiency may be 80 to 100% / Pt < - > atom.

Platinum complexes containing the 1,10-phenanthroline derivative represented by formula (1) of the present invention can be prepared by the following reaction formula.

[Reaction Scheme]

Wherein R ₁ to R ₅ , R, o, p and q are the same as defined in the above formula (1), and X is halogen.

In the above production process, the reaction temperature is usually 40 to 120 ° C, and the reaction rate is preferably 60 to 100 ° C, more preferably 90 to 100 ° C. The reaction time varies depending on the reaction temperature, the solvent, and the reaction conditions depending on the addition, but is usually carried out in the range of 30 minutes to 5 hours, preferably 1 hour to 4 hours, more preferably 1 hour to 3 hours.

The platinum complex precursor used for preparing the compound of the present invention is selected from an inorganic platinum compound and an organic platinum complex. Preferred examples of the inorganic platinum compound include platinum halides such as platinum chloride, platinum bromide and platinum iodide, and halogenated platinates such as sodium chloride, potassium chloride, potassium bromide and potassium iodide. Platinum chloride and potassium chloroplatinic acid are more preferred because of the availability of water.

The present invention also provides an organic electroluminescent device comprising a platinum complex containing a 1,10-phenanthroline derivative of the present invention.

The platinum complex comprising the 1,10-phenanthroline derivative having the skeleton structure of Formula 1 prepared in the present invention is a novel platinum complex which is an organic luminescent dopant and has a luminescent property and a luminescent property .

Therefore, a platinum complex containing a 1,10-phenanthroline derivative having a skeleton structure of Formula (1) can be usefully used as a phosphorescent material of an organic light emitting device having an excellent luminous efficiency.

The platinum complex containing the 1,10-phenanthroline derivative of the present invention is a substituent having a high electron density in the main ligand and the auxiliary ligand, more specifically, 1, 10-phenanthroline as the main ligand, and an electron density A bipyridinyl group having a high substituent, especially a phenylvinyl group, is introduced to have excellent luminescent properties.

Further, the organic light emitting device including the platinum complex including the 1,10-phenanthroline derivative of the present invention has high internal quantum efficiency and high luminescence characteristics even at high luminance.

1 shows an absorption spectrum (a CH ₂ Cl ₂ solvent) of a platinum complex containing a 1,10-phenanthroline derivative synthesized in Example 1 of the present invention,
2 shows the luminescence spectrum (CH ₂ Cl ₂ solvent) of the platinum complex containing the 1,10-phenanthroline derivative synthesized in Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, it is not intended to limit the scope of the present invention.

Example 1 Synthesis of Pt (4- (N, N-bis (pyridyl) amino) stilbene) (1,10-Phenanthroline)

After removing the argon and vacuum three times to remove oxygen and water present in the 100cc Schlenk tube, Pt (4- (N, N-bis (pyridyl) amino) stilbene) Cl ₂ 60 mg, 0.0975 mmol). To this was added 1,10-Phenanthroline (17.57 mg, 0.0975 mmol) dissolved in CH ₂ Cl ₂ (5 ml).

The Schlenk tube containing the reaction mixture was refluxed at 95 ° C for 2 hours under argon gas atmosphere. After confirming the completion of the reaction, the mixture was cooled at room temperature. Filtration was performed to remove the resulting precipitate. H ₂ O (40 ml) was added to the supernatant obtained by filtration, and then, using CH ₂ Cl ₂ And extracted. The extracted mixture was vacuum-dried to obtain the title compound (yield: 67%).

^{1 H-NMR (400MHz, dmso} -d 6 /ppm):9.10(t, 2H), 8.97 (dt, 2H), 8.50 (dd, 2H), 8.11 (td, 2H), 8.00 (s, 2H), 2H), 7.45 (d, 2H), 7.85 (m, 2H), 7.85 (d, (s, 2 H) 7.31 (dd, 1 H)

¹³ C-NMR (400 MHz, dmso-d ₆ / ppm): 153.36,151.7,149.48,146.09,142.62,137.50,135.87,129.96,129.73,128.95,128.41,127.94,127.21,126.37,125.64,124.61,121.0,115.0 , 113.30, 108.9

[Example 2] Measurement of luminescence property of mononuclear platinum complex

To investigate the luminescence properties, the binuclear complex synthesized in Example 1 was dissolved in CH ₂ Cl ₂ of 5 × 10 ^-5 M and the apparatus used was JASCO FP-6500. The excitation wavelength of the complex was based on the absorption wavelength. Based on the measured data, the luminous efficiencies of the complexes were calculated according to the following formula (1), and the results are shown in Table 1 below. As a comparative example, a platinum complex ((4,4'-di-tert-butyl-2,2'-bipyridine) Pt (bis (phenylethynyl) (Mehdi Rashidi, The reference luminescent material used in the present invention is [Ru (bpy) ₃ ] ^2+, and the internal quantum efficiency is 0.062 (bpy) _3. to be.

[Comparative Example Structure]

[Equation 1]

? _S = (A _std / A _s ) (I _s / I _std )? _Std

[In the above formula, A _std : UV absorption coefficient of the [Ru (bpy) ₃ ] ²⁺ complex as a standard material

A _s : UV absorption coefficient of the SAMPL complex

I _s : intensity of phosphorescence of [Ru (bpy) ₃ ] ²⁺ complex as a standard material

I _std : phosphorescence intensity of the sample complex

Φ _std : Internal quantum efficiency (0.062) of the standard material [(Ru (bpy) ₃ ] ²⁺ complex)

division Example 1 Comparative Example Internal quantum efficiency (Φ) 0.87 / Pt-atom 0.4 / Pt-atom Maximum emission wavelength (nm) 409 570

As shown in Table 1, the platinum complex containing the 1,10-phenanthroline derivative of the present invention has a shorter wavelength luminescence characteristic and a higher internal quantum efficiency than the conventional platinum complex.

Claims (6)

delete delete A platinum complex represented by the following formula (2).
(2)

(In the formula (2)
R ₁ to R ₅ are hydrogen or C ₁ -C ₂₀ alkyl;
p is an integer from 1 to 4;
and q is an integer of 1 to 2.) The method of claim 3,
Platinum complex selected from the following compounds.

The method of claim 3,
The platinum complex has a maximum phosphorescence emission wavelength of 350 to 600 nm. An organic light-emitting device comprising a platinum complex selected from any one of claims 3 to 5.

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