HK1052272A - Encapsulation of organic electronic devices - Google Patents

Description

Encapsulation of organic electronic devices

Technical Field

The present invention relates to organic polymer based electronic devices such as diodes, e.g. light emitting diodes and photodiodes. More particularly, the present invention relates to the fabrication processes and structures of such devices, which result in high device efficiency and promote a long service life that is acceptable to the market.

Background

Solid state electronic devices fabricated with conjugated organic polymers have attracted attention. Diodes based on conjugated polymers, in particular Light Emitting Diodes (LEDs) and photodiodes, are particularly attractive due to their possibility of application in display and sensor technology. These related documents, as well as other articles, patents, and patent applications, are incorporated herein by reference.

The structure of such devices comprises a coating or film of an electro-optically active conjugated organic polymer bonded to the opposite electrodes (anode and cathode) and supported on a solid substrate.

In general, materials for use as the active layer in polymer diodes, particularly LEDs, include semiconducting conjugated polymers, such as, for example, photoluminescent semiconducting conjugated polymers. In certain preferred embodiments, the polymer is a semiconducting conjugated polymer that is photoluminescent and capable of being dissolved and processed from solution into a uniform film.

The anode of such organic polymer-based electronic devices is typically composed of a higher work function metal and a transparent, non-stoichiometric semiconductor such as indium/tin-oxide. The role of this anode is to inject holes into the otherwise filled pi-bands of the light-emitting polymer of the semiconductor.

Lower work function metals such as barium and calcium are preferred as cathode materials in a variety of configurations. Ultra-thin layers of such low work function metals and their oxides are preferred. The role of this low work function cathode is to inject electrons into the otherwise empty pi-bands of the semiconducting light emitting polymer. The holes injected from the anode and the electrons injected from the cathode are combined in the active layer in a light-emitting manner and light is emitted.

Although low work function materials are required for efficient electron injection from the cathode and satisfactory device performance, unfortunately, low work function metals such as calcium, barium, strontium, and their oxides are typical chemically reactive species. They react readily with oxygen and water vapor at room temperature and are more vigorous at high temperatures. Such reactions deteriorate their required low work function properties, degrading the critical interface between the cathode material and the light emitting semiconducting polymer. This is a long-term problem leading to a rapid decrease in the efficiency (and light output) of the device element during storage and during stress, especially at high temperatures.

Solid state devices based on other organic polymers suffer from similar stability problems. The photosensitive devices and the array structures of the devices and the materials used are very similar to those found in polymer-based LEDs. The main difference between polymer based LEDs and photosensors is that very reactive low work function electrodes need not be employed, and the electrodes are often of opposite polarity. However, moisture and oxygen react with components of such devices, which in turn degrades the performance of the devices over time.

One approach to reducing the deleterious effects of atmospheric exposure is to enclose the device in a barrier, isolating the active material from moisture. This approach has met with some success, but it is not always adequate to address the problems caused by small amounts of moisture trapped inside the encapsulation or diffusing in over time.

Kawami et al, in U.S. patent 5,882,761, disclose a method of packaging a light emitting device fabricated using a thin film of light emitting organic molecules as the active layer, which is intended to address the problem of water contamination. The patent describes the placement of a solid compound, such as sodium oxide, that is reactive with water in the encapsulation of the component. Such reactive compounds covalently react with the water in the encapsulation and convert the water to a solid product. For example, sodium oxide as mentioned reacts with water to produce solid sodium hydroxide. This patent describes that it utilizes these water-reactive compounds to remove water in order to retain moisture at elevated temperatures. Kawami et al teach that materials that physically absorb moisture cannot be used because moisture can evolve at high temperatures (e.g., 85℃.).

The water-reactive solid state compounds in the Kawami patent are themselves strongly reactive, thereby rendering the reaction products thereof also strongly reactive. Accidental contact of these compounds or reaction products with other components of the device or components of the device encapsulation may therefore pose a hazard, and there is a need for a method of encapsulating solid state electronic devices based on organic polymers that is sufficient to prevent diffusion of water vapor and oxygen into the device, thereby preventing limited lifetime.

Furthermore, many known methods for achieving hermetic electronic devices require heating the device to temperatures above 300 ℃ during the encapsulation process. Most polymer-based light emitting devices cannot withstand such high temperatures.

Brief description of the invention

The present invention relates to an electronic device comprising a polymer electronic device comprising a pair of electrodes disposed opposite to each other and an active polymer layer disposed between the electrodes; an air-tight enclosure having an interior surface adjacent the polymeric electronic device and an opposing exterior surface adjacent the external atmosphere; a desiccant adjacent the interior surface, the desiccant having a pore structure and being capable of drawing water into the pore structure thereof by physical absorption; wherein the hermetic enclosure seals the polymer electronic device from the external atmosphere with the polymer electronic device and the desiccant. The present invention also relates to a method of manufacturing an increased lifetime polymer electronic device that is packaged in a solid desiccant-containing hermetic enclosure.

In a preferred embodiment, the desiccant is incorporated into one or more layers of the substrate supporting the polymer electronic device.

As used herein, the phrase "adjacent" does not necessarily mean that one layer is directly adjacent to another layer, but rather means that a first surface location is proximate (e.g., the desiccant is proximate to an interior surface thereof) when compared to a second surface (e.g., an exterior surface) opposite the first surface.

Brief Description of Drawings

FIG. 1 shows a cross-section of a representative device of the present invention;

FIG. 2 shows the effect of different dry materials on the lifetime of an encapsulated device at 85 ℃ and ambient humidity;

FIG. 3 shows the water removal efficiency of the present invention compared to the removal efficiency of materials and methods used in the prior art; and

FIG. 4 shows the stability of the water removal by the process of the present invention compared to the process used in the prior art.

Description of the preferred embodiments

As best seen in fig. 1, the electronic device 100 of the present invention includes a polymer electronic device 110 comprised of an anode 112 and a cathode 114 with associated leads 116, 118, an electroactive organic polymer layer 120, and in this embodiment, a substrate 122. The device 110 also includes an enclosure 124 that separates the electronic device from the atmosphere. The enclosure is based on a substrate 122 with a lid or cover 126 which is secured to the substrate 122 by an adhesive 128. The desiccant 130 is enclosed in the cartridge 124 and is preferably secured to the inner surface 132 of the cartridge by an adhesive 134. Substrate

The substrate 122 is generally impermeable to air and moisture. In a preferred embodiment, the substrate is glass. In a second preferred embodiment, the substrate is silicon. In a third preferred embodiment, the substrate is a flexible substrate, such as a gas impermeable plastic or composite material containing a combination of inorganic and plastic materials. Examples of useful flexible substrates include sheets or multi-layer laminates of flexible materials such as impermeable flexible plastics such as polyesters, for example polyethylene terephthalate, or composites of a plastic sheet and an optional metallic or inorganic dielectric layer deposited thereon. In a preferred embodiment, the substrate is transparent (or translucent) to allow light to enter the encapsulation area or to allow light to be emitted to pass through the encapsulation area. Packaging box

The polymer electronics 110 are sealed from the atmosphere by a hermetic enclosure 126. How the hermetic enclosure is made is not critical as long as the process steps do not adversely affect the components of the polymer electronic device 110. For example, the airtight box 126 may be composed of a plurality of plates bonded together with an adhesive. In a preferred embodiment, the hermetic enclosure comprises a cover 126 bonded to a base plate. As best seen in fig. 1, the preferred substrate 122 is a substrate for the polymer electronic device 110.

The material used to form the airtight box 126 should be impermeable to air and moisture. In one embodiment, the cover is made of metal. In another embodiment, the cover is made of glass or of a ceramic material, and air and water impermeable plastics may also be used.

The thickness of the cap 126 is not critical to the present invention, so long as the thickness of the cap is sufficient to form a continuous barrier (no voids and no pinholes). The thickness of the cap 126 is preferably between 10 and 1000 μm. In the case where the substrate is not a polymer electronic device substrate (not shown), it is envisioned that the base may be made of the same material as the cap. As best seen in fig. 1, the cap 126 is sealed to the substrate 122 by an adhesive 128. The adhesive should be cured at a temperature below the decomposition temperature of the activation layer 120, for example, less than 75 c, preferably less than 50 c, preferably at room temperature or at an intermediate temperature. This is advantageous because it does not encounter the high temperatures common in the prior art that often damage or degrade the electronic device 110. Preferred adhesives include epoxy resins which cure under ultraviolet light irradiation or at the above-mentioned moderate temperatures (or under both actions). As best seen in fig. 1, leads 116, 118 extend from the device. The leads should be similarly sealed with adhesive 128, but functionally equivalent lead structures may be used. Solid desiccant

A solid desiccant (desiccant material) 130 is inserted before the cap 126 is sealed to the substrate 122 and the electronic device 110 is packaged. The shape of the desiccant is not critical. For example, the desiccant may be in the form of a porous packed powder, a tablet, a solid contained in a gel, a solid encapsulated in a cross-linked polymer, and/or a film. The desiccant may be placed in the enclosure 124 in various ways. For example, the desiccant 130 may be applied to a coating on the substrate or the inside surface of the cover (not shown), or, as is apparent from FIG. 1, the desiccant 130 may be secured to the inside surface 132 of the enclosure 124 with an adhesive 134. Additionally (not shown) a desiccant may be added to the flexible substrate of the electronic device or to one or more layers of a multi-layer substrate or a laminated substrate.

The nature of the solid desiccant is important. It is a porous solid, most commonly an inorganic solid with a controlled pore structure, into which water molecules can enter, but in which water molecules are physically absorbed and appear to be trapped and not released into the environment of the enclosure. Molecular sieves are one such material. In a preferred embodiment, the desiccant encapsulated in the sealed package is a zeolite. Zeolites are well known materials and are commercially available. In general, any zeolite can be used to trap water. Zeolites are known to be composed of nearly equal amounts of aluminum and silicon oxides with sodium as the counter ion. The zeolite material absorbs moisture by physical absorption rather than by chemical reaction. Physical absorption is preferred.

In a more preferred embodiment, the desiccant 130 encapsulated in the package is a zeolite material known as Tri-Sorb (sold by Sud-Chemie development packaging company, a member of the Sud-Chemie group, division of United catalysts Co., Ltd., located at Belen, New Mexico). The structure of Tri-Sorb consists of nearly equal amounts of oxides of aluminum and silicon with sodium as the counter ion. Tri-Sorb to physically absorb moisture. Significant improvements in the stability and lifetime of polymer LEDs when packaged using the methods described herein can be seen in the examples. In particular, the incorporation of physically adsorbed zeolite materials as desiccants is significantly superior to barium oxide, which is chemically adsorbed to moisture.

The amount of desiccant to be added is such as to provide sufficient capacity to trap moisture within the absorbent package when sealed. The water absorption capacity of a desiccant is a known property. The internal volume of the device and the air humidity within the package are easily determined. By varying these factors, a sufficient amount of desiccant can be determined and added.

In a preferred approach, more than a calculated amount of desiccant may be added to counteract the amount of residual water vapor that enters the active device region through an imperfect edge seal and/or residual permeability through the substrate. Active layer

A promising material for the active layer 120 in the electronic devices protected by the present invention, such as polymer LEDs, is poly (phenylene vinylene), PPV, and soluble derivatives of PPV, such as poly (2-methoxy-5- (2' -ethyl-hexyloxy) -1, 4-phenylene vinylene), MEH-PPV, a semiconducting polymer with, for example, an energy gap > 2.1 eV. U.S. patent No.5,189,136 describes this material in more detail. Another material described as useful in the present invention is poly (2, 5-bis (cholestaxy) -1, 4-phenylenevinylene), i.e., BCHA-PPV, a semiconducting polymer with an energy gap > 2.2 eV. Such materials are more closely described in U.S. patent application Ser. No.07/800,555. Other suitable polymers include, for example, poly (3-alkylthiophenes) reported by d.braun, g.gustafsson, d.mc Branch and a.j.heeger in j.appl.phys (journal of applied physics) 72, 564(1992) and related derivatives reported by m.berggren, o.inganas, g.gustafsson, j.rasmusson, m.r.anderson, t.hjberrtg and o.wennerstrom; g.grem, g.leitzkg, b.ullrich and G leisting poly (p-phenylene) reported in adv.mater, (contemporary materials) 4, 36(1992), and z.yang, i.sokolik, F.E, soluble derivatives thereof reported by Karasz in Macromolecules, 26, 1188(1993), polyquinolines reported by i.d.parker in j.appl.phys.appl.phys.lett. (applied physics, applied physics communications) 65, 1272 (1994). Blends of conjugated semiconducting polymers in non-conjugated host polymers are also useful as active layers in polymer LEDs, and are reported in c.zhang, h.von seggoem, k.pakbaz, b.kraabel, h.w.schmidt and a.j.heeger, synth.met., (synthetic materials) 62, 35 (1994). Blends comprising two or more conjugated polymers are also available, and are reported by h.nishino, g.yu, T-a.chen, r.d.rieke and synth.met of a.j.heeger (synthetic materials), 48243 (1995). In general, materials used as active layers in polymer LEDs include semiconducting conjugated polymers, more specifically semiconducting conjugated polymers that exhibit photoluminescence, and even more specifically semiconducting conjugated polymers that exhibit photoluminescence and are soluble and can be converted from solution to a uniform thin film. High work function anode

Suitable higher work function metals for use as the anode material 112 are transparent conductive films of indium/tin-oxide [ h.burroughs, d.d.c.bradley, a.r.brown, r.n.marks, k.mackay, r.h.friend, p.l.burns, and a.b Holmes, Nature 347, 539 (1990); braun and a.j.heeger, appl.phys.lett. (applied physical communication) 58, 1982(1991) ]. In addition, thin films of conductive polymers may also be used, such as those described by g.gustafsson, y.cao, g.m.treacy, f.klavetter, n.colanderi, and a.j.heeger, Nature (Nature), 357, 477 (1992); y.yang and a.j.heeger, appl.phys.lett. (using physical communication) 64, 1245(1994) and U.S. patent application serial No.08/205,519; y.yang, e.westerweele, c.zhang, p.smith and a.j.heeger, j.appl.phys. (journal of applied physics) 77, 694 (1995); j.cao, a.j.heeger, j.y.lee and c.y.kim, synth.met. (synthetic materials) 82, 221(1996) and y.cao, g.yu, c.zhang, r.menon and a.j.heeger, appl.phys.lett, (applied physical communication) 70, 3191 (1997). A two-layer anode comprising an indium/tin-oxide film and a polyaniline film in emeraldine salt form is preferred because as transparent electrodes, both materials enable light emitted from the LED to radiate from the device at effective levels. Low work function cathode

Lower work function metals suitable as cathode material 114 are alkaline earth metals such as calcium, barium, strontium and rare earth metals such as ytterbium. Alloys of low work function metals, such as alloys of magnesium in silver and alloys of lithium in aluminum, are also well known in the art (U.S. Pat. Nos. 5,047,687; 5,059,862 and 5,408,109). The thickness of the electron-injecting cathode layer is in the range of 200-5000 , as demonstrated in the prior art (U.S. Pat. Nos. 5,151,629, 5,247,190, 5,317,167 and J.Kido, H.Shionoya, K Nagai, appl.Phys.Lett. (applied physical communication), 67(1995) 2281). The lower limit of 200-500 angstroms () is required for the formation of a continuous film (full coverage) of the cathode layer (U.S. Pat. No.5,512,654; J.C. Scott, J.H. Kaufman, P.J.Brock, R.DiPietro, J.Salem, and J.A. Goitia, J.appl.Phys. (journal of applied Physics), 79(1996) 2745; I.D. Parker, H.H.Kim, appl.Phys.Lett. (applied Physics.), 64(1994) 1774). In addition to good coverage, it is believed that a thicker cathode layer can provide self encapsulation to separate oxygen and water vapor from the active components of the device.

Electron-injected cathodes containing ultrathin layers of the alkaline earth metals calcium, strontium and barium have been reported for high brightness and high efficiency polymer light emitting diodes. Ultra-thin layer alkaline earth metal cathodes with a thickness of less than 100  have a significant improvement in stability and lifetime over polymer light emitting diodes compared to conventional cathodes made of the same metal (and other low-emission functional metals) with a film thickness of greater than 200  (y.cao and g.yu, U.S. patent application 08/872,657).

For polymer light emitting diodes with high brightness and high efficiency, electron injection cathodes containing ultrathin layers of oxides of the alkaline earth metals calcium, strontium and barium have also been reported (y. cao et al PCT application No. us99/23775, filed 10/12/1999).

The structures and materials used for the photosensitive devices and device arrays are very similar to the fabrication of polymer-based LEDs. The main difference between polymer based LEDs and photosensors is that no reactive low work function electrodes need to be used and the electrodes are reversed in polarity. Long-lived photosensitive devices made with conductive polymers require hermetic packaging. Thus, the enclosure of the present invention is also useful for such devices, the encapsulation being sufficient to prevent the diffusion of water vapor and oxygen into the device, and not limiting its lifetime.

The invention will be further elucidated with reference to the following examples. These examples are merely illustrative of various embodiments of the invention and are not to be construed as limiting the invention.

Example 1

A zeolite-based desiccant (Tri-Sorb) was used as the desiccant. A polymer Light Emitting Diode (LED) array is employed as an example of a polymer-based electronic device.

An air and water impermeable cover made of glass, comprising a sheet consisting of zeolite (available from Sud-Chemie development packaging company, members of the Sud-Chemie group, division of United catalysts Co., Ltd., located at Belen, New Mexico) with which the LED array is encapsulated so that it is isolated from the atmosphere.

The desiccant is sealed in a package, and fixed to the inner surface of the impermeable cover with a thermosetting epoxy resin (Araldite 2014, Ciba specialty Chemicals, East Lansing, Michigan) as an adhesive,

the desiccant is in the form of a powder pellet. The impermeable cover is attached to the substrate with an adhesive. The structure 100 of the entire device is shown in fig. 1. The cover was sealed to the glass substrate using Araldite 2014 as an adhesive.

Immediately after the package was sealed, the size of the light emitting pixels was measured. The packaged device was then placed in an ambient humidity oven at 85 ℃ for an extended period of time. At 50-hour intervals, the devices were removed from the oven and the pixel size was measured. The deterioration of the polymer electronic device due to moisture and oxygen effects was quantified by the loss of active region. In this embodiment, the loss of the light emitting area of a pixelated LED display is measured. As shown in fig. 2, Tri-Sorb caused less than 2% loss of light emitting area after 300 hours of storage at 85 ℃.

Also, as shown in FIG. 2, the zeolite-based desiccant (in this particular example using the trade name Tri-Sorb) is clearly superior to other examples, such as BaO and CaSO₄(which is an effective desiccant material previously employed in the art) (U.S. Pat. No.5,882,761). This example shows that zeolite-based desiccants can be very effective desiccants even at high temperatures.

Example 2

The experiment of example 1 was repeated in this example, except that the storage conditions were changed to include a high humidity, i.e., 85 deg.C/85% relative humidity. As shown in fig. 3, the polymer device lost 5% of the emitter region after 300 hours.

It can also be seen from figure 3 that the zeolite system is superior to many other desiccants including BaO and CaO (which are the effective desiccant materials in the prior patents, U.S. patent No.5,882,761).

This example shows that zeolite-based desiccants are very effective desiccants even in high temperature, high humidity environments.

Example 3

This example repeats the experiment of example 1, except that the desiccant is in powder form in a porous pouch and is secured to the inner surface of an impermeable cover with an adhesive. The loss of the emission area and comparison are shown in fig. 2 and 3.

This example shows that the specific physical shape of the desiccant is not important.

Example 4

This example conducted a thermogravimetric weight loss study of Tri-Sorb and BaO to compare their performance in durably removing water from electronic device packages. Standard calibrated thermogravimetric analysis equipment was used. The Tri-Sorb and BaO tablets were heated in dry air (from room temperature to 400 ℃) while continuously monitoring the quality of the tablets and no hysteresis was observed.

The results are shown in FIG. 4. Both samples absorbed moisture at room temperature. When it is heated, the sample weight is reduced due to the thermodynamic process both releasing water. However, it can be seen that the water released by Tri-Sorb is smaller. At 85 ℃, the Tri-Sorb sample released three times less water than the BaO sample.

This example shows that Tri-Sorb has better water retention properties at high temperatures than BaO (which is a specific agent applied by Pioneer as a good desiccant at 85 ℃).

As can be seen from the above description, the present invention provides a technique for encapsulating a polymer light emitting device at the lowest possible process temperature. The encapsulation method facilitates providing a seal between the device and ambient air which may be harmful moisture and oxygen. In addition, the total thickness of the device brought by the packaging of the device by the packaging method is not increased obviously. Again, the present encapsulation method requires fewer individual process steps than methods of the currently known art.

Claims (26)

1. An electronic device (100) comprising:

a polymer electronic device (110) comprising a pair of electrodes (112, 114) opposed to each other and an active polymer layer (120) interposed between the electrodes;

a hermetically sealed pouch (124) having an interior surface (132) adjacent the polymer electronics and an opposite exterior surface adjacent the outside atmosphere;

a desiccant (130) adjacent the interior surface, the desiccant having a porous structure and capable of capturing water by physical absorption into the porous structure;

wherein the hermetic package box encapsulates the polymer electronic device such that the polymer electronic device and the desiccant are isolated from the external atmosphere.

2. A method of fabricating a long-lived organic polymer-based electronic device, comprising:

providing a polymeric electronic device (110) having a pair of electrodes (112, 114) opposed to each other and an active polymer layer (120) disposed between the electrodes;

the polymer electronic device is packaged in an air-tight enclosure (124) with a solid desiccant (130) having a porous structure capable of capturing water by physical absorption and allowing it to enter the porous structure, the enclosure separating the device and desiccant from the outside atmosphere.

3. The electronic device of claim 1 and/or the method of claim 2, wherein the polymer electronic device comprises a substrate having at least one substrate layer to incorporate a solid desiccant into one or more layers of the at least one substrate layer.

4. The electronic device of claim 1 and/or the method of claim 2, wherein the drying agent is a molecular sieve.

5. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant comprises a zeolite.

6. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant comprises Trisorb.

7. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant present in the packaging box is spaced apart from the electrodes and the polymer layer.

8. The electronic device of claim 1 and/or the method of claim 2, wherein a desiccant is present on a surface within the hermetically sealed package.

9. The electronic device of claim 1 and/or the method of claim 2, wherein the polymer electronic device further comprises a substrate supporting the polymer layer and the electrode, wherein the drying agent is present on a surface of the substrate.

10. The electronic device of claim 1 and/or the method of claim 2, wherein a desiccant is attached to a surface within the hermetically sealed package

11. The electronic device of claim 1 and/or the method of claim 2, wherein a desiccant is adhered to a surface within the hermetic package.

12. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant is present in the form of a pellet.

13. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant is present in the form of a powder contained in a porous pouch.

14. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant is present in the form of a solid contained in a porous gel.

15. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant is present in solid form contained within the membrane.

16. The electronic device of claim 1 and/or the method of claim 2, wherein the desiccant is present in solid form contained in the binder.

17. The electronic device of claim 1 and/or the method of claim 2, wherein the counter electrode comprises an anode and a cathode, the cathode comprising a water reactive low work function metal or metal oxide.

18. The electronic device of claim 1 and/or the method of claim 2, wherein the counter electrode comprises an anode and a cathode, the cathode comprising a water reactive low work function alkaline earth metal or metal oxide.

19. The electronic device of claim 1 and/or the method of claim 2, wherein the pair of electrodes comprises an anode and a cathode, the cathode comprising a water-reactive material selected from the group consisting of calcium, barium, strontium, calcium oxide, barium oxide, and strontium oxide.

20. The electronic device of claim 1 and/or the method of claim 2, wherein the polymer electronic device is a light emitting diode.

21. The electronic device of claim 1 and/or the method of claim 2, wherein the polymer electronic device is a photosensitive detector.

22. The electronic device of claim 1 and/or the method of claim 2, wherein the hermetic enclosure is comprised of a plurality of components bonded with an adhesive.

23. The electronic device of claim 1 and/or the method of claim 2, wherein the adhesive is a low temperature adhesive.

24. The electronic device of claim 1 and/or the method of claim 2, wherein the low temperature adhesive is an epoxy.

25. The electronic device of claim 1 and/or the method of claim 2, wherein the hermetic enclosure comprises a substrate bonded to a lid.

26. The electronic device of claim 1 and/or the method of claim 2, wherein the polymer electronic device further comprises a substrate supporting the polymer layer and the electrode, wherein the hermetically sealed enclosure comprises a substrate bonded to the lid and the substrate is used as the substrate.