TWI555057B - Organic vapor jet printing with a blanket gas - Google Patents

Description

Organic vapor jet printing by filling gas

This invention relates to an organic vapor jet printing (OVJP).

The claimed invention is one or more of the following: and/or one or more of the following parties to reach a joint university company research agreement: Michigan State University Board of Directors, Princeton University Board of Directors, University of Southern California Board of Directors and Universal Display Corporation. The agreement is valid for the production of the claimed invention on the day before and before, and the claimed invention was made for the activities carried out within the scope of the agreement.

Optoelectronic devices using organic materials have become increasingly desirable for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, and therefore, organic optoelectronic devices have the cost advantage over inorganic devices. Additionally, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as manufacturing associated with flexible substrates. Examples of organic optoelectronic devices include organic light-emitting devices (OLEDs), organic optoelectronic crystals, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials have performance advantages over conventional materials. For example, the wavelength at which the organic light-emitting layer emits light can generally be easily tuned by a suitable dopant.

The OLED utilizes a thin organic film that emits light when a voltage is applied to the device. For applications such as flat panel displays, lighting and backlighting, OLEDs are becoming an increasingly interesting technology. A number of OLED materials and configurations are described in U.S. Patent Nos. 5,844,363, 6, 303, 238, and 5, 707, 745, the entire contents of each of which are incorporated herein by reference.

One method of depositing OLEDs and other organic devices is organic vapor jet printing (OVJP). The general principles of OVJP are described in U.S. Patent No. 7,404,862, issued July 29, 2008, U.S. Patent 7,744,957, issued on Jun. 29, 2010, and U.S. Patent No. 7,431,968, issued on October 7, 2008. No. 7,722,927 issued May 25, 2010, and U.S. Patent Application Serial No. 12/034,683, filed on Feb. 21, 2008, all of which are incorporated herein by reference. .

The term "organic" as used herein includes polymeric materials and small molecular organic materials that can be used to make organic optoelectronic devices. "Small molecule" means any organic material that is not a polymer, and "small molecules" can actually be quite large. In some cases, small molecules or the like may comprise repeating units. For example, the use of a long chain alkyl group as a substituent system cannot remove a molecule from the "small molecule" class. Small molecules and the like can also be incorporated into the polymer, for example, as pendant groups on the polymer backbone or as part of the backbone. Small molecules or the like can also serve as a core portion of a dendrimer composed of a series of chemical shells established on the core portion. The core portion of the dendrimer can be a fluorescent or phosphorescent small molecule emitter. Dendrimers can be "small molecules" and we believe that all dendrimers currently used in the field of OLEDs are small molecules.

As used herein, "top" means the farthest from the substrate, and "bottom" means the closest to the substrate. When the first layer is described as being "located" on the second layer, the first layer is located further from the substrate. Unless the first layer is "contacted" with the second layer, there may be other layers between the first and second layers. For example, the cathode can be described as being "located" on the anode even if there are multiple layers of organic layers in between.

Further details of OLEDs and the above definitions can be found in U.S. Patent No. 7,279,704, the disclosure of which is incorporated herein in its entirety by reference.

The present invention provides a method of depositing an organic substance. A chamber having a built-in substrate is provided. The organic substance is sprayed through a nozzle directed to the substrate: a first gas; and a vapor of the organic substance carried by the first gas is deposited on the substrate. A second gas is provided in the chamber during deposition of the organic material. The flow rate of the second gas is at least 5% of the sum of the flow rates of all gases flowing into the vacuum chamber. The second gas has a molecular weight that is at least 20% greater than the molecular weight of the first gas. The second gas system is provided in the chamber through a hole remote from the nozzle.

Preferably, the flow rate of the second gas is at least 30% of the sum of the flow rates of all gases flowing into the vacuum chamber. More preferably, the flow rate of the second gas is at least 60% of the sum of the flow rates of all gases flowing into the vacuum chamber.

Preferably, the total pressure in the vacuum chamber is between 1 mTorr and 1 Torr during the deposition of the organic material.

The first gas is preferably N ₂ . The second gas is preferably selected from the group consisting of Ar, Kr, Freon, Xe, CO ₂ and WF ₆ .

The second gas can be a single substance. The second gas may be a mixture of different gases each having a molecular weight that is at least 20% greater than the molecular weight of the first gas.

The second gas preferably has a molecular weight that is at least 100% greater than the molecular weight of the first gas. The second gas may be a mixture of materials each having a molecular weight that is at least 100% greater than the molecular weight of the first gas.

The chamber can be a vacuum chamber.

The present invention provides a method of depositing an organic substance. A chamber having a built-in substrate is provided. The organic substance is sprayed through a nozzle directed to the substrate: a first gas; and a vapor of an organic substance carried by the first gas is deposited on the substrate. A second gas is supplied to the chamber during deposition of the organic material. The second gas has a molecular weight that is at least 20% greater than the molecular weight of the first gas. The second gas system is provided in the chamber through a hole remote from the nozzle. The nozzle has a hole of the smallest size. The organic material is deposited on the substrate to form a patterned feature having a shape defined by the shape of the aperture. The partial pressure of the second gas in the chamber during deposition of the organic material is sufficient to deposit an organic layer at a minimum distance from the edge of the patterned feature relative to other identical deposits performed without the second gas The amount of substance is reduced by a factor of two.

Typically, an OLED comprises at least one organic layer between an anode and a cathode and electrically connected to an anode and a cathode. When a current is applied, the anode is injected into the hole and the cathode injects electrons into the (or other) organic layer. The injected holes and electrons each migrate toward the oppositely charged electrode. When electrons and holes are localized on the same molecule, they are formed as "excitons" of localized electron-hole pairs with excited energy states. When an exciton generates relaxation according to a light emission mechanism, it emits light. In some examples, excitons can be localized to excitons or excited complexes. Non-radiative mechanisms such as thermal relaxation may also be present, but are generally considered undesirable.

FIG. 1 shows an organic light emitting device 100. These figures are not necessarily drawn to scale. The device 100 includes a substrate 110, an anode 115, a hole injection layer 120, a hole transfer layer 125, an electron blocking layer 130, an emission layer 135, a hole blocking layer 140, an electron transport layer 145, and a An electron injection layer 150, a protective layer 155 and a cathode 160. The cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. Apparatus 100 can be made by depositing the layers in sequence. The nature and function of the various layers and the example materials are described in more detail in columns 6 to 10 of US 7,279,704, which is incorporated by reference.

More examples of each of these layers can be provided. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, the disclosure of which is incorporated herein in its entirety. An example of a p-doped type of hole-transporting layer is m-MTDATA in which a 50:1 molar ratio doping F is substituted for 4-TCNQ as disclosed in U.S. Patent Application Publication No. 2003/0230980, which is incorporated herein by reference. The full text is incorporated by reference. Examples of the emission and the host material are disclosed in U.S. Patent No. 6,303,238, the entire disclosure of which is incorporated herein by reference. An example of an n-doped electron-transporting layer is BPhen, which is doped with Li at a molar ratio of 1:1 as disclosed in U.S. Patent Application Publication No. 2003/0230980, the entire disclosure of which is incorporated herein by reference. An example of a cathode comprising a thin layer of a metal (such as Mg:Ag) and a composite cathode of an overlying transparent conductive sputter deposition type ITO layer is disclosed in U.S. Patent Nos. 5,703,436 and 5,707,745, each incorporated by reference. The theory and use of the barrier layer is described in more detail in U.S. Patent No. 6,097,147, and U.S. Patent Application Publication No. 2003/0230980, the entire disclosure of which is incorporated herein by reference. An example of an injection layer is provided in U.S. Patent Application Publication No. 2004/0174116, the entire disclosure of which is incorporated herein by reference. A description of the protective layer can be found in U.S. Patent Application Publication No. 2004/0174116, the entire disclosure of which is incorporated herein by reference.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210, a cathode 215, an emissive layer 220, a hole transfer layer 225, and an anode 230. Device 200 can be fabricated by sequentially depositing the layers. Since most common OLED configurations have a cathode on the anode and device 200 has a cathode 215 underneath anode 230, device 200 can be referred to as a "reverse" OLED. Materials similar to those described for device 100 can be used in corresponding layers of device 200. Figure 2 provides an example of how some layers may be omitted from the structure of device 100.

The simple layered structure illustrated in Figures 1 and 2 is provided by way of non-limiting example, and it should be understood that embodiments of the invention may be utilized in a variety of other configurations. The particular materials and structures described are exemplary in nature and other materials and structures may be used. Functional OLEDs can be obtained by combining the different layers in different ways, or layers can be completely omitted based on design, performance and cost factors. Other layers not explicitly described may also be included. Materials other than those specifically described may be used. While many of the examples provided herein describe that different layers comprise a single material, it should be understood that a combination of materials such as a mixture of a host and a dopant or, more generally, a mixture, can be used. Again, the layers can have different sub-layers. The meaning of the different layers in the text is not intended to be strictly limited. For example, in device 200, hole transfer layer 225 transfers holes and injection holes in emissive layer 220, and may be described as a hole transfer layer or a hole injection layer. In one embodiment, an OLED can be described as having an "organic layer" between the cathode and the anode. As described, for example, with respect to Figures 1 and 2, the organic layer can comprise a single layer or can further comprise multiple layers of a different organic material.

</ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> <RTIgt; By way of another example, an OLED having a single organic layer can be used. The OLEDs can be stacked, for example, as described in U.S. Patent No. 5,707,745, the entire disclosure of which is incorporated herein by reference. The OLED structure can deviate from the simple layered structure illustrated in Figures 1 and 2. For example, the structure may include a slanted reflective surface that is modified by an external coupling, such as the mesa structure described in U.S. Patent No. 6,091,195, the disclosure of which is incorporated herein by reference. The structure, the entire contents of which are incorporated by reference.

Any of the various embodiments may be deposited by any suitable method, unless otherwise indicated. For the organic layer, the preferred method includes, for example, the thermal evaporation in the U.S. Patent Nos. 6,013,982 and 6,087,196, which are incorporated herein by reference in their entirety, the entire disclosure of which is incorporated herein by reference. Organic vapor-deposited (OVPD) in U.S. Patent No. 6,337,102, issued to U.S. Patent No. 6,337,102, the disclosure of which is incorporated herein by reference. ) deposition. Other suitable deposition methods include spin coating and other solution based methods. The solution based process is preferably carried out under nitrogen or an inert atmosphere. For other layers, preferred methods include thermal evaporation. The preferred method of patterning includes, by way of example, mask deposition, cold soldering, and patterns associated with deposition methods such as ink jet and OVJP, as disclosed in U.S. Patent Nos. 6,294,398 and 6,468,819 each incorporated herein by reference. Chemical. Other methods are also available. The material to be deposited can be modified such that it can be compatible with a particular deposition process. For example, substituents such as branched or unbranched and preferably containing at least 3 carbon alkyl and aryl groups can be used in small molecules to enhance their ability to undergo solution processing. A substituent having 20 carbons or more of carbon and 3 to 20 carbons may be used. Materials having an asymmetric structure may have better solution treatability than symmetric ones because asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents can be used to enhance the ability of small molecules to undergo solution processing.

Devices made in accordance with embodiments of the present invention can be incorporated into a variety of consumer products, including flat panel displays, computer monitors, televisions, billboards, lamps for indoor or outdoor lighting and/or signal transmission, heads-up displays, fully transparent displays , flexible displays, laser printers, telephones, mobile phones, personal digital assistants (PDAs), laptops, digital cameras, camcorders, viewfinders, microdisplays, vehicles, large-area walls, Theater or open field screen or signal transmitter. A variety of control mechanisms, including passive matrices and active matrices, can be used to control devices made in accordance with the present invention. Many of these devices are designed for a comfortable temperature range (such as 18 ° C to 30 ° C, and better room temperature (20 to 25 ° C)).

The materials, structures, and methods described herein can be used in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can utilize such materials, structures, and methods. More generally, organic devices such as organic transistors can utilize such materials and structures.

In many cases, organic vapor jet printing (OVJP) is an ideal method for depositing organic materials. The OVJP can deposit organic molecules having a shape or pattern defined by the nozzles, without the use of masks, photoresists or similar patterning techniques based on substrate blocking or masking portions that are not desired to be deposited thereon, through which the nozzles are deposited Produce a spray.

Typically, the nozzles or nozzles of the OVJP system are in fluid communication with a carrier gas source and an organic molecular source.

As used herein, a "nozzle" is a mechanism that directs, directs, or controls a flow of material after it leaves the mechanism.

Some (though not all) OVJP systems include deposition in the chamber. Many OVJP systems also include a substrate holder that is adapted to support the substrate under the nozzle and move relative to the nozzle. The nozzle, the substrate support or both can be moved. Where a chamber is used, the nozzle and substrate support can be located within the chamber. The use of chambers allows for better control of ambient conditions such as background pressure, gas composition and temperature. As used herein, "below" the nozzle means in the direction of the nozzle (i.e., the nozzle is directed toward the substrate). The nozzle can be oriented in any number of directions of the substrate.

OVJP has in fact demonstrated the use of a single carrier gas (generally referred to as nitrogen) to deliver organic vapor to the nozzle, which is deposited on the substrate in close proximity to the nozzle, thereby obtaining a lateral dimension defined by the size of the nozzle. The film. Although it is generally stated that the width of the deposited film is equal to the size of the nozzle, less than 100% of the organic molecules ejected from the nozzle will be deposited when more complex analysis is used to show that there is no physical mask on the substrate. Below the nozzle itself. The material deposited outside the nozzle area is referred to as "overspray." Assuming that the organic device is susceptible to contamination (specifically, organic light-emitting devices are susceptible to luminescent molecules with lower excitation energies), a small amount of over-injection (<0.1%) can be problematic. Therefore, it is desirable to minimize over-injection.

A coaxial stream of non-organic gases (referred to as "protective flow") around the nozzle has been disclosed to reduce over-injection, see U.S. 7,744,957. However, this coaxial configuration increases the complexity of the OVJP nozzle. A simpler method of reducing overspray is disclosed herein by simply introducing a "filler" gas having a substantially higher atomic mass than the carrier gas in the deposition chamber.

Figure 3 shows a cross section of four different nozzle geometries taken in the direction perpendicular to the gas flow. The arrows in each hole indicate the "minimum size" of the hole. In mathematical terms, in the case of the smallest dimension, the length of the arrow is at a local maximum (for circles, ellipses, and triangles) or constant relative to the translation of the entire arrow in a direction perpendicular to the arrow (for rectangles) ), and the "minimum" size is the minimum local maximum or is constant for this point. Figure 3 shows cross sections of holes 310, 320, 330 and 340 having circular, elliptical, triangular and rectangular cross sections, respectively. For the deposition line, the rectangular hole is the optimum shape, and it is also relatively easy to obtain the shape in the nozzle which utilizes the ruthenium etching. However, other shapes can be used.

The present invention provides a method of depositing an organic substance. A chamber having a built-in substrate is provided. The organic substance is sprayed through a nozzle directed to the substrate: a first gas; and a vapor of the organic substance carried by the first gas is deposited on the substrate. A second gas is provided in the chamber during deposition of the organic material. The flow rate of the second gas is at least 5% of the sum of the flow rates of all gases flowing into the vacuum chamber. The second gas has a molecular weight that is at least 20% greater than the molecular weight of the first gas. The second gas system is provided in the chamber via a hole remote from the nozzle.

Preferably, the flow rate of the second gas is at least 30% of the sum of the flow rates of all gases flowing into the vacuum chamber. More preferably, the flow rate of the second gas is at least 60% of the sum of the flow rates of all gases flowing into the vacuum chamber.

It has been demonstrated (see Figure 5 and related discussion) that the presence of a second gas, which may be referred to as a "filler" gas, reduces the over-injection relative to a method in which only a carrier gas is present in place of the heavier fill gas. One feature of the second gas is that it is introduced into the chamber via a hole remote from the nozzle. By "away from" the nozzle, it is meant the "minimum dimension" of the at least two nozzle holes exiting the nozzle orifice through the orifice into which the gas is introduced. In most embodiments, it is highly probable that the pores through which the fill gas is introduced are further apart. The filling gas is different from the "protective flow". In its most common embodiment, the protective flow is introduced into the chamber via a ring around the nozzle through which the carrier gas is introduced, ie, the specific position at which the protective flow is introduced is related to The fluid dynamics of the gas injected by the nozzle. In its purest sense, it is irrelevant to introduce a specific location of the "filler gas" because the presence of a fill gas in the surrounding gas in the chamber affects the hydrodynamics of the gas ejected from the nozzle, resulting in a narrower jet diffusion. . Therefore, the use of a heavy fill gas can be easier to implement than using a protective flow.

By "heavy" it is meant herein that the filled (or second) gas has a molecular weight that is at least 20% greater than the carrier (or first) gas. Molecular weight is at least 20% of the lines having the desired effect as demonstrated with respect to FIG. 5 and the related experiment, the molecular weight as compared to the ₂ N of 14, Ar 18 having a molecular weight of. From the viewpoint of narrow jet diffusion, it is understood that the heavier the filling gas is, the better the carrier gas is. The molecular weight of the filling gas is preferably at least 100% greater than the molecular weight of the carrier gas.

Preferably, the fill gas is inert depending on the performance of the device. The fill gas should not react with the material of the device being fabricated. Suitable inert and heavy gases include Ar, Kr, Freon, Xe, CO ₂ and WF ₆ . N _{2 is} preferably used as the first gas because it is inert and extremely light. He can also be used as a carrier gas, which shows a new possibility of "heavier" filling gas. For example, N ₂ is heavier than He, and when He is a carrier gas, N ₂ can be used as a filling gas.

The filling gas may be a single gas that meets the weight standard, or whether it is 20% or 100% larger than the molecular weight of the carrier gas, which may be a mixture of gases each meeting the weight standard. However, for the sake of simplicity, it is preferred to use a single gas which has its intended effect because it consists of molecules that are heavier relative to the carrier gas and should be generated regardless of whether all of the filling gas molecules are the same or not. This effect.

In most embodiments, the carrier gas is desirably a single gas, preferably N ₂ . However, embodiments of the invention may be practiced with a carrier gas having multiple gas components. In this context, the "molecular weight" of the carrier gas should be considered as the molar average molecular weight.

Preferably, during deposition of the organic material, the total pressure in the vacuum chamber is between 1 mTorr and 1 Torr. Generally, it is a preferred pressure range for OVJP. Similarly, OVJP (including OVJP using a fill gas) can be implemented at high pressure and low pressure. However, pressures below the lower limit of the range are not good because OVJP is based on its nature to introduce gas into the chamber during deposition, so that a lower vacuum may be compared to a similar vacuum in other methods such as thermal evaporation. Vacuum equipment that is extremely expensive. Higher pressures can be easily utilized, but the carrier gas should generally be removed so that deposition can occur throughout the chamber for a controlled period of time and it is extremely easy to obtain a pressure of 1 Torr.

The chamber is preferably a vacuum chamber. However, there are embodiments of OVJP that can be implemented at atmospheric pressure or high pressure, and the use of a filling gas can be applied to its embodiments.

One method of quantifying the amount of gas filled in a chamber is based on the flow rate. At equilibrium, it is desirable that the relative flow rates of the different gases introduced into the chamber may correspond to the partial pressure of the gas at the location away from any of the holes in the introduced gas (i.e., the "surrounding" gas within the chamber). However, the control and measurement of the flow rate is much easier than the partial pressure.

Another method of quantifying the amount of gas filled in a chamber is the determination of the overspray effect. One object of embodiments of the present invention in the context of OLEDs is to reduce the amount of impure molecules in adjacent devices having different structures and generally emitting light of different colors. In the case where an impure molecule is emissive in a device which treats it as an impurity, the amount of impurities contained in the device is easily quantified by measuring the emitter of the device. The experiment of Figure 5 shows that a suitable amount of filler gas can easily reduce the amount of impurities relative to the presence of a fill gas therein, but the same total pressure is the same (and is due to the presence of carrier gas). Generally, nozzles suitable for OVJP can have a "minimum dimension" as described with respect to FIG. A method of quantifying whether the filling gas has a partial pressure sufficient to have a desired effect is a simple experiment in which the OVJP using the filling gas is compared with the OVJP in which only the carrier gas is present at the same total pressure. This can be achieved as described in Figure 5. The effect of overspray can be measured at a minimum size from the edge of the patterned feature. The partial pressure of the second gas in the chamber during deposition of the organic material is sufficient to deposit at a distance from a margin of the patterned feature edge relative to other identical deposits performed without the second gas The amount of organic matter is reduced by a factor of two, and it can be said that the filling gas has a remarkable effect. As illustrated in Figure 5, this effect is easily achieved by a suitable amount of fill gas.

Preferably, the OVJP is carried out at a relatively low vacuum (typically, 1 mTorr to 1 Torr), however, embodiments with higher vacuum to atmospheric pressure or higher are highly desirable. Thus, the evaluable partial pressure of the residual gas in the vacuum chamber can be observed by the organic molecules after they have been carried through the nozzle by the carrier gas. Within this limit, some combination of pressure and carrier gas flow rate results in a minimum amount of over-injection.

Embodiments of the invention include further reducing the over-injection by intentionally introducing a portion of the deposition chamber that is heavier than the carrier gas. This heavier gas can be referred to as a "filler" gas. The heavier gas is more restrictive to the carrier gas leaving the nozzle and the expansion of the organic vapor than the carrier gas. In a specific illustrative example, the carrier gas is nitrogen and the chamber is filled with a portion of the pressure of argon. The over-injection in the example where the chamber contains argon is less than measurable to the extent that the chamber contains only nitrogen introduced via the carrier gas.

There may be different than the optimum pressure of Ar using only the N ₂ gas filling the optimum total pressure, and it may be desirable that the optimum total pressure measured. The optimum total pressure can be easily measured by performing a series of depositions at different total pressures and measuring the results. This is customary for regular OVJPs without a fill gas and should be an equivalent of an OVJP with a fill gas.

If only the reduction in over-injection is considered, it is desirable to use the heaviest possible fill gas. However, in the selection of filling gas, other factors, such as cost, should be considered, and toxicity and environmental effects should also be considered. The fill gas should also be inert, ie it should not adversely react with any part of the organic device. As for the gas which is desired to be used as the filling gas due to the high molecular weight, it is preferable to include Kr, a composite gas molecule such as CF ₄ , C ₂ F ₆ and Freon, Xe, CO ₂ and WF ₆ in descending order. It is expected that the over-injection can be desirably reduced when there is a heavy fill gas compared to the same total pressure when only the carrier gas is present. However, it is contemplated that each of the packed/carrier gas combinations may have a different partial pressure that minimizes over-injection, which can be determined by relatively simple experiments.

One consideration for filling OVJP deposits with specialty gases is very likely to be cost. It is preferred to continuously introduce a new fill gas to compensate for the carrier gas exiting the nozzle, otherwise the deposition chamber will eventually be filled with only the carrier gas. This point means that a large volume of fill gas can be used over time and costs and/or disposal should be considered.

Embodiments of the invention can be implemented in a multi-dimensional range. It is desirable to use heavy ambient gas for any size of the OVJP system.

Figure 4 shows a simple single nozzle embodiment of an embodiment of the invention. FIG. 4 shows systems 410 and 450. System 410 includes a chamber 420 having an OVJP nozzle 422, a bore 424 for introducing a fill gas, and a bore 426 for removing gas from chamber 420. A vacuum system can be coupled to the aperture 426. In the case where the gas originates from a source outside the chamber, the nozzle 422 is abstractly illustrated as a jet of gas 430. It should be understood that any of a variety of known systems including nozzles for OVJP can be used. System 410 illustrates a wider spray spread in the presence of a light ambient gas.

System 450 includes a chamber 460 having an OVJP nozzle 462, a bore 464 for introducing a fill gas, and a bore 466 for removing gas from chamber 460. A vacuum system can be coupled to the aperture 466. In the case where the gas originates from a source outside the chamber, the nozzle 462 is abstractly illustrated as a jet of incoming gas 470. It should be understood that any of a variety of known systems including nozzles for OVJP can be used. System 450 illustrates a narrower jet spread with heavy ambient gas.

One dimensional array of nozzles (i.e., nozzle lines) is a preferred embodiment of the nozzle block. Such an array can achieve high throughput patterning by moving the nozzles relative to the substrate (and vice versa, in a direction perpendicular to the nozzle lines). Other configurations of multiple nozzles, such as a two-dimensional array, can also be used. A variety of nozzle shapes are available. For example, preferably, the nozzles may be elongated (e.g., rectangular) depending on the long axis in the direction of the substrate translation array.

Embodiments of the invention may generally be used in conjunction with other technical implementations of OVJP or modified OVJP. For example, embodiments of the present invention can be implemented in conjunction with an ejector in a nozzle block that causes a localized vacuum, as disclosed in U.S. Patent Application Serial No. 11/643,795, the disclosure of which is incorporated herein by reference.

Figure 5 shows a plot of the emission versus distance from the deposition edge, which provides a measure of how much over-spray occurs during deposition. Different deposition conditions exemplify the effect of heavy fill gas on OVJP deposition and, in particular, reduce over-injection by using heavy fill gas. The NPD/TPBi double layer device was obtained by vacuum thermal deposition (VTE) on a 6" glass substrate patterned with a 1 mm wide ITO anode with a 0.5 mm pitch between the lines. The charge injection and transfer characteristics of the device were highly asymmetric. As a result, all excitons generated are tightly bound to the NPD/TPBi interface. In the absence of contamination, the resulting device exhibits blue light EL from NPD. It is used in the ITO line between the deposited VTE deposits along the NPD and TPBi. One of the OVJP deposits a fine red dopant line. Since the effective exciton is transferred to the red dye, the deposition line shows red electro-excitation light. Any over-spraying of the red dye at the far side of the deposited ITO strip may also be deposited according to The amount of red dye at the position shows a certain degree of red light emission. The peaks in the spectrum of the electro-excitation light are significantly independent due to the red dye and the preset NPD emission, and the ratio of the red and blue peaks is quantitatively defined. The amount of red dye; this ratio is calibrated using controlled VTE deposition of the test structure. Due to the effective limitation of excitons at the organic heterointerface and the high efficiency of energy transfer over time, such The structure is extremely prone to over-spray and has been used to detect <0.25 The material or a single layer of about 1/10.

The experimental configuration is somewhat limited. Illustratively, the fabrication of the device OVJP portion is accomplished in a chamber such as the chamber illustrated in FIG. The chamber is a vacuum chamber, but the vacuum is not of variability - that is, the vacuum is opened or closed without setting conditions therein. Assuming that the vacuum is open, the total pressure in the chamber is measured based on the flow rates of the carrier gas and the fill gas. The chamber has a single pressure measuring device that measures the total pressure within the chamber.

The different plots of Figure 5 are as follows: 0.1 Torr N ₂ represents the calibration operation to determine the total pressure (0.1 Torr) for setting the carrier gas flow rate to a specific amount, and the only gas entering the chamber is the carrier gas passing through the nozzle. . This plot shows that there is less over-spray because the total pressure is less, but is not similar to other plots for the purpose of determining whether the surrounding gas is the same as the carrier gas or including the effect of a heavier fill gas. For the two plots where N ₂ is 0.3 Torr, the Ar fill is the same experiment in which the flow rate of the N ₂ carrier gas is the same as the flow rate of 0.1 Torr of N ₂ , but the Ar gas also enters the chamber via a hole away from the nozzle. The flow rate of Ar is sufficient to achieve a total pressure of 0.3 Torr. For the two plots where N ₂ is 0.3 Torr, the N ₂ fill is the same experiment, which is performed in the same manner as the Ar fill experiment, except that N ₂ gas is introduced into the chamber instead of Ar gas via a hole away from the nozzle. Outside the total pressure of 0.3 Torr. Data show that at the same pressure, as compared to using a preset filling N _2, Ar 0.3 torr of less filled so that excessive injection.

The minimum amount of overspray shown in Figure 5 is suitable for calibration operations in the absence of fill gas. The filling gas to both the results are shown compared to the use of the predetermined N ₂ filled in the deposition under the 0.1 Torr, more excessive injection. However, due to the limited nature of the experimental instrument, 0.1 Torr is the minimum achievable pressure to increase the pressure through the nozzle and any fill gas, so the limited instrument can be used to test the Ar fill at a total pressure of 0.1 Torr. Compared to 0.3 Torr of N ₂ (Ar-filled), the relevant control is 0.3 Torr of N ₂ (N ₂ filled), which is shown at the same pressure, with respect to the lighter ambient gas, heavier ambient gas ( Or, moreover, the excess gas is reduced due to the generation of at least a significant partial pressure of the gas by the heavy gas. This is true even in the case where heavy gas is present in the chamber through a hole remote from the nozzle.

It should be understood that the various embodiments described herein are by way of example only, and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted by other materials and structures without departing from the spirit of the invention. Thus, the invention as claimed may include variations of the specific examples and preferred embodiments described herein. It should be understood that the different theories of the operation of the invention are not intended to be limiting.

100. . . Organic light emitting device

110. . . Substrate

115. . . anode

120. . . Hole injection layer

125. . . Hole transfer layer

130. . . Electronic barrier

135. . . Emissive layer

140. . . Hole barrier

145. . . Electron transfer layer

150. . . Electron injection layer

155. . . The protective layer

160. . . cathode

162. . . First conductive layer

164. . . Second conductive layer

200. . . Reverse OLED

210. . . Substrate

215. . . cathode

220. . . Emissive layer

225. . . Hole transfer layer

230. . . anode

310. . . hole

320. . . hole

330. . . hole

340. . . hole

410. . . system

420. . . Chamber

422. . . nozzle

424. . . hole

426. . . hole

430. . . gas

450. . . system

460. . . Chamber

462. . . nozzle

464. . . hole

466. . . hole

470. . . gas

Figure 1 shows an organic light emitting device.

Figure 2 shows a reverse organic light-emitting device without different electron-transport layers.

Figure 3 shows a cross section of four different nozzle geometries taken in a direction perpendicular to the gas flow.

Figure 4 shows two chambers for material deposition, one with light ambient gas and the other with heavy ambient gas.

Figure 5 shows a plot of the emission versus distance from the deposition edge, which provides a measure of how much overspray occurs during deposition.

410. . . system

420. . . Chamber

422. . . nozzle

424. . . hole

426. . . hole

430. . . gas

450. . . system

460. . . Chamber

462. . . nozzle

464. . . hole

466. . . hole

470. . . gas

Claims (12)

A method for organic vapor jet printing, comprising: providing a chamber having a built-in substrate; spraying through a nozzle guided to the substrate: a first gas; and a vapor of an organic substance carried by the first gas to cause an organic substance Depositing on the substrate; providing a second gas in the chamber during deposition of the organic substance; wherein the flow rate of the second gas is at least 5% of a total flow rate of all gases flowing into the vacuum chamber; the second gas Having a molecular weight that is at least 20% greater than the molecular weight of the first gas; and the second gas system is provided in the chamber through a hole remote from the nozzle. The method of claim 1, wherein the flow rate of the second gas is at least 30% of a sum of flow rates of all gases flowing into the vacuum chamber. The method of claim 1, wherein the flow rate of the second gas is at least 60% of a sum of flow rates of all gases flowing into the vacuum chamber. The method of claim 1, wherein the total pressure in the vacuum chamber is between 1 mTorr and 1 Torr during the deposition of the organic material. The method of claim 1, wherein the first gas is N ₂ . The method of claim 1, wherein the second gas system is selected from the group consisting of Ar, Kr, freons, Xe, CO ₂ and WF ₆ . The method of claim 1, wherein the second gas is a single substance. The method of claim 1, wherein the second gas has a first gas The molecular weight is at least 100% greater than the molecular weight. The method of claim 1, wherein the second gas is a mixture of materials each having a molecular weight greater than 20% greater than the molecular weight of the first gas. The method of claim 1, wherein the second gas is a mixture of materials each having a molecular weight greater than 100% greater than the molecular weight of the first gas. The method of claim 1, wherein the chamber is a vacuum chamber. A method for organic vapor jet printing, comprising: providing a chamber having a built-in substrate; spraying through a nozzle guided to the substrate: a first gas; and a vapor of an organic substance carried by the first gas to cause an organic substance Depositing on the substrate; providing a second gas in the chamber during deposition of the organic substance; wherein the second gas has a molecular weight that is at least 20% greater than a molecular weight of the first gas; the nozzle has a hole having a minimum size The organic material is deposited on the substrate as a patterned feature having a shape defined by the shape of the hole; the chamber is deposited during deposition of the organic substance relative to other identical depositions performed without the second gas The partial pressure of the second gas is sufficient to reduce the amount of organic material deposited at a distance from a minimum dimension of the edge of the patterned feature by a factor of two.