CN1658723A - White organic electroluminescence device and its preparation method - Google Patents

Abstract

This invention discloses a white organ electric induced light apparatus and its producing method. The apparatus makes the Zn(BTZ)2 as the main light material. Produce the polymers and small molecules into thin membrane with a certain thickness, respectively using the methods of circumvolving smearing and vacuum vaporing plating, to obtain the apparatus with the following structure: ITO/PVK; TPD(x nm)/Zn(BTZ) 2; Rubrene(y nm)/Al(z nm). This invention provides a kind of slab type white OLED apparatus with single lighting layer. The apparatus isn't necessary to respectively produce the lighting layer of the three basic colors or carry out complex light-charactering process to them, so it has the characteristics that its making technics is simple and has good repetition, the chroma of the white light is pure and has little change with the additional driving voltage, and so on. It solves the problems that the large area OLED lighting apparatus lights not so symmetrical, the compression resistance is not so good, and so on. The apparatus can completely meet the requirement of the LCD in light, thin and low power wastage, and is very suitable to be used as the apheliotropic source of this kind of display apparatus.

Description

A kind of white color organic electroluminescence device and preparation method thereof

[technical field]: patent of the present invention relates to a kind of novel flat-plate escope spare---and be white color organic electroluminescence device (OLED) and preparation method thereof.

[background technology]: current, the research of white color organic electroluminescence device (OLED) is subjected to paying close attention to widely.On the one hand, it can be used as the backlight of the very high LCD of present commercialized degree (LCD), can all satisfy the requirement of LCD in light, thin, low-power consumption, and shown literal, monochromatic light backlight that the figure geometric ratio is general have higher contrast.On the other hand, contain three kinds of primary color components of red, green, blue in the white light, combine with comparatively ripe microelectronics etching color filter membrane technology as the single layer structure device that will emit white light, then be expected to access with the White OLED device (as: devices of three kinds of luminescent layer eclipsed forms of red, green, blue of employing such as J.Kido) of other type and compare, preparation technology is simpler (to need not to prepare respectively the luminescent layer of three kinds of primary colours, and they are carried out loaded down with trivial details photoetching process etc. respectively), repeatability is better, the full color OLED device that cost is lower.

Mostly the method for at present traditional in the world acquisition white light is to realize by sandwich construction, promptly adopt the method that three kinds of luminescent layers of red, green, blue are piled up, obtain white light by mixing three primary colors, the weak point of this kind method shows as complicated process of preparation, difficult the grasp, cost is higher, and the white light colourity of device easily changes along with the variation that adds driving voltage, because sandwich construction easily causes self-absorption, general quantum efficiency is all lower in addition.

For the deficiency that overcomes above-mentioned sandwich construction white light parts and large tracts of land white light parts exist luminous not too even, defective such as resistance to pressure is relatively poor.Patent of the present invention provides a kind of single luminescent layer, than large tracts of land and luminous uniform plate White OLED device, this white light parts need not to prepare respectively the luminescent layer of three kinds of primary colours, and they are carried out loaded down with trivial details photoetching process etc. respectively, have simple, the good reproducibility of preparation technology, white light colourity is pure and change very little characteristics with adding driving voltage.

[summary of the invention]: the present invention seeks to solve existing sandwich construction white light parts complicated process of preparation, difficult the grasp, the cost height, and the problem that broad area device is luminous not too evenly, resistance to pressure is relatively poor and colourity easily changes along with the variation that adds driving voltage, a kind of preparation method and device of white color organic electroluminescence device are provided.

Luminescent device provided by the invention comprises successively:

The ito anode conductive glass layer; Hole transmission layer (HTL) PVK (polyvinylcarbazole): TPD (aromatic diamine derivative); Luminescent layer (EML) Zn (BTZ) ₂: Rubrene (5,6,11,12-tetraphenyl four benzos); With metal A L-cathode layer.

The present invention is with 2-(2 '-hydroxy phenyl) benzothiazole chelated zinc (Zn (BTZ) ₂) be the main body luminescent material, utilize rotation to apply and vacuum vapour deposition respectively on electro-conductive glass ITO (about 60 Ω of face resistance) surface, polymer and micromolecule are made certain thickness film successively, obtain having the device of following structure: ITO/PVK: TPD (xnm)/Zn (BTZ) ₂: Rubrene (y nm)/Al (z nm); Wherein, 20≤x≤40nm; 30≤y≤60nm; 60≤z≤100nm, the doping of hole transmission layer PVK: TPD is than between 1: 1～1: 2; Luminescent layer Zn (BTZ) ₂: the doping of Rubrene is than between 0.05%～1.2%.The respective material molecular formula is as follows:

PVK????????????????????????????????????????????????TPD

Zn(BTZ) ₂??????????????????????????????????????????Rubrene

A kind of preparation method of above-mentioned white color organic electroluminescence device comprises:

(1) after the ito glass that will be etched into 4mm * 50mm bar shaped cleans in cleaning agent repeatedly, soaks and ultrasonic cleaning, dried for standby in IR bake at last through isopropyl alcohol, acetone and chloroformic solution respectively again;

(2) PVK and TPD are pressed mass ratio and mixed in 1: 1～1: 2, and be dissolved in the chloroformic solution of 1～2mg/ml, adopt the spin coating method film forming; Low speed 1000～1500rpm, the about 20s of film formation time, high speed 3000～4000rpm, the about 30s of film formation time is placed on after finishing in the dry still and treats solvent evaporates more than 10 hours;

(3) Rubrene is mixed Zn (BTZ) by 0.05%～1.2% mass ratio ₂In, and compacting is in flakes, adopts the vacuum vapour deposition film forming, its condition is: vacuum degree is greater than 8 * 10 ^-4Pa, evaporation current is about 3～5A, and evaporation time is about 12 minutes;

(4) preparation of AL negative electrode is adopted to divide on tungsten alloy stove silk and is hung the long AL silk of about 1～2cm, and by the bar shaped mask plate, vacuum is steamed and crossed skim bar shaped AL on luminescent layer, and vacuum degree is greater than 8 * 10 ^-4Pa, evaporation current is about 30A, and evaporation time is about 12 minutes;

(5) with bar shaped ito anodes all in the above-mentioned device of making one termination dc power anode, all bar shaped AL negative electrode one termination dc power cathodes obtain dot matrix larger area OLED device.

Advantage of the present invention and good effect: 1, the invention provides the plate White OLED device of a kind of single luminescent layer, this white light parts need not to prepare respectively the luminescent layer of three kinds of primary colours, and they are carried out loaded down with trivial details photoetching process etc. respectively, have simple, the good reproducibility of preparation technology, white light colourity is pure and change very little characteristics with adding driving voltage;

2, the present invention has solved problems such as the large-area OLEDs luminescent device is luminous not too evenly, resistance to pressure is relatively poor with dot matrix way, is prepared into multiple spot (3 * 3mm ²) simultaneously luminous than large tracts of land (5 * 6cm ²) luminescent device;

3, this single luminescent layer provided by the invention, dot matrix are than large-area flat-plate type White OLED device, in light, thin, low-power consumption, can satisfy the requirement of LCD fully, be very suitable for backlight as this class display spare, it also has littler power consumption than general monochromatic light backlight, higher contrast and brightness simultaneously.And it is combined with comparatively ripe microelectronics etching color filter membrane technology, then be expected to access panchromatic demonstration.

[description of drawings]:

Fig. 1 is a white electroluminescence device concrete structure schematic diagram;

Fig. 2 is luminescent layer different levels of doping device electroluminescent spectrum and corresponding chromaticity coordinates value;

Fig. 3 be luminescent layer optimum doping than the time EL spectrogram of device during in different direct voltage drive.

[embodiment]:

Embodiment 1:

At first ito glass is etched into the strip of 4mm * 50mm, again PVK (polyvinylcarbazole) and TPD (aromatic diamine derivative) are mixed by 1: 1～1: 2 (mass ratio) and (as got 1: 1, or 1: 1.5, or all can at 1: 2, this example was got 1: 1), and be dissolved in chloroformic solution with 1～2mg/ml, utilize spin coating method that hole transmission layer PVK: TPD is prepared into the film that thickness is 20～40nm, concrete membrance casting condition is: low speed 1500rpm, the about 20s of film formation time, high speed 3800rpm, the about 30s of film formation time; Utilize vacuum vapour deposition with luminescent layer Zn (BTZ) then ₂: Rubrene (5,6,11,12-tetraphenyl four benzos) mixes than being prepared into the film that thickness is 30～60nm by difference, and evaporation conditions is: vacuum degree is greater than 8 * 10 ^-4Pa, evaporation current is about 3～5A, and evaporation time is about 12 minutes.By the bar shaped mask plate, the vacuum steaming is crossed skim bar shaped AL and is done negative electrode on luminescent layer at last, and its thickness is 60～100nm, has single luminescent layer than the large tracts of land organic electroluminescence device thereby make, and concrete structure as shown in Figure 1.

Wherein Rubrene mixes Zn (BTZ) by the different quality degree ₂Among, be respectively 1.2%, 0.12%, 0.08%, and 0.05%.

Embodiment 2:

After the device preparation is finished, with all bar shaped ITO one termination dc power anodes, all bar shaped AL negative electrode one termination dc power cathodes, increase driving voltage gradually, in 8.5～22.5V interval, device with optimum doping ratio can obtain to stablize than the large tracts of land white electroluminescence, and its maximum brightness reaches 4048cd/m ², corresponding luminous efficiency is 4.05cd/A.

Accompanying drawing 2 is under the 20V direct voltage drive, Zn (BTZ) ₂In the doping percentage composition of Rubrene be respectively 1.2%, 0.12%, 0.08% and 0.05% o'clock, the electroluminescence of each device (EL) spectrogram and corresponding C IE (1931) chromaticity coordinates value thereof.

Accompanying drawing 3 is Zn (BTZ) ₂: the doping ratio of Rubrene is 0.05% o'clock, the EL spectrogram of device under different direct voltage drive.

Device all can be stablized acquisition than the uniform white electroluminescence of large tracts of land during different driving voltage, when between ito anode and AL negative electrode, adding driving DC voltage and being 8.5～22.5V, and corresponding chromaticity coordinates value such as following table:

The table optimum doping is than CIE (1931) the chromaticity coordinates value of device under the different driving voltage

Driving voltage	???8.5V	????10V	???15V	???20V	???22.5V
						The CIE chromaticity coordinates	??X＝0.349 ??Y＝0.372	??X＝0.329 ??Y＝0.351	??X＝0.335 ??Y＝0.344	??X＝0.341 ??Y＝0.334	??X＝0.347 ??Y＝0.328

Claims (5)

1, a kind of white color organic electroluminescence device is characterized in that this luminescent device comprises successively:

1) ito anode conductive glass layer;

2) hole transmission layer PVK: TPD;

3) luminescent layer Zn (BTZ) ₂: Rubrene;

4) AL cathode layer.

2, white color organic electroluminescence device according to claim 1, the mass ratio that it is characterized in that hole transmission layer PVK: TPD are between 1: 1～1: 2, and thickness of hole transport layer x is 20≤x≤40nm.

3, white color organic electroluminescence device according to claim 1 and 2 is characterized in that luminescent layer Zn (BTZ) ₂: the mass ratio of Rubrene is between 0.05%～1.2%, and light emitting layer thickness y is 30≤y≤60nm.

4, white color organic electroluminescence device according to claim 1 and 2 is characterized in that AL cathode layer thickness z is 60≤z≤100nm.

5, the preparation method of the described white color organic electroluminescence device of a kind of claim 1 is characterized in that this method may further comprise the steps:

(1) after the ito glass that will be etched into 4mm * 50mm bar shaped cleans in cleaning agent repeatedly, soaks and ultrasonic cleaning, dried for standby in IR bake at last through isopropyl alcohol, acetone and chloroformic solution respectively again;

(2) PVK and TPD are pressed mass ratio and mixed in 1: 1～1: 2, and be dissolved in the chloroformic solution of 1～2mg/ml, adopt the spin coating method film forming; Low speed 1000～1500rpm, the about 20s of film formation time, high speed 3000～4000rpm, the about 30s of film formation time is placed on after finishing in the dry still and treats solvent evaporates more than 10 hours;

(3) Rubrene is mixed Zn (BTZ) by 0.05%～1.2% mass ratio ₂In, and compacting is in flakes, adopts the vacuum vapour deposition film forming, its condition is: vacuum degree is greater than 8 * 10 ^-4Pa, evaporation current is about 3～5A, and evaporation time is about 12 minutes;

(4) preparation of AL negative electrode is adopted to divide on tungsten alloy stove silk and is hung the long AL silk of about 1～2cm, and by the bar shaped mask plate, vacuum is steamed and crossed skim bar shaped AL on luminescent layer, and vacuum degree is greater than 8 * 10 ^-4Pa, evaporation current is about 30A, and evaporation time is about 12 minutes;

(5) with bar shaped ito anodes all in the above-mentioned device of making one termination dc power anode, all bar shaped AL negative electrode one termination dc power cathodes obtain dot matrix larger area OLED device.

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