JP4209747B2 - Spectral measurement method using slab type optical waveguide - Google Patents

Description

The present invention, for example an organic electronic element forming material is preferably used in the organic electroluminescence element or the like is related to the spectrum measuring method for measuring by using the optical waveguide of the slab, further, utilizes optical waveguide slab using spectral method for measuring by a temporal spectral data of the coating film interface resulting from the measurement process, the new information obtained from the temporal analysis data of the coating film obtained from other analytical means The present invention relates to a spectrum measurement method that can be used to select an optimal composition based on the above.

  Unlike a liquid crystal display, an organic electroluminescence display using an organic substance as a light emitter is a self-luminous display that uses fluorescence or phosphorescence emitted from an excited light emitter. For this reason, it is attracting attention as a next-generation display because it has a simple film structure and can be expected to have high-speed response that can support moving images.

  As an organic electroluminescence element (hereinafter referred to as organic EL element) constituting an organic electroluminescence display (hereinafter referred to as organic EL display), an organic EL element having an organic compound thin film formed by vacuum deposition or the like as a light emitting film Has been actively researched and partly put into practical use. However, organic compounds that can be deposited by vacuum deposition are low molecular compounds, and in organic EL devices using such low molecular compounds, crystallization and aggregation of organic films occur over time, resulting in deterioration of the device and device lifetime. There are problems such as lowering, and further research and development is continuing.

  On the other hand, an organic EL element using a high molecular material or a coating type low molecular material as a light emitting material has been proposed. Since these organic compounds can be dissolved or dispersed in a solvent to form a coating solution for forming an organic EL device, there is an advantage that a large area organic EL device can be produced very efficiently with the coating solution. . Therefore, in recent years, active research has been conducted on the development of coating-type organic electronic element forming materials that can achieve high luminous efficiency and long life, and on the study of solvents and additive substances to be blended with the organic electronic element forming materials. Yes.

  However, in the case where an organic EL element is formed using the coating solution for forming the organic EL element described above, the composition of the organic compound material, the solvent, the additive substance, and the like in the coating solution determines how the light emitting film is formed. It has not always been clarified as to whether it is involved in the light emission efficiency and lifetime of the formed light emitting film. One reason for this is that the characteristics of organic EL elements, such as luminous efficiency and lifetime, are affected by the mobility and stability of bulk carriers (electrons and holes) in the luminescent film, and the film interface (for example, light emission). It is considered that it is affected by the mobility and stability of carriers at the film-electrode interface, light-emitting film-charge transport film interface, etc., but the analysis at the film interface is more difficult than the bulk analysis. One of the factors is that this is not done sufficiently. In particular, since the organic EL device forming material contains various components such as a solvent, the composition of the coating material can be changed by changing the phenomenon of the film interface during the drying process of the coating film and the phenomenon of the film interface during the deterioration process of the formed light emitting film. It was difficult to analyze in relation to

  As a method for analyzing the above-described interface phenomenon at the film interface, multiple internal reflection infrared spectroscopy, Kelvin probe contact potential difference measurement method, and the like have been proposed. However, since these methods can only measure a specific interface, they are not versatile and have a problem of poor reproducibility, and thus cannot be said to be an effective analysis method for the above-described film interface.

By the way, an apparatus for measuring a light absorption spectrum of an interface, a surface adsorbed material, a thin film, a very small amount of sample, etc. with high sensitivity using a slab type optical waveguide is known (for example, see Patent Documents 1 and 2). reference). This light absorption spectrum measuring device collects light having a certain wavelength width, for example, white light with a lens, and enters the light from a prism set at a predetermined interval from the lens into the optical waveguide film of the slab optical waveguide, The light totally reflected in the optical waveguide film is extracted through a prism with a lens set at a predetermined distance from the prism, and the emitted light is dispersed with a spectroscope and sent to a detector, resulting in an extremely large number of reflections and high sensitivity. It is possible to measure the light absorption spectrum.
JP-A-8-75639 JP 2001-108611 A

The present invention provides a spectrum measurement method for measuring a material for forming an organic electronic element for forming an organic electronic element having excellent reliability using a slab type optical waveguide, and uses the spectrum measurement method , Organic electronic elements for forming highly reliable organic electronic elements based on information obtained from spectral data obtained from the measurement method and analytical data obtained from other analytical means An object of the present invention is to provide a spectrum measurement method that can also be used for selecting the composition of the forming material.

The spectral measurement method using the slab type optical waveguide according to the present invention for solving the above-described problems includes an incident light side prism into which intermittent light is introduced, and an optical waveguide into which the intermittent light introduced into the incident light side prism is incident. An outgoing light-side prism that is introduced after being emitted from the optical waveguide layer after repeated total reflection in the optical waveguide layer, and the intermittent light incident on the optical waveguide layer; An ultraviolet-visible absorption spectrum measuring method using a slab type optical waveguide having an outgoing light side lens for extracting the introduced intermittent light and an outgoing light side optical fiber for sending the intermittent light extracted by the outgoing light side lens to a spectrometer In addition, a measurement sample made of an organic electronic element forming material is placed on the optical waveguide layer between the incident light side prism and the output light side prism, and is adjacent to the measurement sample. And performing spectral measurements the portion without the sample provided in a band shape on.
In the spectrum measurement method using the slab type optical waveguide of the present invention, the spectrum measurement is preferably performed while applying an external element that causes a change over time, and the external element is temporarily or intermittently. It is preferable that the element is one or more elements selected from heat, light, current, and magnetism that are applied continuously or continuously, and the organic electronic element forming material is an organic electroluminescent element forming material. preferable.

In the spectrum measuring method using the slab type optical waveguide of the present invention, a process of preparing a plurality of organic electronic element forming materials having different compositions, and each of the plurality of organic electronic element forming materials over time A process of measuring a change in the state of the interface between the organic electronic element forming material and the optical waveguide as a spectrum while applying or applying an external element that causes a change, and a plurality of organic electronic element forming materials For each, the spectrum is expanded over time, and a change in the organic electronic element forming material is measured for each step by one or two or more different kinds of analysis means, and the plurality of organic electronic element forming materials for each, the process of comparing the data of the spectrum, and a heterogeneous analysis data measured by said heterologous analyzing means, said By comparison with the spectrum of the data obtained from each OED forming material having said heterologous analysis data, and the process of selecting the optimum composition of an organic electronic device forming material, be configured to have a Good.
In the present invention, an external element is given to an organic electronic device material that is a measurement sample to perform spectrum measurement while changing the coating film over time, and one or two or more in a changed state based on the measurement result over time. Perform heterogeneous analytical measurements. Then, the results of both are compared. And by making such a comparison between organic electronic element forming materials having different compositions, it is possible to compare the influence of the composition on the interface state change, so that the comparison result shows the optimal composition of the organic electronic element forming material. Can be selected. Therefore, according to the present invention, for each of the plurality of organic electronic element forming materials, the state analysis data of the coating film interface when the coating film state is changed over time by adding an external element, From the analysis data of the coating film bulk in the scene, it is possible to capture state change information for each of the plurality of organic electronic element forming materials. As a result, the state change behavior over time obtained from materials with different compositions can be clarified, and the change in characteristics over time of organic electronic devices made from materials with changed compositions can be predicted. Knowledge for developing materials for organic electronic devices can be obtained and used to develop more desirable organic electronic devices.

In the spectrum measuring method using the slab type optical waveguide of the present invention, (1) a change occurring in the organic electronic element forming material is a coating film forming process of the organic electronic element forming material or an organic electronic element forming Preferably, it is a deterioration process of the organic electronic device formed from the material, its aging process, its aging process, or its light irradiation process, and (2) the heterogeneous analysis means includes a thermal analysis means, a mass analysis means, and Preferably, it is one or more means selected from spectroscopic analysis means. (3) Two measurement results at the same interface of the organic electronic element forming material or an organic electronic element obtained from the organic electronic element forming material. Dimensional information and time-dependent information of the measurement result are combined into three-dimensional data, and the organic electronic element forming material or the optical The information processing process of analyzing a change in the state of the interface with the road, further comprising, it is preferable.

As described above, according to the spectrum measuring means using the slab type optical waveguide of the present invention, it is possible to clarify the state change behavior with time obtained from materials having different compositions, and to produce the materials by changing the composition. Therefore, it is possible to predict changes in the characteristics of the organic electronic device over time, so that knowledge for developing an optimal material for an organic electronic device can be obtained and used for the development of a more desirable organic electronic device.

Conventionally , it was not possible to select an optimal composition for forming an organic electronic device unless the device was manufactured and the characteristics were evaluated. However, according to the composition selection method of the present invention, spectral data for a plurality of materials having different compositions. And analytical data measured by different types of analysis means can be compared and the chemical state can be analyzed, so the direction of selection work can be clarified without the need for conventional device fabrication and characteristic evaluation. The selection can be greatly simplified. In addition, it is possible to investigate some correlation between changes in the electronic state and orientation state of the material by the interface UV-visible absorption spectrum and the chemical structure and mass change of the material. We can expect utilization for examination.

Hereinafter, the spectrum measuring means using the slab type optical waveguide of the present invention will be specifically described.

(Spectrum measurement using slab type optical waveguide)
First, a spectrum measuring apparatus using a slab type optical waveguide will be described. Slab-type optical waveguide spectroscopy is not infrared spectroscopy that captures vibrations of molecules and functional groups, but is a method that can measure interfacial absorption characteristics in the short wavelength region related to the electronic state and energy band gap over time. Therefore, it is effective for analyzing subtle changes and differences in the film state and dynamics without any chemical bond or chemical structure changes.

  FIG. 1 is a principle diagram of slab type optical waveguide spectroscopy. In the slab type optical waveguide, when light 2 enters the optical waveguide substrate 1, the light 2 is totally reflected on the surface of the optical waveguide substrate 1 and proceeds. At this time, when the coating film 3 to be used for measurement is formed on the optical waveguide substrate, the surface wave of the light 2 that travels by being totally reflected inside the substrate soaks into the coating film slightly. This surface wave is called an evanescent wave 4 and penetrates into the coating film while being attenuated exponentially as described in FIG. The penetration depth (dp) at this time is expressed by the following equation. In the following equation, λ is the incident wave wavelength, θ is the incident angle, n1 is the refractive index of the waveguide substrate, and n2 is the refractive index of the environment around the coating film or the sample film.

  In this slab type optical waveguide, the penetration depth (dp) is very shallow, and information on only molecules existing within 1 μm from the surface of the optical waveguide substrate 1 is selectively and nondestructively analyzed by adjustment. Can do. Further, by using the thinner optical waveguide substrate 1, the number of reflections can be increased, and measurement can be performed with higher sensitivity. Examples of the spectrum measuring apparatus using the slab type optical waveguide include measuring apparatuses disclosed in Japanese Patent Laid-Open Nos. 8-75639 and 2001-108611, and more specifically, system instruments. The SIS-50 type | mold apparatus by a company can be mentioned.

  FIG. 2 is a block diagram showing an example of a spectrum measuring apparatus using a slab type optical waveguide disclosed in Japanese Patent Application Laid-Open No. 8-75639. In FIG. 2, as the light source 10, a light source that emits light having an arbitrary wavelength range from far ultraviolet to far infrared is used, for example, an Xe lamp is used. The light chopper 30 turns the light from the light source 10 into intermittent light having a constant period, and is provided between the light source 10 and the incident light side optical fiber 31. The sample measuring unit includes an incident light side lens 11, an outgoing light side lens 15, an incident light side prism 12, an outgoing light side prism 14, a slab type optical waveguide 13, and a position control mechanism 16. The incident light side lens 11 is provided at the distal end on the exit side of the incident light side optical fiber 31, and the outgoing light side lens 15 is provided at the distal end on the entrance side of the outgoing light side optical fiber 32. Note that, as described in JP 2001-108611 A, an optical coupling method that does not use a prism can be applied.

  FIGS. 3 and 4 are a plan view and a cross-sectional view of the slab type optical waveguide. The incident light side prism 12 and the outgoing light side prism 14 are arranged on the slab type optical waveguide 13. Each of the prisms 12 and 14 is elongated so that the sample 54 and the reference portion 53 can be measured without re-installing the prism. The slab optical waveguide 13 includes a substrate 51 for supporting the optical waveguide layer 52 and an optical waveguide layer 52. A sample 54 is placed in a strip shape on one side of the slab optical waveguide 13, and the opposite side, that is, the portion without the sample 54 becomes a reference portion 53.

  As shown in FIG. 2, the detection unit includes a spectrometer 41, a photomultiplier tube 43, an amplifier 44, and a computer 42. The white light emitted from the light source 10 is converted into intermittent light having a constant period by the light chopper 30 and then introduced into the incident light side optical fiber 31. The intermittent light introduced into the incident light side optical fiber 31 passes through the incident light side optical fiber 31 and is collected by the incident light side lens 11 provided at the tip of the light output side, and is introduced into the incident light side prism 12 at an appropriate angle. Is done. The intermittent light collected by the incident light side lens 11 is introduced into the incident light side prism 12, then enters the optical waveguide layer 52 of the slab type optical waveguide 13, and is intermittently incident on the optical waveguide layer 52. The light repeats total reflection in the optical waveguide layer 52, then exits from the optical waveguide layer 52, and is introduced into the outgoing light side prism 14. The intermittent light introduced into the outgoing light side prism 14 is extracted by the outgoing light side lens 15 provided at the light incident side tip of the outgoing light side optical fiber 32 and sent to the spectroscope 41 by the outgoing light side optical fiber 32. . The intermittent light split by the spectroscope 41 is sent to the computer 42 via the photomultiplier tube 43 and the amplifier 44, and is subjected to arithmetic processing to obtain a spectrum.

  FIG. 5 shows a spectrum measuring apparatus using a slab type optical waveguide preferably applied to the present invention. The spectrum measuring apparatus using the slab type optical waveguide shown in FIG. 5 is an apparatus capable of simultaneously performing multiple reflection type ultraviolet visible absorption spectrum measurement and fluorescence emission spectrum measurement. This measuring apparatus includes an ultraviolet-visible absorption CCD spectrometer 7 that detects a multiple reflection type ultraviolet-visible absorption spectrum between the coating film 3 and the optical waveguide substrate 1. Moreover, the fluorescence PMT spectrometer 8 which detects the fluorescence emission 9 taken out from the optical waveguide is provided. Reference numeral 5 is a prism, and reference numeral 6 is a reflection mirror.

  This multiple reflection type UV-visible absorption spectrum measurement reveals the correlation between the electronic state change at the interface and the chemical bond change, and obtains UV-visible absorption spectrum data, which is information derived from the functional group and chemical structure of the coating film 3. In the fluorescence emission spectrum measurement, the relationship between the change in the electronic state of the interface and the emission spectrum characteristic is clarified. In particular, the fluorescence emission spectrum data which is important emission characteristic information in the organic EL element characteristic is obtained. It is effective for.

  This spectrum measuring apparatus outputs spectral information with time obtained from the above spectroscopes 7 and 8 to the analyzing apparatus 101. The analysis apparatus 101 shown in FIG. 5 is not particularly limited as long as it has a function of processing the obtained spectral information so as to be analyzable, and is an information processing apparatus or an image display apparatus incorporating a calculation function such as a personal computer, or A printer device with a built-in arithmetic element can be given. The analysis apparatus 101 can display analysis information with respect to the time axis, for example, as shown in FIG.

(Composition selection method of organic electronic element forming material)
The composition selection method of the present invention is a composition selection method using the spectrum measuring means using the above-described slab type optical waveguide and one or more heterogeneous analyzing means, and (i) a plurality of different compositions A process for preparing the organic electronic element forming material, and (ii) applying or applying an external element that causes a change over time for each of the plurality of organic electronic element forming materials. A process for measuring a change in the state of the interface between the element forming material and the optical waveguide as a spectrum; and (iii) for each of the plurality of organic electronic element forming materials, the spectrum is expanded over time to A process of measuring the change occurring in the element forming material by the heterogeneous analysis means step by step; and (iv) the spectral data for each of the plurality of organic electronic element forming materials And (v) a process for comparing the heterogeneous analysis data at each stage, and (vi) spectral data obtained from each of the plurality of organic electronic element forming materials and heterogeneous analysis data at each stage. And a process for selecting the optimum composition of the organic electronic element forming material. Hereinafter, the processes (i) to (vi) will be described.

(Preparation process)
The organic electronic device material that is the target of the composition selection method of the present invention is, for example, an organic EL device forming material, as a hole transport layer material, an aqueous material having polythiophene or a derivative thereof, polyvinylcarbazole or a derivative thereof. An example is a non-aqueous material having Moreover, as a material for light emitting layers, the non-aqueous material which has polyfluorene, polyphenylene vinylene, or those derivatives can be mentioned as an example. It should be noted that it is not preferable to form the light emitting layer with water-based materials and the nature of organic EL that is vulnerable to moisture.

  Examples of the water-based hole transport layer material ink usually include an aqueous solution or an aqueous dispersion containing 1 to 5% by weight of polythiophene or a derivative thereof.

  Moreover, as a non-aqueous type material ink for positive hole transport layers, the organic solvent solution which contains 1 to 5 weight% of polyvinyl carbazole or its derivative normally is mentioned.

  Moreover, as a non-aqueous light emitting layer ink, an organic solvent solution containing 1 to 5% by weight of polyfluorene or a derivative thereof is usually mentioned. In addition, as an organic solvent, the aromatic organic solvent represented by toluene and the halogen type organic solvent represented by dichloroethane can be used.

  The composition selection method of the present invention is a method that is preferably applied to the selection of the types of constituent components of the organic electronic device forming material and the selection of the content of the selected constituent components. Therefore, in the application of the composition selection method of the present invention, first, a plurality of materials for forming an organic electronic element having different compositions (particularly, a material for a light emitting layer that greatly affects EL light emission characteristics in an organic EL element) is prepared.

  Examples of the prepared organic electronic element forming material include a p-xylene solution (organic EL element forming material A, hereinafter referred to as A material) having a polyfluorene derivative of 1% by weight, and an o-xylene solution (organic EL). The element forming material B. Hereinafter, it will be described as an example.

(Measurement process I)
Next, for each of the prepared A material and B material, an external element that causes a change with time is applied or applied, and the state of the interface between the coating film 3 made of each material and the optical waveguide substrate 1 is applied. The change is measured as a spectrum.

  By applying an external element to the coating film 3 over time, for example, a spectrum over time in the coating film forming process such as a drying process of the coating film 3 can be measured, and a deterioration process of the organic EL element, It is possible to measure a spectrum over time in the aging process, the aging process, or the light irradiation process.

  Here, the coating film forming process refers to, for example, after applying the A or B material for forming an organic EL element on the optical waveguide substrate, the solvent contained in each material is removed, or the compound reacts. In other words, it is a process of changing with time formed in the film. In addition, the deterioration process is, for example, a time-dependent change process in which the function of the formed film gradually decreases. The aging process is a change over time in normal temperature storage without applying an external element of heat or light energy. An aging process is a change with time when an external element of thermal energy is applied. The light irradiation process is a change with time when an external element of light energy is involved.

  A coating film is a film | membrane formed by apply | coating A material or B material for organic EL element formation. Examples of the material for forming the coating film include materials for forming organic EL elements such as the above-described A material and B material, materials for organic semiconductors, materials for solar cells, and the like. More specifically, as described above, the organic EL element forming material is a light emitting material such as a low molecular light emitting material such as coumarin, an organic compound such as a conjugated polymer material such as polyphenylene vinylene, and toluene, xylene or the like. Organic solvents such as aromatic solvents and halogen-containing solvents such as dichloroethane are included. The organic semiconductor forming solution and the organic solar cell forming solution also contain an organic solvent similar to the organic EL element forming material.

  “Applying” an external element means measuring after applying the external element temporarily, and “while applying” an external element means applying the external element intermittently or continuously. While measuring. Therefore, the temporal change of the coating film 3 can be imparted by applying external elements temporarily, intermittently or continuously.

  The external element is one or more elements selected from heat, light, current, and magnetism applied temporarily, intermittently or continuously. By applying these external elements to the coating film, it is possible to measure time-varying information such as the coating film forming process, deterioration process, aging process, aging process, and light irradiation process of the coating film.

  Heat includes warm and cold. Light includes light with different wavelengths, such as laser (monochromatic light with uniform phase), ultraviolet light, visible light, infrared light, etc., and also includes electron beams and radiation, and radiation such as X-rays and γ-rays. Is defined by the concept that is also included. The current may be direct current or alternating current, and the current value can be applied in various values. Magnetism is a case where an arbitrary magnetic field is applied, and may be a magnetic field by a magnet or an electromagnet.

  Examples of the device for applying heat include a hot plate and a heat ray heater. Examples of the device for irradiating light include an ultraviolet exposure device and an electron beam exposure device. For example, a direct current power supply device or an alternating current power supply device can be used, and examples of the device for applying magnetism include an electromagnet and a strong permanent magnet.

  The term “temporarily” refers to an application style that is applied when the chemical information of the coating film changes with time by applying the above-described external element once. In addition, intermittently is an application style applied when the chemical information of the coating film changes with time by applying the above-described external elements at regular intervals. Continuously refers to an application style that is applied when the chemical information of the coating film changes over time by continuously applying the above-described external elements.

  In the present invention, an appropriate external element is selected from various external elements according to the material characteristics of the coating film or according to the relationship between the applied external element and the coating film. At this time, one type of external element may be applied, or two or more types of external elements may be applied. When two or more types of external elements are applied, the application style (temporary, intermittent, continuous) of each external element may be the same or different. For example, one external element can be applied continuously and the other external element can be applied intermittently.

  In the measurement process I of the composition selection method of the present invention, it is possible to obtain time-dependent information on the interface state between the coating film and the optical waveguide. The information thus obtained is effectively used in the analysis of the electronic state of the film interface in the drying process, deterioration process, thermal aging process, aging process or light irradiation process.

(Measurement process II)
Next, with respect to each of the prepared A material and B material, the spectrum obtained using the slab type optical waveguide is developed on the time axis, and changes occurring in each of the A material and the B material are shown for each stage. Measure with a heterogeneous analytical tool.

  As the heterogeneous analysis means, one or more means selected from thermal analysis means, mass analysis means and spectroscopic analysis means are preferably mentioned, but other means may be used, for example, nuclear magnetic resonance analysis (NMR), microscopic observation, etc. Different types of analysis means can be used.

  Examples of the thermal analysis means include thermal weight loss change measurement (TGA), differential thermal analysis measurement (DSC), temperature programmed desorption gas analysis measurement (TDS), and the like. Among these, by interfacing with general thermal analysis means such as thermogravimetric decrease change measurement (TGA) and differential thermal analysis measurement (DSC), information on the interface weight change and energy change can be obtained, The relationship between the change in the electronic state of the interface and the change in the thermal behavior of the film becomes clear. In addition, as a mass spectrometric measurement device, by linking a general mass spectrometric device (MS), it is possible to obtain information on gas components generated during thermal changes and temporal changes at the film interface, and outgassing. Between the analysis results, the relationship between the change in the electronic state of the interface and the decomposition products and outgas components generated from the film during the change process becomes clear. The spectroscopic analyzers include infrared spectroscopic measurement (IR), fluorescence emission spectroscopic measurement, Raman spectroscopic measurement, X-ray photoelectron spectroscopic measurement (XPS), sum frequency spectroscopic measurement (SFG), and second harmonic spectroscopic measurement (SHG). And the like. Of these, information on chemical bonds and chemical structure changes can be obtained by linking infrared spectroscopy (IR), and the relationship between the electronic state of the interface and the chemical structure change and alteration of the film is clear. It becomes.

  As for other heterogeneous analysis means, examples of the nuclear magnetic resonance analyzer include pulse nuclear magnetic resonance analysis and solid state nuclear magnetic resonance analysis. By linking these general nuclear magnetic resonance analyses, the relationship between relaxation time changes and chemical structure changes becomes clear. Further, by linking with microscopic observation with an electron microscope, a fluorescence microscope, or the like, the relationship with the shape and shape change becomes clear.

Time axis expansion is to organize the data captured at regular time intervals and display them in a three-dimensional time series, for example, to display the time series of changes in the spectrum that dry during the heat treatment every few seconds. It is done.

  In addition, measuring the change occurring in each of the A material and the B material with the heterogeneous analysis means for each step means, for example, measuring the thermal analysis measurement such as TGA or the mass spectrometry measurement such as MS in each step, and analyzing the data. It is to be. At this time, stepwise means that in the case where changes occurring in each of the A material and the B material are divided into a plurality of steps, a state for each step is created and the heterogeneous analysis data is maintained in that state. Is to measure. In addition, when the change which arises in each of A material and B material is not divided into several steps, suppose that fixed time is set and it measures at the space | interval.

  In the measurement process II of the composition selection method of the present invention, the spectrum is developed on the time axis, and changes occurring in each of the A material and the B material are measured by the heterogeneous analysis means for each stage. In this case, it is important to perform measurement while maintaining the measurement conditions of the heterogeneous analysis means in the same state as the state of each stage of the coating film, and as a result, the obtained analysis data is, for example, the chemistry of the material. It is effectively used in the analysis of structural changes and material weight changes.

(Comparison process)
Next, for each of the prepared A material and B material, as shown in FIG. 6 to be described later, the spectrum data obtained by using the slab type optical waveguide and the heterogeneous analysis at each stage described above. Compare the data.

The above-mentioned spectrum data and heterogeneous analysis data are compared by displaying each data in multiple steps or at certain time intervals. When a specific change is confirmed in the time base expansion of the spectrum obtained from the slab type optical waveguide, it is confirmed whether or not a specific change corresponding to the heterogeneous analysis measurement at that stage has occurred. As a result of this comparison, when a correlation is obtained between both data changes, it is expected that the electronic state and orientation state change of the material and the chemical structure and mass change of the material are generated with some correlation. In some cases, only specific changes in the spectral data obtained from the slab type optical waveguide or only specific changes in the heterogeneous analysis data are observed, and correlation may not be confirmed. There is concern about adverse effects on product performance.

(Selection process)
Next, the spectrum data obtained from each of the prepared A material and B material is compared with the heterogeneous analysis data at each stage, and the optimum composition of the organic electronic element forming material is selected.

  In this selection process, comparison between materials is performed based on the comparison result between the spectral data for each material obtained in the above comparison process and the heterogeneous analysis. That is, the comparison result of the A material is compared with the comparison result of the B material, and the optimum material is selected based on the result that is clear from the comparison between the two.

  In particular, when selected as a material for an organic electroluminescence element, in the process of thermal aging, aging process or light irradiation process, even in the change of spectral data obtained from the slab type optical waveguide, However, if a specific behavior such as an abrupt change in intensity or a peak shift is confirmed, crystallization, agglomeration, material alteration or decomposition, etc. usually occur, resulting in deterioration of device characteristics. It is determined that the material composition is appropriate. Accordingly, a material composition that does not have a specific change even in a change in spectral data obtained from a slab type optical waveguide and that does not have a specific change in a change in heterogeneous analysis data is selected as an optimum material composition.

  For example, when the time axis is expanded from each measurement of the A material, there is no specific change in the spectral data obtained from the slab type optical waveguide, and there is no specific change in the change in the heterogeneous analysis data. A comparison result is obtained, and if a specific change is confirmed in any of the data changes when the time axis is expanded from each measurement of the B material, the A material is selected as the optimum material composition. The

  In addition, in the case of changes in the spectral data obtained from the slab type optical waveguide and in the heterogeneous analysis data, if there is a peculiar change, there is a concern about the deterioration of device characteristics and the problem of product performance lot fluctuation, As a material for organic electroluminescence elements, it is judged that the material composition should be particularly avoided.

  Efficient and highly accurate by performing the same selection in the time axis development during the processing method (ripening, aging, light irradiation processing, etc.) performed at the time of film formation, and selecting the optimum composition and removing the inappropriate composition. The material composition for the organic electroluminescence element can be selected.

  However, if there is a material application that favors crystallization or certain alteration other than organic electroluminescence elements, the above selection criteria are reversed. That is, the B material in which a peculiar change is confirmed in the change of the spectrum data obtained from the slab type optical waveguide and the change of the heterogeneous analysis data can be an optimum material composition for this different application.

(Information processing process)
In the composition selection method of the present invention, the prepared A material and B material or the two-dimensional information of the measurement result at the same interface of the organic electronic element obtained from each of these materials and the time-lapse information of the measurement result are combined. An information processing process for analyzing the state change of the interface between the A material and the B material and the optical waveguide can be added using the three-dimensional data.

  The two-dimensional information is the surface information (X axis-Y axis) of the coating film or element formed on the plane, and the three-dimensional data is the change in the temporal data of the film or element in the surface over time. It is data of a three-dimensional state change represented by the Z axis as an axis. In the present invention, by analyzing with this three-dimensional data, it is possible to track the change in state over time in the in-plane distribution of the film or element.

  Further, the above-described spectrum data and analysis data, and further their analysis results can be compared with the characteristic data of the organic electronic element formed of the A material and the B material, and the relationship between them can be further analyzed. Examples of the characteristic data of the organic electronic element include energy conversion efficiency data, lifetime, stability data, and the like. For example, in an organic EL element, light emission efficiency data, light emission luminance data, light emission lifetime data, and the like can be given. This characteristic data is input to a computer and compared with spectrum data measured by a spectrum measuring apparatus using a slab type optical waveguide or analysis data measured by a heterogeneous analysis means. As a result of comparison, when the specific result of the characteristic data corresponds to the spectral data and analytical data, and also to the analytical results, the state change of the interface behavior indicated by the spectral data has an effect on the characteristic. Becomes clear.

  FIG. 6 summarizes the composition selection method of the present invention. According to the composition selection method of the present invention, each of a plurality of materials for forming an organic electronic element (A material and B material) is applied when an external element is added and the coating state is changed over time. The state change information of the material can be captured from the state analysis data of the film interface and the analysis data of the coating film bulk in each scene. As a result, it is possible to clarify the time-dependent state change behavior of the A material and the B material, and to predict the time-dependent characteristic change of each organic electronic device made of the A material and the B material. Knowledge for developing electronic devices can be obtained and used to develop more desirable organic electronic devices.

  The composition selection method of the present invention can be applied to materials other than organic electronic element forming materials such as organic EL element forming materials such as the A material and B material described above. For example, liquid phase to solid film, solid film to liquid phase, gas phase to solid film (including vapor deposition), solid film to gas phase (including sublimation), liquid phase to gas phase, gas phase to liquid phase, It is also effective for analysis of state changes including phase transition such as crystal to amorphous and amorphous to crystal. More specifically, a deposition film forming process, an adhesive bonding process, a coating film (coating containing an organic solvent, a lacquer or a lacquer or a lacquer that changes to a solid film), a functional material (plasticizer, It can be effectively used as an analytical process for analyzing in a chemical state a phase change process including a polymer resin shaping process to which an additive is added) and an orientation of liquid crystal to which a potential is applied.

  In the above description, the A and B materials of the organic EL element forming material have been described as examples. However, the present invention is not necessarily limited thereto, and an optimum material is selected by comparing three or more types of materials. Can be selected.

(Apparatus used for composition selection method)
The apparatus 51 used for the composition selection method of the material for forming an organic electronic element of the present invention includes, for example, a spectrum measuring means 52 using a slab type optical waveguide as shown in FIG. 56 is a device that realizes the above-described composition selection method of the present invention. The device 51 is provided with means (not shown) for applying an external element that causes a change over time. Means 53, 54, and 55 are provided for comparing the spectrum data with the analysis data for each stage or the analysis data over time. As the means, a computer 53 for data analysis is used, and as a device for displaying or outputting the analysis data, a display device 54 or a printer device 55 is used.

  In the apparatus of these embodiments, (i) the spectrum measuring means is preferably a spectroscope for ultraviolet-visible absorption spectrum measurement, and (ii) the heterogeneous analyzing means is a thermal analyzer, a mass spectrometer, and a spectrometer It is preferable that the device is one or two or more devices selected from: (iii) the external element application means is a heating device, a light irradiation device, a current power source, and a magnetic device that can be applied temporarily, intermittently or continuously. It is preferable that it is 1 or 2 or more apparatuses chosen from these. These details are as described above.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1
Preparation process:
As an organic EL element forming material, a solution in which the same EL light emitting material was dissolved in different organic solvents was prepared. Specifically, a polymer green light emitting material manufactured by ADS is used as the EL light emitting material, and the organic solvent is o-xylene, m-xylene, p-xylene, ethylbenzene, general-purpose xylene (o- Xylene: 25%, m-xylene: 43%, p-xylene: 18%, ethylbenzene: 14%) were used to prepare five types of organic EL element forming materials. The polymer green light emitting material was prepared so as to be 1% by weight in each solvent.

Measurement process I:
Using an interfacial ultraviolet-visible spectrometer (SIS-50, manufactured by System Instruments, Inc.) using slab optical waveguide spectroscopy, the drying process of the coating film formed by spin coating with the organic EL element forming material described above Interfacial UV-visible absorption spectrum data was measured over time. The measurement is performed by dropping 0.1 mL of the above-mentioned solutions having different solvent types onto an optical waveguide substrate made of synthetic quartz (manufactured by System Instruments Co., Ltd.), and then gradually drying at room temperature to change the solvent types in the coating film. After volatilization, spectral data over time during the drying process were measured. At this time, the penetration depth of the evanescent wave was about 1 μm and was measured at intervals of about 2 seconds. FIG. 9 is an interface ultraviolet-visible absorption spectrum of the coating film in the drying process for m-xylene (A) and o-xylene (B). In FIG. 9, reference numerals 1 to 4 indicate the measurement order over time. As can be seen from the results in FIG. 9, m-xylene (A) and o-xylene (B) have different interface ultraviolet-visible absorption spectra in the drying process. In addition, what used the solution which used p-xylene and general purpose xylene as a solvent seed was the same result as o-xylene (B). A clear specific behavior (absorption intensity change, maximum peak change) was confirmed from the time axis development of (A), but such a large change was not confirmed from the time axis development of (B).

Measurement process II:
Next, as a heterogeneous analysis means, thermogravimetric loss (TGA) at a stage where a specific behavior was confirmed in the system (A) was measured. As a result of developing the weight reduction profile of the drying process over time, the degree of weight reduction accompanying the volatilization of the solvent is almost constant in the system (B), and the aromatic solvent is gradually evaporating. However, in the system (A), a specific change was confirmed in the weight loss profile. There was a point where the weight loss (solvent volatility) increased at a certain stage.

As a result of outgas analysis by mass spectrometry, it was confirmed that the reduced weight portion (outgas) was the organic solvent used.

Comparison process:
In the system (A), it can be seen that in the measurement process I, the volatilization of the solvent is remarkable in the vicinity of the time when the specific change is confirmed. Here, the crystallization of the material and the orientation change are formed. It is thought that. It is considered that the change in the electronic state and orientation state of the material and the chemical structure and mass change of the material caused a specific change with some correlation. On the other hand, such a decrease was not confirmed in (B).

Selection process:
In an organic electroluminescence element, crystallization of a light emitting material is a fatal problem that deteriorates the performance of the material. Therefore, as a result of comparison, the composition (B), which forms an amorphous film, was selected as the optimum material composition.

(Example 2)
Materials similar to the preparation process of Example 1 were prepared, and the interface UV visible using slab type optical waveguide spectroscopy was used in the aging process process by the hot air of the dryer instead of drying at room temperature as in the measurement processes I and II of Example 1. Spectral measurement and thermogravimetric loss measurement, which is a different kind of analysis means, were performed, and time axis development was performed during the aging process. As a result, the system (A) showed a specific change in the interface UV-visible spectroscopic spectrum change using the optical waveguide spectroscopy and the thermogravimetric decrease behavior, and showed no specific change (B ) And a clear difference. Therefore, even when an organic electroluminescence element forming method that involves an aging process is employed, (B) is still selected as the optimum composition.

(Example 3)
Next, an organic EL element was actually created using materials (A) and (B), and emission characteristic data was measured. The characteristic data of the organic EL element film is the layer configuration of glass substrate / ITO (anode) / PEDOT / PPS (hole transport layer) / organic EL element film (electron transport layer / light emitting layer) / Ca layer / Ag (cathode). The organic EL device was analyzed and examined by measuring the voltage-luminance characteristics (see Table 1), voltage-luminescence efficiency characteristics (see Table 1), and luminescence lifetime characteristics (see Table 1). As is clear from the results in Table 1, m-xylene has a significantly shorter lifetime with a luminance one order of magnitude lower than that of other solvent types and an efficiency of 1/3.

  The specific change of the spectral change obtained from the optical waveguide spectroscopy measurement confirmed in Example 1 and the specific change obtained from the thermogravimetric reduction measurement are considered as follows. First, it can be inferred from the results of the thermogravimetric decrease measurement that the π-electron layer composed of the solvent species in the drying process escapes from the coating film all at once. That is, in the initial stage of the drying process, the laminated structure of π electron plane (polymer organic compound) parallel to the optical waveguide substrate surface / parallel π electron layer (solvent) / parallel π electron plane (polymer organic compound) It is thought that it was temporarily formed, and then, as the drying progresses, the solvent volatilizes all at once, and the parallel π-electron layer (solvent) is lost, which is dramatic as shown in FIG. 9 (A). It is thought that a change in absorption intensity occurs. As a result, it is considered that a laminated structure composed of a π electron plane (polymer organic compound) parallel to the optical waveguide substrate surface / parallel π electron plane (polymer organic compound) is stabilized as it is. This can be explained by the fact that the absorption intensity does not change during the subsequent drying process.

  Such a result of the interface ultraviolet visible absorption spectrum can well explain the characteristic data of the organic EL element film. That is, in the coating type organic EL element film, crystallinity and regularity are not required, and nonuniformity and amorphousness are required. Therefore, a rule formed from a solution using m-xylene as a solvent species is required. The results shown in Table 1 that the film having a typical laminated structure is inferior in characteristics such as luminance, light emission efficiency, and lifetime can be explained without contradiction.

  Conventionally, an optimum organic EL element forming material could not be selected unless the element was manufactured and the characteristics were evaluated. However, according to the selection method of the present invention, the interface ultraviolet-visible absorption spectrum and the characteristic data were compared and applied. By analyzing the chemical state of the membrane interface, it is possible to grasp the phenomenon that the interface UV-visible absorption spectrum change during the drying process means. As a result, by using this analysis result, the direction of the selection work can be clarified without selecting the other organic EL element forming materials and preparing the elements and performing the characteristic evaluation. Significant simplification can be expected.

It is a principle figure of a slab type | mold optical waveguide spectroscopy. It is a block diagram which shows an example of the spectrum measuring apparatus using the slab type | mold optical waveguide currently disclosed by Unexamined-Japanese-Patent No. 8-75639. It is a top view of a slab type | mold optical waveguide. It is sectional drawing of a slab type | mold optical waveguide. This is a spectrum measuring apparatus using a slab type optical waveguide preferably applied to the present invention. It is explanatory drawing about the analysis method of this invention. It is a block diagram which shows an example of the analyzer of this invention. It is an ultraviolet visible absorption spectrum of the organic EL element film | membrane after drying about m-xylene and o-xylene. It is an interface ultraviolet visible absorption spectrum of the coating film in the drying process about m-xylene (A) and o-xylene (B).

Explanation of symbols

1 optical waveguide substrate 2 light 3 film (coating film)
4 Evanescent Wave 5 Prism 6 Reflecting Mirror 7 Ultraviolet Visible Absorption CCD Spectrometer 8 Fluorescent Emission PMT Spectrometer 9 Fluorescence Emission 10 Light Source 11 Incident Light Side Lens 12 Incident Light Side Prism 13 Slab Optical Waveguide 14 Emission Light Side Prism 15 Out Emission side lens 16 Slab type optical waveguide position and angle control mechanism 30 Optical chopper 31 Incident light side optical fiber 32 Optical fiber 33, 34 Lens 41 Spectrometer 42 Computer 43 Photomultiplier tube 44 Amplifier

Claims (8)

An incident light side prism into which intermittent light is introduced;
An optical waveguide layer on which the intermittent light introduced into the incident light side prism is incident;
An outgoing light-side prism that is emitted and introduced from within the optical waveguide layer after intermittent light incident on the optical waveguide layer repeats total reflection in the optical waveguide layer;
An outgoing light side lens for extracting intermittent light introduced into the outgoing light side prism;
An ultraviolet-visible absorption spectrum measurement method using a slab type optical waveguide having an outgoing light side optical fiber that sends intermittent light extracted by the outgoing light side lens to a spectrometer,
On the optical waveguide layer between the incident light side prism and the outgoing light side prism, a measurement sample made of an organic electronic element forming material is placed in a strip shape, and a portion without the sample is adjacent to the measurement sample. A spectrum measurement method using a slab type optical waveguide, characterized in that an ultraviolet-visible absorption spectrum measurement is performed in a band shape.   The spectrum measurement method using a slab type optical waveguide according to claim 1, wherein the spectrum measurement is performed while applying an external element that causes a change over time. The slab type optical waveguide according to claim 2 , wherein the external element is one or more elements selected from heat, light, current, and magnetism applied temporarily, intermittently or continuously. Spectrum measurement method.   The spectrum measuring method using the slab type optical waveguide according to any one of claims 1 to 3, wherein the organic electronic element forming material is an organic electroluminescent element forming material. A process for preparing a plurality of organic electronic element forming materials having different compositions;
For each of the plurality of organic electronic element forming materials, an external element that causes a change over time is applied or applied, and the state change of the interface between the organic electronic element forming material and the optical waveguide is spectrumd. As a process to measure as
For each of the plurality of organic electronic element forming materials, a process of expanding the spectrum on a time axis and measuring a change occurring in the organic electronic element forming material by one or more different kinds of analysis means for each step;
A process for comparing the spectrum data with the heterogeneous analysis data measured by the heterogeneous analysis means for each of the plurality of organic electronic element forming materials,
By comparison with the spectrum of the data obtained from each of the plurality of organic electronic devices forming material and the heterogeneous analytical data, having a process of selecting the optimum composition of an organic electronic device forming material according to claim 1 The spectrum measuring method of any one of -4.   The change that occurs in the organic electronic element forming material is a coating film forming process of the organic electronic element forming material, or a deterioration process of the organic electronic element formed from the organic electronic element forming material, an aging treatment process thereof, and an aging process thereof. The spectrum measurement method according to claim 5, wherein the spectrum measurement method is a treatment process or a light irradiation treatment process.   The spectrum measurement method according to claim 5 or 6, wherein the heterogeneous analysis means is one or more means selected from a thermal analysis means, a mass analysis means, and a spectroscopic analysis means. The two-dimensional information of the measurement result at the same interface of the organic electronic element forming material or the organic electronic element forming material obtained from the organic electronic element forming material and the time-dependent information of the measurement result are combined into three-dimensional data, and the third order The spectrum measurement method according to any one of claims 5 to 7, further comprising an information processing process for analyzing a state change of an interface with the organic electronic element forming material or the optical waveguide using original data.

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