JP2015029098A - Light emission electrochemical cell and system, use thereof, and method for operating them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emission electrochemical cell that has a long lifetime and can efficiently emit light.SOLUTION: A light emission device has a first electrode 11, a second electrode 12, and a light emission active material 13 which comes into contact with the first and second electrodes to separate them. The device includes a combination of a conjugate polymer and an electrolyte, which includes ions to enables electrochemical doping with the conjugate polymer. The ratio of the ions and conjugate polymer is so selected as to form: (i) a doped region for each electrode interface (enabling injection and transport of an electron charge carrier to and via the doped region with a zero or low overvoltage); (ii) and an effective undoped region separating the doped region (where the injected electron charge carrier can be recombined by excitation of the conjugate polymer and the polymer can be deexcited by light emission).

Description

TECHNICAL FIELD The present disclosure relates to light emitting devices based on conjugated polymers with mixed mobile ions as the active material disposed between two electrodes, which allows for a long operating life and efficient light emission. This light-emitting device can be manufactured in a flexible form on a flexible substrate.

Background The vision of simultaneous efficient, durable, flexible, and low-cost light-emitting devices is very attractive from both the end-user and manufacturer's perspective, but at the same time has been effectively resolved at the same time. Raises important scientific and technical challenges that remain untouched. Emerging fluorescing fluorescent organic semiconductors, in contrast to their more common inorganic counterparts, can be processed in a relatively simple manner at low temperatures, as such using a flexible substrate and low Suitable for cost roll-to-roll manufacturing. Thus, light emitting devices based on organic semiconductors in the form of small molecules (SM) or conjugated polymers (CP) have attracted enormous scientific and economic interests, and the current main focus is organic light emitting diodes (OLEDs). ).

  SM-based OLEDs exhibit interesting properties in that the properties of the active material can be tuned by controllable chemical doping of various layers inside the multilayer stack, and the performance of such well-designed devices has recently been quite impressive. Has reached. However, the significant drawbacks associated with SM-based OLEDs are that they are typically not suitable for solution processing and roll-to-roll manufacturing, with associated disadvantages in manufacturing simplicity and cost. On the other hand, CP-based OLEDs are compatible with simple and low-cost solution processing of polymer active materials, but suffer from the fact that in practice doping cannot be realized. As a result, to achieve good device performance, it is necessary to use a low work function, highly reactive cathode material in CP-OLED, which is negative to the function of the device from a manufacturing and stability perspective. Has an effect.

  An alternative (and often overlooked) organic light emitting device is a light emitting electrochemical cell (LEC). Its unique behavior is based on the fact that mobile ions are intimately mixed with the organic semiconductor and that these ions are redistributed during device operation to allow injection, transport and recombination of electronic charges. Yes. In addition, CP-based LECs can be processed directly from solution using potentially inexpensive materials (based on common elements such as C, H, O, N, etc.) and thus the future outlined in the first It provides most of the demand for high performance light emitting devices. However, a significant drawback to current generation in LECs, which streamlines current limited interest from industry and academia, is associated with inadequate operating life.

  There are prior arts in the field of functional LEC with long lifetime, high power conversion efficiency, and / or flexible design.

  US2008 / 0084158 and Shao, Y., GC Bazan, and AJ Heeger, Long-lifetime polymer light-emitting electrochemical cells, Advanced Materials, 2007. 19 (3): p. 365- + Discloses a significant operating lifetime for LEC devices of 100-1000 hours. They disclose dilute electrolyte components (ionic liquids) in the active material. However, these disclosures are based on the theory that phase separation has a very restrictive effect on LEC lifetime. According to these disclosures, the improved lifetime is due to the fact that the two constituents in the active material (ionic liquid and conjugated polymer) form a single phase because they are both hydrophobic.

Cao, Y., et al., Efficient, fast response light-emitting electrochemical cells: Electroluminescent and solid electrolyte polymers with interpenetrating network morphology “Efficient, fast response light-emitting electrochemical cells: electroluminescence with interpenetrating network morphology” St. and Solid Electrolyte Polymers ", Applied Physics Letters, 1996. 68 (23): p. 3218-3220., In the case of adding a surfactant to an active material mixture based on {MEH-PPV + PEO + LiCF ₃ SO ₃ }. A similar “single phase” approach is disclosed. They have achieved LEC devices with a significant brightness and an operating life of about 100 hours. Importantly, the authors use conventional high concentrations of LiCF ₃ SO ₃ salt and ion-soluble and ion-transporting PEO polymers.

Active material comprising a hydrophobic conjugated polymer (here, the salt KCF ₃ SO ₃ blended with an ion-soluble and ion-transporting solid solvent PEO) blended with a dilute hydrophilic electrolyte studied herein There appears to be little prior art in the field of LED devices having a mixture (forming a phase separated active material).

  deMello, J. C, et al., Ionic space-charge effects in polymer light-emitting diodes, Physical Review B, 1998. 57 (20): p. 12951-12963. Disclose low concentrations of salt in some of their LEC devices, but keep the concentration of ionic soluble and ion transportable solid solvents high, and therefore the total electrolyte content is high. Furthermore, this disclosure focuses on the operating mechanism of the device and does not report any data, for example, regarding operating lifetime.

State-of-the-art OLEDs that simply include MEH-PPV as the active material and have a power conversion efficiency of less than 2 lm / W or equal to about 2 lm / W are shown below. Spreitzer, H., et al., Soluble phenyl-substituted PPVs-New materials for highly efficient polymer LEDs, Advanced Materials, 1998. 10 (16 ): p. 1340- +, Hsiao, CC, et al., High-efficiency polymer light-emitting diodes based on poly 2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene with plasma-polymerized CHF3 -modified indium tin oxide as an anode "High efficiency polymer light-emitting diode based on poly 2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene and having plasma polymerized CHF3 modified indium tin oxide as anode '', Applied Physics Letters, 2006. 88 (3), Wu, XF, et al., High-quality poly 2-methoxy-5- (2'-ethylhexyloxy) -p-phenylenevinylene synthesized by a solid-liquid two-phase reaction: Characterization and electroluminescence properties High quality poly 2-methoxy-5- (2'-ethylhexyloxy) -p-phenylene vinylene: characterization and electroluminescence properties ", Journal of Polymer Science Part a-Polymer Chemistry, 2004. 42 (12 ): p. 3049-3054, and Malliaras, GG, et al., Electrical characteristics and
efficiency of single-layer organic light-emitting diodes, Physical Review B, 1998. 58 (20): p. 13411-13414. This high performance OLED uses a metal (typically Ca) for the cathode that has a low work function and is therefore very reactive, but the MEH-PPV in the active material disclosed herein. It is noteworthy that LEC devices including include a similar or better power conversion efficiency while using a stable Al cathode.

Santos, G., et al., Opto-electrical properties of single layer flexible electroluminescence device with ruthenium complex, Journal of Non-Crystalline Solids, 2008. 354 (19-25): p. 2571-2574 discloses the first flexible SM LEC, but with a very limited brightness level of 1 cd / m ² and very low power of 0.003 lm / W Efficiency.

  Accordingly, there is a need for improved or alternative light emitting devices, particularly those devices that have a long operational life and / or exhibit increased versatility with respect to their application.

SUMMARY A general object of the present disclosure is to provide a light emitting device that mitigates or eliminates at least some of the disadvantages associated with conventional devices. Individual objectives include providing operating schemes that allow lifetimes of light emitting devices, systems, and / or longer devices.

  The invention is defined by the appended independent claims, and embodiments are set forth in the accompanying dependent claims, the following description and the drawings.

According to the first aspect, there is provided a light emitting device having a first electrode, a second electrode, and a luminescent active material that contacts and separates the first and second electrodes. The active material includes a combination of a conjugated polymer and an electrolyte, and the electrolyte includes ions, enabling electrochemical doping of the conjugated polymer. The ratio of ions to conjugated polymer is selected to allow the formation of (i), (ii):
(I) doped regions at each electrode interface, which allow injection and transport of electronic charge carriers into and through the doped regions, respectively, at zero or low overvoltage, and (ii) doped regions An effective undoped region that separates the injected electronic charge carriers can be recombined by excitation of the conjugated polymer, and the polymer can be de-excited by emission. The ratio of ions to conjugated polymer is low enough so that the undoped region remains effectively undoped and does not contain the ions, and substantially all ions in the active material are confined to the doped region.

  Specific individual material combinations, shapes and temperatures, ion to conjugated polymer ratios (typically mass ratios) can be determined by routine experimentation, such as those described herein. If the access of ions is depleted before the doping fronts (which begin to grow from their respective electrodes) meet, the undoped region will remain undoped.

  The present disclosure is based on the understanding that the factors that limit the operating lifetime of light emitting devices are side reactions that occur in the active material. Therefore, by limiting the amount of ions and other electrolyte components available in the active material, the occurrence and effects of such side reactions can be reduced, thereby improving the operational lifetime of the light emitting device.

  Compared to the prior art, a mixture of hydrophobic conjugated polymer and hydrophilic electrolyte is used, thus producing an active material mixture that is prone to phase separation, yet a similar or better operating life can be achieved. Thus, because of the long operating lifetime in LEC, a single phase active material is possible, although not a requirement, and common hydrophilic electrolytes (essentially all electrolytes except ionic liquids) generally function. Will. This clearly extends the number of electrolytes that can be used considerably.

  Accordingly, the conjugated polymer may be hydrophobic and the electrolyte may be hydrophilic, or the conjugated polymer may be hydrophilic and the electrolyte may be hydrophobic. Thus, the two components will produce a two-phase or multiphase mixture.

The conjugated polymer and electrolyte may form a phase separation mixture, the components of which are separated on a scale in the range of 1 nm to 1 mm The component is on a scale in the range of about 50 nm to about 100 μm, or about 400 nm to about 10 μm May be separated.

  Alternatively, the combination may be a single phase combination.

  The above inventive concept may be combined with a single phase device, ie a device comprising a hydrophilic conjugated polymer and a hydrophilic electrolyte, or a hydrophobic conjugated polymer and a hydrophobic electrolyte. In particular, the selection of materials for the substrate, electrode, conjugated polymer, and electrolyte are those described herein. The concentration of the constituent material in the electrolyte and the driving method are also as described in this specification.

  The ratio of the ions to the conjugated polymer will be selected to provide an undoped region width that effectively eliminates deleterious interactions between the excited conjugated polymer and doped region dopants and ions.

  In embodiments where the electrodes at least partially overlap one another, the ratio of the ions to the conjugated polymer is such that the width of the effectively undoped region is about 10 nm to 200 nm, or about 10-100 nm or about 10-50 nm or It will be selected to be about 20 nm.

In such embodiments, the ratio of the mass of the salt that provides the ion to the mass of the conjugated polymer is about 0.01-3 times z, or about 0.1-3 times, calculated according to the following formula: Or about 0.5-2 times or about 0.5-1 times:

Where x _doping is the doping concentration in the doped region, d _tot is the total distance between the electrodes, d _pn is the width of the undoped region (in the direction between the electrodes), and M _salt is the molar mass of the salt , M _CPru is the molar mass of the repeating unit of the conjugated polymer. All parameters in the formula can be determined or measured by routine experimentation, such as those described herein, with the exception of _dpn . Thus, as shown in the above equation, one particular z value is associated with one particular d _pn (although it is selected).

  The ratio of the ion mass to the conjugated polymer mass may be about 0.005-0.10, or about 0.01-0.06.

  In other embodiments, the electrodes may be substantially coplanar and the ratio of the ions to the conjugated polymer is such that the width of the effectively undoped region is about 10 nm to 70 μm, or about 100 nm to It is selected to be 70 μm, or about 1 μm to 70 μm, or about 10 μm to 70 μm, or about 10 μm to 20 μm.

In either case, the ratio of the ions to the conjugated polymer is at least 100 hours of continuous operation for at least 20 hours, at least 40 hours of continuous operation, at least 60 hours of continuous operation, at least 80 hours of continuous operation. Gives brightness over 100 cd / m ² in continuous operation for hours, continuous operation for at least 150 hours, or continuous operation for at least 200 hours, or continuous operation for at least one month, or ²⁰ cd / m for at least four months maintaining the brightness of greater than ^2, it will be selected to maintain at least 4 days to maintain a luminance of more than 400 cd / ^{m 2,} or at least brightness in excess of 24 hours 1000 cd / ^{m 2.}

  The conjugated polymer comprises poly (paraphenylene vinylene (PPV), polyfluorenylene (PF), poly (1,4-phenylene) (PP), polythiophene (PT), and neutral and ionic derivatives thereof. Will be more selected.

  In particular, the conjugated polymer will be poly [2-methoxy-5- (2-ethyl-hexyloxy) -1,4-phenylene vinylene].

  The conjugated polymer will comprise a phenyl substituted PPV copolymer, such as Super Yellow.

  The electrolyte may include a gel electrolyte.

  Alternatively or as a complement, the electrolyte may comprise a substantially solid electrolyte.

  Alternatively or as a complement, the electrolyte may comprise a substantially liquid electrolyte.

  The device may further include a spacer provided to maintain a predetermined distance between the electrodes. When using a liquid or semi-solid (gel) electrolyte, depending on the design of the device, spacers may be used to maintain the electrodes at a desired distance from each other to avoid shorting the device.

  The electrolyte may contain a salt.

The salt comprises at least one metal comprising a cation, such as Li, Na, K, Rb, Mg, or Ag, and a molecular anion, such as CF ₃ SO ₃ , ClO ₄ , or (CF ₃ SO ₂ ) ₂ N. It may contain salt.

  The electrolyte may include at least one ionic liquid.

The electrolyte in the active material may contain an ion soluble material. The concentration of the ion-soluble substance is sufficiently high to allow ion dissociation and is continuous for at least 20 hours, continuously for at least 40 hours, continuously for at least 60 hours, and continuously for at least 80 hours. In operation, at least 100 hours of continuous operation, at least 150 hours of continuous operation, or at least 200 hours of continuous operation, or at least one month of continuous operation, giving a brightness greater than 100 cd / m ² , or at least 4 either maintain the brightness of greater than monthly 20 cd / ^{m 2,} it will be at least 4 days to maintain a luminance of more than 400 cd / ^{m 2,} or sufficiently low to maintain at least a luminance of greater than 24 hours 1000 cd / ^{m 2.}

  For specific individual material combinations, shapes, and temperatures, the concentration of the salt and ion-soluble substance can be determined by routine experimentation, such as those described herein.

  In certain embodiments, the mass ratio of the ionic soluble material to the conjugated polymer is about 0.01-0.25, about 0.01-0.20, about 0.01-0.17, about 0. .05-0.25, about 0.05-0.20, about 0.05-0.17, about 0.08-0.25, about 0.08-0.20, or about 0.085-0. 17 would be.

  The ion soluble material may comprise at least one polymeric material.

  The polymeric material will be selected from the group consisting of poly (ethylene oxide), poly (propylene oxide), methoxyethoxy-ethoxy substituted polyphosphazan, and polyether-based polyurethane, or combinations thereof.

  The ionic soluble material may include at least one non-polymeric ionic soluble material, such as a crown ether.

  The active material may comprise a surfactant or a polymeric non-ionic soluble material, such as polystyrene.

In one particular embodiment, the electrolyte may comprise KCF ₃ SO ₃ dissolved in poly (ethylene oxide).

  The device will be formed on a substrate.

  The substrate may be effectively non-flexible, such as glass or glass-like material.

  The substrate may be effectively flexible. By “effectively flexible” is meant that the substrate is flexible enough to allow visible bending without breaking.

  The substrate may include a polymeric material such as poly (ethylene terephthalate), poly (ethylene naphthalate), poly (imide), poly (carbonate), or combinations or derivatives thereof.

  The substrate may include a metal foil, such as steel, Ti, Al, Inconel alloy, or Kovar.

  The substrate may include paper or paper-like material.

  One or both of the electrodes may be directly or indirectly deposited on the substrate.

  One or both of the first and second electrodes may be conductive and transparent or translucent.

  Specifically, the electrode may include a translucent oxide, such as indium tin oxide, or a translucent metal thin film, such as Au, Ag, Pt, or Al.

  Alternatively or as a complement, one or both of the first and second electrodes are coated with a thin film of a conductive polymer, such as poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonate).

  One or both of the first and second electrodes may include a metal. The metal will include a stable metal, such as Al, Ag or Au.

  According to a second aspect, there is provided a method for generating light comprising a light emitting device as described above and a power source connected to the first and second electrodes. The power source may be any means suitable for generating electrical power that can be used with the device, such as a battery or converted mains voltage.

  The power source may be provided to provide a preliminary bias for the light emitting device.

  Such a pre-bias can provide a “cleaner” cathode interface and a more central pn junction; the former is attractive because it inhibits the formation of overvoltages at the cathode interface. The result will be a longer operating life and higher power conversion efficiency of the device. The latter is fascinating because it inhibits quenching of light emission by the metal electrode. The result will therefore be higher power conversion efficiency.

  The power supply is provided to provide a pre-bias at a voltage and / or current and duration sufficient to form an effective pn junction.

  As a non-limiting example, a pn junction will be effective when the emission zone is at least 10 nm away from the electrode interface and when the major portion of the applied overvoltage drops beyond the emission zone.

  For example, the pre-bias is less than 1 hour, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 1 minute, less than 30 seconds, less than 15 seconds, less than 5 seconds or less than 1 second. Will be given for a period of time.

  The pre-bias will only be provided when the light emitting device is in a substantially initial or relaxed state.

  The power source may be provided to provide a rated drive voltage and a preliminary bias voltage higher than the rated drive voltage. A typical rated drive voltage would be about 2-4V, for example 2V, 3V or 4V.

  For example, the preliminary bias voltage is about 10% -1000% higher than the rated driving voltage, about 10% -500% higher than the rated driving voltage, about 10% -100% higher than the rated driving voltage, about 30% higher than the rated driving voltage. % -100% higher, or about 30-50% higher than the rated drive voltage.

  The power supply may be provided to provide a rated drive current and a pre-bias drive current higher than the rated drive current.

A typical rated drive current density would be about 100 A / m ² .

  For example, the preliminary bias current is about 2-100 times the rated drive current, about 2-50 times the rated drive current, about 2-20 times the rated drive current, or about 5-20 times the rated drive current. Let's go.

  The power source will be provided to drive the light emitting device at a substantially constant current. Since constant current drive circuits are well known, this will constitute a preferred drive scheme.

  The power source may be provided so as to be always connected to the light emitting device.

  According to a third aspect, there is provided the use of a device or system for generating light as described above.

  According to a fourth aspect, there is provided a method of operating the above device comprising pre-biasing the light emitting device.

  The pre-bias will be applied at a voltage and duration sufficient to form an effective pn junction.

  For example, the pre-bias is less than 1 hour, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 1 minute, less than 30 seconds, less than 15 seconds, less than 5 seconds or less than 1 second Will be given during.

  The pre-bias will be provided when the light emitting device is in a substantially initial or relaxed state.

  A pre-bias voltage higher than the rated drive voltage of the light emitting device will be provided.

  Alternatively, or as a complement, a pre-bias current higher than the rated drive current of the light emitting device may be provided.

  The light emitting device will be driven at a substantially constant current.

  The pre-bias may be provided in connection with the use or testing of components that form part of it.

For a more complete understanding, reference is now made to the following description, taken in conjunction with the accompanying drawings.
1, 1: 0.085: 0.03 in ratio containing the active material in the ITO / PEDOT / shows the long-term operation of the _{{MEH-PPV:: PEO KCF} 3 SO 3} / Al sandwich cell. The device was operated in T = 295K and constant current mode. An initial “pre-bias” current, I _pre-bias = 0.005 was applied for t = 0.5 hours, followed by a long-term uninterrupted operation at I = 0.001A. The inset shows the conformability of a similar device placed on a flexible PET substrate during operation. FIG. 2 shows poly [2-methoxy-5- (2-ethyl-hexyloxy) -1,4-phenylene vinylene] (MEH-PPV), polyethylene oxide (PEO), KCF ₃ SO ₃ and “super yellow”. The chemical structure is shown. 3 is a schematic diagram of the device structure, FIG. 2a is a planar surface cell configuration and FIG. 2b is a vertical sandwich cell configuration. FIG. 4 is a photograph of a planar Au / MEH-PPV + PEO + KCF ₃ SO ₃ / Au LEC with a 1 mm interelectrode gap during operation at V = 5 V and T = 360 K. MEH-PPV: PEO: ratio of _KCF 3 SO ₃ is contained in the title pictures of each set. The positive and negative electrodes are clarified in Photo I, and the doped MEH-PPV corresponds to the dark region that proceeds from the electrode interface. Figure 5 shows a current versus time for the planar _{Au / MEH-PPV + PEO +} KCF 3 SO 3 / Au LEC having in operation at V = 5V and T = 360K, the inter-electrode gap of 1 mm. MEH-PPV: PEO: ratio of _KCF 3 SO ₃ is included in the inset. FIG. 6 schematically illustrates the non-bias initial LEC (FIG. 5a), doping (FIGS. B and c), and light emission (FIG. 5d) processes in the LEC device. Initial doping formation and evolution is stopped by ion depletion (FIG. 5d), so that an appropriately sized undoped pn junction can be designed with a width corresponding to twice the exciton diffusion length ( FIG. 5d). The electric double layer at the charge injection interface is omitted for clarity. 7, as specified by the inset above, different _KCF of the active material 3 SO ₃ ITO having a salt concentration / {MEH-PPV: PEO: KCF 3 SO 3 KCF 3 SO 3} / the Al sandwich cells Indicates a temporary occurrence of brightness. The inset below shows data for a device that does not contain salt in the active material. All devices were driven at V = 3V and T = 360K. FIG. 8 shows the temporal generation of the brightness of an ITO / {MEH-PPV: PEO: KCF ₃ SO ₃ } / Al sandwich cell with different PEO concentrations in the active material, as specified in the inset above. . The device was driven at V = 3V and T = 360K. FIG. 9 shows a planar Au / {MEH-PPV + PEO + KCF ₃ SO ₃ with a 1 mm interelectrode gap during operation at T = 360K and V = 5V (upper panel) and V = 15V (lower panel), respectively. } / Au surface cell propagation and subsequent emission in a Au surface cell. The applied voltage time is shown at the bottom of each photo. FIG. 10 shows for a planar Au / {MEH-PPV + PEO + KCF ₃ SO ₃ } / Au surface cell with a 1 mm interelectrode gap operating at various applied voltages as a function of time (at the time when the pn junction occurs). The average positions of the p-type and n-type doping fronts are shown respectively. FIG. 11 shows the anode (left) and cathode (right) of a planar Au / {MEH-PPV + PEO + KCF ₃ SO ₃ } / Au surface cell with a 1 cm interelectrode gap after 12 hours of operation at V = 30 V and T = 360 K. It is an optical microscope image of an interface. The white line just to the left of the right Au electrode appears to be the product of a cathode electrochemical side reaction. FIG. 12 shows cyclic voltammetry data recorded using working electrodes (WE) of Au (top graph) and Au (bottom graph) coated with a thin film of MEH-PPV. The electrolyte solution was respectively, TBAPF ₆ of 0.1M entered _CH 3 CN (left graph) and 0.1M of _KCF 3 _SO 3 + 2M of the PEO containing a _CH 3 CN (right graph). A silver wire was used as a pseudo reference electrode and calibrated against the Fc / Fc ⁺ reference redox pair at the end of each measurement. The counter electrode was Pt, and the scan speed was 25 mV / s. FIG. 13 is a schematic electron-energy level diagram for an LEC having a reduced level of {KCF ₃ SO ₃ + PEO} electrolyte located within the band gap of the (MEH-PPV) conjugated polymer (CP). (B) during “initial stage” operation when balancing p-type doping of CP at the anode with electrochemical side reactions of electrolyte at the cathode, and (c) subsequent p-type doping to n-type doping. Response of electrons and ions during "late stage" operation when balancing with. Larger circles indicate ions, smaller open and solid circles indicate holes and electrons, respectively, and arrows indicate electron charge injection resulting in electrochemical doping. For clarity, the electrical double layer at the interface is omitted. FIG. 14 shows the temporal generation of luminance of a sandwich cell containing an Al cathode and a {MEH-PPV: PEO: KCF ₃ SO ₃ } active material having a mass ratio of 1: 0.085: 0.03. Long-term operation was performed at V = 3V. Details about each anode structure and initial measurement protocol are specified in the inset above. The bottom inset shows power efficiency as a function of time. 15, 1: 0.085: 0.03 of active material weight ratio with ITO / PEDOT / {MEH-PPV : PEO: KCF 3 SO 3} / Al luminance sandwich cell (left) and the voltage (right) Indicates a temporary occurrence. The device was operated in T = 295K and constant current mode. An initial “pre-bias” current, I _pre-bias = 0.005A, was applied for t = 0.5 hours and then operated for a long time at I = 0.001A. FIG. 16 is a photograph of an ITO / {MEH-PPV: PEO: KCF ₃ SO ₃ } / Al sandwich cell with an active material mass ratio of 1: 0.085: 0.03 provided on a flexible PET substrate. is there. A photograph of the bent device was taken during operation at T = 295K and I = 0.005A. FIG. 17 shows the temporal generation of brightness of ITO / PEDOT / {Super Yellow: PEO: KCF ₃ SO ₃ } / Al sandwich cell with an active material mass ratio of 1: 0.085: 0.03. The device was operated in T = 295K and constant current mode. An initial “pre-bias” current, I _pre-bias = 0.01 A, was applied for t = 0.4 hours and then operated for a long time at I = 0.001 A. FIG. 18 is a photograph of an ITO / {super yellow: PEO: KCF ₃ SO ₃ } / Al sandwich cell with an active material mass ratio of 1: 0.085: 0.03 provided on a flexible PET substrate. . A picture of the bent device was taken during operation at T = 295K.

DESCRIPTION OF EMBODIMENTS In the following disclosure, it is shown that a CP-based LEC (hereinafter LEC) can be designed and manufactured with a record long-term operating life of more than one month, with uninterrupted operation with fairly efficient light emission. Will. This method is based on a combination of careful adjustment of the active material composition and an appropriate operating protocol. These two approaches have been shown to allow the design of doping structures similar to that of SM-OLEDs while at the same time minimizing chemical and electrochemical side reactions that limit lifetime. It also demonstrates the first functional flexible LEC with similar remarkable device performance.

Next, general purpose devices and methods that provide significant improvements in the operating life and power conversion efficiency of light emitting electrochemical cells (LECs) are presented. Specifically, by using a deliberately low concentration of hydrophilic electrolyte (here {PEO + KCF ₃ SO ₃ }) blended with a hydrophobic conjugated polymer (here MEH-PPV or Super Yellow) and distinguished By using a suitable operating protocol whose features are high pre-bias during initial operation, significant brightness of> 100 cd / m ² and relatively high power conversion efficiency (2 lm / W for MEH-PPV, 6 lm / W for super yellow) An operating life of about 1000 hours can be demonstrated with W). The temporary generation of brightness and voltage for such a durable LEC with MEH-PPV as the conjugated polymer is shown in FIG. In addition, the first functional flexible LEC with similar promising device performance is disclosed, and such a conforming device in operation is shown in the inset.

  The origin for improved device performance over previous LEC devices is the effective inhibition of unwanted side reactions. The following will be explained rationally.

(I) why optimization of the electrolyte content in the active material eliminates / minimizes chemical side reactions in the light emitting region of the device; and (ii) why electricity at the electrode interface is determined by a suitable operating protocol. Will chemical side reactions be removed / minimized? First, the achievement (i) of the former will be described in detail.

The effect of ion concentration on the device performance of the planar LEC in the “surface cell” configuration was investigated (see FIG. 3a for a schematic diagram of the device configuration). The device structure is a conjugated polymer poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene disposed above or below two Au electrodes 11 and 12 with an interelectrode gap of 1 mm. From the active material mixture of vinylene] (MEH-PPV, see FIG. 2a), ion solvating and ion transporting polymer poly (ethylene oxide) (PEO, see FIG. 2b) and the salt KCF ₃ SO ₃ (see FIG. 2c). The electrode / active material assembly is disposed on the substrate 10. See Appendix 1 for experimental details on surface cell preparation and operation.

  FIG. 4 shows photographs recorded during operation of four representative planar surface cell devices with gradually decreasing salt concentrations (from top to bottom). The device is operated in the dark room under UV light (which excites the photoluminescence PL of MEH-PPV), so that the doped MEH-PPV in the gap as a dark region (due to doping quenching PL) Can be distinguished. In Photo I, positive electrode 20 is marked with + and negative electrode 21 is marked with-. All devices show both p-type doping formation 23 on the positive electrode and n-type doping formation 24 on the negative electrode (see Photos III and IV). The continuous emissive pn junction 25 is formed only in the top two “ion rich” devices (photo VI in FIGS. 4a and 4b), while the most “ion poor” device has two doping fronts. No complete pn junction formation is shown because it leads to a complete stop at a considerable distance from each other (note that a schematic diagram illustrating the p-type and n-type doping processes in LEC is shown in FIG. Shown).

  FIG. 5 shows a graph of current versus time recorded in parallel with the photograph of FIG. Each graph shows the average of data from 6-10 devices. A significant increase in current with time is observed only in the two ion-rich devices, indicating luminescent pn junction formation.

From the initial appearance of doping until the time of pn junction formation in two ion-rich devices and until the movement of the doping front in two ion-poor devices stops, the current is integrated and this charge is integrated into the doped region. By dividing by the observed volume (determined from the thickness measurements performed by FIG. 4 and atomic force microscope), we determined that the dopant concentration; x _p ˜0.09 ± 0.02 dopant / MEH-PPV It has been found that the doping concentration in the p-type and n-type doped regions is essentially the same, regardless of the repeat unit and x _n ~ 0013 ± 0.03 dopant / MEH-PPV repeat unit. This observation is consistent with the same current and therefore effective device resistance at the time of pn junction formation for the two ion-rich devices (FIG. 5). Ion poor devices contain significant undoped regions with low conductivity, so the effective device resistance is, without exception, quite high.

  The conclusions with these observations are that the doping front is either (i) until they meet to form a luminescent pn junction (see FIGS. 4a and 4b) or (ii) all ions in the active material are It is consumed during electrochemical doping, at which point it propagates at an essentially constant doping concentration until the forward of the doping front stops (observed in FIGS. 4c and 4d) without junction formation. .

This new knowledge is based on the more common and practical “sandwich cell” LEC (herein, as shown schematically in FIG. 3b, the transparent indium tin oxide ITO anode on the glass substrate 10). Provides guidance for the proper design of the doping structure in the active material 13 (including a thin film of active material 13 with a total thickness of d _tot ˜150 nm sandwiched between 11 ′ and the Al cathode 12 ′). The proposed doping design scenario is illustrated in FIG. The concept is that efficient electron charge injection and transport depends on the presence of a well-defined doped region adjacent to the electrodes (cathode 30 and anode 31 in FIG. 6), while efficient injection of injected holes and electrons. Emissive recombination benefits from the presence of an undoped _pn junction region 37 having a d _pn width on the order of 20 nm. The latter size means that recombination of holes and electrons occurs in the undoped pn junction region, the effective diffusion distance of excitons (bonded electron-hole pairs) is about 10 nm, and doping Are induced by effectively quenching the fluorescence of CP. Furthermore, by confining all cations 33 and anions 34 in the active material 32 as counter ion dopants in the well-doped region, on the one hand between excitons generated in the pn junction region and on the other hand in the doped region. Interactions between located ions and / or dopants are minimized, which may be advantageous for operating lifetime.

  The proposed scenario during turn-on of such an optimized LEC is illustrated in FIG. The p-type and n-type doping formation and advancement (36 and 35, respectively) occurs at a constant doping concentration until ion depletion begins and the designed pn junction 37 is formed (see FIG. 6d). See FIGS. 6b and 6c). Such a suitable doping structure allows excitons 38 formed in the pn junction region and uncompensated ions and / or far away dopants in the doped region, as illustrated in FIG. 6d. Can be expected to minimize the interaction between In other words, the width of the pn junction is designed to minimize leakage of the diffusing exciton into the doped region without compromising the efficiency of electron injection and transport. Furthermore, such minimization of salt concentration can effectively reduce the interaction between excitons and ions / dopants, reduce unwanted side reactions in the pn junction region, and concomitantly improve operating lifetime. It will be possible.

The “ideal” ratio (z _ideal ) between the mass of salt and the mass of CP in the active material that enables this desirable doping structure is given by the following general formula (see Appendix 2 for derivation) ) Can be calculated by:

Where x _doping is the doping concentration in the doped region, d _tot is the total length of the active material (equal to the distance between the electrodes), d _pn is the length of the undoped region (in the direction between the electrodes), and M _salt Is the molar mass of the salt, and M _CPru is the molar mass of the repeating unit of the conjugated polymer.

The ideal z value that allows the formation of the desired doping structure with d _pn = 20 nm by filling in the relevant values in equation (1) has d _tot ˜150 nm and is {MEH−PPV + PEO + KCF ₃ SO ₃ } It was found that z = z _ideal = 0.03 for sandwich cells with active material.

FIG. 7 shows a sandwich cell LEC in which the mass ratio of KCF ₃ SO ₃ salt to MEH-PPV in the active material is in the range of z = 0.25 to z = 0.03 as specified in the inset above. Shows the brightness as a function of time (details on the preparation of sandwich cell devices are contained in Example 1). A device with z = 0 was also tested under the same conditions, but no luminescence was detected (see inset below). This is as expected considering the large barrier against electron injection from the Al cathode into the undoped MEH-PPV. The device was driven at V = 3V and T = 360K: use of high temperature (which has been found to reduce operating lifetime by a factor of about 2) sifts a significant number of devices within a reasonable time frame. (All presented data is the average recorded for at least two initial devices). Both the operating lifetime (defined as the time the luminance falls below 100 cd / m ² ) and power efficiency (˜0.2 lm / W; data not shown) are relatively independent of salt concentration, Although a functional doping structure can be achieved at low z = 0.03, the main cause behind the limited operating lifetime of LEC is not simply due to side reactions originating from excess salt More specifically, the main lifetime limiting reaction is not directly attributable to the interaction between excitons and uncompensated ions and / or dopants.

However, LEC active materials typically contain a third ion solvating and ion transporting component (here PEO) in addition to CP and salt, where the effect of PEO concentration on LEC performance is then Attention has shifted to. The mass ratio between the KCF ₃ SO ₃ salt and MEH-PPV is kept constant at a low value of z = 0.03, and the mass ratio between PEO and MEH-PPV is y = 1.35 (used in the device). It is chosen to change from y (typical value) to y = 0.058.

  FIG. 8 shows that the concentration of PEO has a significant impact on device performance. It has been found that the operating lifetime increases monotonically and dramatically as the amount of PEO is decreased, from about 2 hours at y = 1.35 to about 65 hours at y = 0.085. Compared to about 0.2 lm / W for devices with high PEO content of y = 1.35, devices with low PEO content (y ≦ 0.34) are greater than about 0.5-0.7 lm / W Although showing power efficiency, power efficiency is still quite small (data not shown).

  Furthermore, Wagberg, T., et al., On the limited operational lifetime of light-emitting electrochemical cells, Advanced Materials, 2008. 20 (9): p. 1744- As described in 1746, an open planar surface cell structure with the same active material components was utilized with the intention of identifying chemical traces and spatial location of side reactions that limit lifetime in LEC. . By optically inspecting the subsequent device, the vinyl groups and fluorescein capabilities of the MEH-PPV polymer are severely and irreversibly impaired at the end of LEC operation, but at or near the pn junction. Only in a limited spatial region.

Therefore, considering the results shown in FIGS. 7 and 8, the main lifetime limiting reaction is due to the spatial coexistence and chemical interaction of excitons on the MEH-PPV chain with the {PEO + KCF ₃ SO ₃ } electrolyte. It seems very relevant to be involved. Furthermore, this irreversible chemical reaction is initiated by electron transfer from the LUMO of the photoexcited MEH-PPV to the unoccupied energy level of the {PEO + KCF ₃ SO ₃ } electrolyte, and the subsequent chemical reaction is MEH − It has been proposed to include chemical attack of the exposed vinyl groups of the PPV polymer. If the electrolyte content in the active material is reduced from a normal high rate (here y = 1.35, z = 0.25) to a much lower rate (y = 0.085, z = 0.03), p The effective reduction of the MEH-PPV exciton interaction with the electrolyte in the -n junction region reasonably explains a significant 30-fold increase in device lifetime, as observed in FIG.

Next, the focus is shifted to the second part, the influence of the operating protocol on the device performance. 9, the two representative planar _{Au / {MEH-PPV + PEO} + KCF 3 SO 3} / Au surface cell device with an electrode gap of 1 mm, a series of photos of the forward and subsequent emission doping front. In the photograph, the positive anode 20 is located on the left and the negative cathode 21 is located on the right. Doped regions 23 and 24 appear as dark regions occurring at the electrode interface (marked with dashed lines). The device shown in the upper panel of the photo is biased with V = 5V, and the device shown in the lower panel of the photo is biased with V = 15V. The presented photos were two photos marked with the same letter and were chosen so that the p-type doping front advanced the same distance in the interelectrode gap.

  It is clear that the start of n-type doping is delayed in both devices compared to the start of p-type doping (as observed in the device of FIG. 4); two pictures in FIG. See b). Here, not the n-type doping 24 but the p-type doping 23 is clearly visible. Furthermore, in the first evidence of n-type doping 24, n already seen in photo c) for devices biased at V = 15V, but only in photo d) for devices biased at V = 5V, n This delay in onset of -type doping is quite noticeable in devices biased at V = 5V. The delay in the onset of n-type doping is directly related to the fact that in devices biased at V = 5V, the luminescent pn junction 25 is formed closer to the negative cathode 21 (see photos e and f). Have a result.

  Two other interesting and consistent observations on all devices investigated (> 40 in total) relate to the shape of the doping front. First, the shape of the p-type front becomes jagged with time and with increasing voltage, which is a direct result of the turn-on process limited by ion transport. Second, although more relevant here, the initial n-type front shows a spike-like appearance that is not present in the initial p-type front. This issue will come back later.

  FIG. 10 shows the average position of the p-type doping front and the n-type doping front (normalized to the time at which the pn junction occurs) as a function of time at various applied voltages. Three general trends are evident: (i) p-type doping onset time is essentially independent of applied voltage; (ii) n-type doping onset is more pronounced at low applied voltage (Iii) The average position of the emissive pn junction (as observed at time = 1.0) is 0.59 mm away from the positive anode in a device with a 1 mm interelectrode gap at V = 20V. From there, V = 5V to 0.76 mm, as the applied voltage is decreased, it shifts towards the negative cathode.

  Compared to the onset of p-type doping, the delay in the onset of n-type doping is significantly increased, and at low temperatures the pn junction is known to shift to the cathode side (data not shown) ) And similar behavior has been observed with decreasing temperature. Since these active materials are well established to exhibit strongly temperature-dependent ionic conductivity, we have an increasing delay in the onset of n-type doping, and the resulting cathode shift of the pn junction, This is attributed to the reduced ionic conductivity.

  A balanced redox should be maintained at the two electrode interface in the LEC during the doping advance (limited Faraday doping at one electrode is compensated by non-Faraday electric double layer formation at the other electrode. Although it is possible in principle, JH Shin, S. Xiao, and L. Edman, Polymer light-emitting electrochemical cells: The formation and effects of doping-induced micro shorts "Short Formation and Effect", Advanced Functional Materials, 2006. 16 (7): p. 949-956, this effect is too small, for example n- in wide gap devices investigated in FIGS. 9 and 10 [10]. The considerable delay in the start of type doping cannot be explained). Therefore, other electrochemical reactions other than n-type doping of CP must occur at the cathode interface, and we have chosen to refer to such reactions generically as “electrochemical side reactions”.

Optical microscopy images provide direct visible evidence for electrochemical side reactions at the cathode interface of the device, showing a significant time difference between the onset of p-type and n-type doping. FIG. 11 shows the anode interface 40 (left) and cathode interface of a planar Au / {MEH-PPV + PEO + KCF ₃ SO ₃ } / Au surface cell with an extremely large interelectrode gap of 1 cm after long-term operation at V = 30V. 41 (right). The anode interface 40 maintains a “clean” appearance after long-term operation, but a bright “degraded layer” 43 appears at the cathode interface between the negative Au electrode and the {MEH-PPV + PEO + KCF ₃ SO ₃ } active material. . It is easiest to find a degraded layer in devices that exhibit slow doping rates, ie devices that operate at low overvoltages and / or low temperatures (if the ionic conductivity of the active material is very low) and with large interelectrode gaps It is interesting to know that.

Insights into the electronic structure of the various components of the LEC, namely the Au electrode, the MEH-PPV polymer, and the {KCF ₃ SO ₃ + PEO} electrolyte are given by cyclic voltammetry (CV). FIG. 12 shows the use of bare Au (top graph) or MEH-PPV thin film coated Au (bottom graph) as the working electrode and CH ₃ CN (left graph) with TBAPF ₆ as the electrolyte solution or CV data recorded using CH ₃ CN (right graph) with {KCF ₃ SO ₃ + PEO} is shown. The upper left graph shows that the bare Au electrode is electrochemically inactive in the voltage range tested (over -2.6V to + 0.8V for the Fc / Fc ⁺ pair), left graph is MEH-PPV is reversibly n- type doped at -2.3V against Fc / Fc ⁺ (reduction), reversibly p- type doped + 0.1 V with respect to Fc / Fc ⁺ It shows that it can be oxidized. Irreversible reduction reaction in both bare Au electrode system (upper right graph) and MEH-PPV coated Au electrode system (lower right graph) when the electrolyte is changed from TBAPF ₆ to {KCF ₃ SO ₃ + PEO} The situation has changed due to the occurrence of Based on these data, the conclusion will be drawn that the {KCF ₃ SO ₃ + PEO} electrolyte is irreversibly reduced at a lower potential than MEH-PPV is reversibly n-doped.

FIG. 13 shows the operating mechanism of the proposed LEC in the form of a schematic electron-energy level. Consistent with the CV data, we show in FIG. 13 (a) that the reduction level of the {KCF ₃ SO ₃ + PEO} electrolyte is lower than the conduction band edge of MEH-PPV (which roughly corresponds to the n-type doping level). The position is included. As shown in FIG. 13 (b), during the “early stage” operation, the electrochemical in the LEC is reduced by p-type doping (oxidation) of MEH-PPV at the anode and reduction of the electrolyte at the cathode. Redox balance is maintained. The latter reaction corresponds to an electrochemical side reaction, which is due to the lack of n-type doping during early stage operation (see FIGS. 9 and 10) and at the interface between the negative Au electrode and the active material. Appear in the form of a deteriorated layer (see FIG. 11). During “late phase” operation, p-type doping at the anode is instead balanced by n-type doping at the cathode, and it is during this process that n-type doping appears in FIGS. 9 and 10. .

  A problem worthy of note at this stage is the transition between electrochemical side reactions and n-type doping at the Au cathode, which is why higher applied voltage and / or increased ionic conductivity of the active material. It will happen sooner. While side reactions are thermodynamically preferred cathode reactions (which are supported by CV data), it has been proposed that n-type doping is a kinetically preferred cathode reaction at the Au cathode interface. This is because when using very small overvoltages with small drive voltages, i.e. all overvoltages fall over the undoped region of low ion conductivity, the n-type doping reaction is simply not energetically accessible, so thermodynamically The result is a favorable side reaction wins. The higher the drive voltage or the ionic conductivity of the undoped region (which separates the p-type and n-type regions) increases (because of its increased ionic conductivity or during later stages of the doping process This situation will change. This is because there is sufficient overvoltage available at the cathode interface to allow both side reactions and n-type doping. In such a scenario, n-type doping, which is a kinetically favorable reaction, dominates. Furthermore, during late phase operation, if the effective cathode interface is located at the n-type doping front rather than the Au cathode, the data obtained indicate that n-type doping is the dominant process.

  Two directly visible conclusions of the electrochemical side reaction are that the onset of n-type doping is delayed and that the pn junction shifts towards the cathode. Also, electrochemical side reactions produce reaction residues on the surface of the Au cathode (visualized in FIG. 11), which will then at least partially interfere with the initial n-type doping. I can expect that. The presence of a partial passivation layer on the Au cathode surface rather than on the Au anode surface with side reactions indicates that the initial n-type doping front has a spike-like appearance that is not present in the initial p-type front. This is consistent with the observation (see FIG. 9). The presence of an insulative degradation layer between the negative Au electrode and the active material has implications for voltage distribution in an LED including a light-emitting pn junction that is turned on. This is because it is reasonable to think that it causes a significant part of the overvoltage for a shift from, for example, a pn junction to a degraded layer.

  Therefore, to minimize cathode side reactions and improve device performance, it is reasonable to apply a large potential ("pre-bias") during the initial doping formation process. Thereafter, when a pn junction occurs, it is appropriate to reduce the applied potential to enable long-term operation. FIG. 14 illustrates the effect of this operating protocol on sandwich cell performance.

  The sandwich cell device is the same as shown in FIGS. 7 and 8, with the notable difference that the test was performed at room temperature instead of high temperature of T = 360K. The decrease in T resulted in an improvement in operating life up to about twice. In addition, using established techniques to coat the surface of the ITO anode with a thin planarization layer of the conductive polymer PEDOT, we investigated whether the roughness of the ITO surface affects device performance; We have found that this additional layer provides only a slight improvement. The cumulative effect on device performance due to the decrease in T and the introduction of the PEDOT layer at the anode interface is shown in FIG. 14 (compare the open square with the star).

During the initial doping process, the sandwich cell device is “pre-biased” with V _pre-bias = 4V, and when significant emission is achieved and doping is complete (from t to 0.5 hours), the voltage is set to V = It drops to 3V. The result of using a large reserve bias (solid circle in FIG. 14) is clearly encouraging. The operating life increases from about 125 hours to about 175 hours, and the power efficiency increases significantly from a high value of about 0.5-0.6 lm / W to about 1.9 lm / W.

It is expected that a high pre-bias during device turn-on will result in an increased amount of n-type doping at the expense of cathode side reactions involving {PEO + KCF ₃ SO ₃ } electrolyte. The necessary and desirable conclusion during long-term operation is a “cleaner” cathode interface and a more central pn junction; the former is attractive because it inhibits the generation of overvoltage at the cathode interface, while The latter, Lee, KW, et al., Photophysical properties of tris (bipyridyl) ruthenium (II) thin films and devices, “Photophysical properties of tris (bipyridyl) ruthenium (II) thin films and devices”, Physical Chemistry Chemical Physics, 2003 5 (12): Exciton annihilation by nearby metal electrodes, as described in p. 2706-2709, and JH Shin, S. Xiao, and L. Edman, Polymer light-emitting electrochemical cells: The formation and effects of doping-induced micro shorts "Polymer light-emitting electrochemical cells: Formation and effects of doping-induced micro shorts", Advanced Functional Materials, 2006. 16 (7): p. 949-956 and Johansson, T., et al., Light-emitting electrochemical ce lls from oligo (ethylene oxide) -substituted polythiophenes: Evidence for in situ doping -It is desirable to effectively eliminate the literature issues related to the generation of doping induced shorts as described in 3139. The inhibition of these processes is directly related to the increased power conversion efficiency, while the removal of doping shorts and cathode side reactions in particular can be expected to result in an improved operating life. Thus, it seems likely to rationalize the observed improved device performance with high pre-bias that mitigates electrochemical side reactions. In addition, the high pre-bias is attractive from a turn-on time perspective, and we see that a device _pre- biased with V _pre-bias = 4V is> 70 times faster than the same device biased constant at V = 3V. Reaching a luminance of 100 cd / m ² .

Inspired by the strong influence of operating protocols on device performance, we chose to study the effect of bias mode. FIG. 15 shows brightness and brightness as a function of time for sandwich cells operated at a constant current (constant current mode) instead of a constant voltage (constant voltage mode as in FIGS. 7-8 and 14). Indicates voltage. In order to minimize cathode side reactions and speed up turn-on time, we set the initial _pre-bias current to 0.5 hour with a high value of I _pre-bias = 0.005A and immediately after that I = 0. Reduced to 001A. The result is very promising: the initial power efficiency is> 2 lm / W and the operating time reaches a remarkable value of about 1000 hours or> 40 days. It is also noteworthy that the applied voltage during the uninterrupted operation exceeding 1 month at I = 0.001A does not exceed V = 4V.

The improved device performance in FIG. 15 is due to the high initial voltage resulting in V≈6V during the first few seconds of high current operation at I _pre-bias = 0.005A. Furthermore, the high pre-bias reduces undesirable cathode electrochemical side reactions compared to the low initial bias of V = 3-4V applied during constant voltage operation in FIGS. 7, 8 and 14. Will inhibit. Furthermore, due to exciton non-radiative decay and Joule heating (the junction is undoped and is itself the most resistive part of the device), the self-heating effect is quite prevalent in the pn junction region during steady state operation. Wagberg, T., et al., On the limited operational lifetime of light-emitting electrochemical cells, Advanced Materials, 2008. 20 (9) : p. 1744- +, and Zhang, YG and J. Gao, Lifetime study of polymer light-emitting electrochemical cells, Journal of Applied Physics, 2006. 100 (8). As can be seen, the good performance in the constant current mode when compared to the constant voltage mode can be attributed, in part, to good thermal management of the pn junction region.

  Furthermore, the first highly functional LEC device on a flexible ITO coated PET substrate is demonstrated. FIG. 16 shows two photographs, which show the conformability of such a sandwich cell in operation. Device performance (ie, maximum brightness, power conversion efficiency, and operating life) of such flexible LEC devices was provided on a non-flexible glass substrate by accelerated life testing at high applied currents of I = 0.001A. It has been found to be equivalent to the best performance of the device shown above.

Finally, it demonstrates that by using the active material composition optimization and high pre-bias protocol described above, remarkable device performance can be achieved with other active material components. For example, “super yellow” (see FIG. 2 d for chemical structure) was used as the conjugated polymer instead of MEH-PPV. FIG. 17 shows an initial luminance versus time test for a sandwich cell device operated at I _pre-bias = 0.01A for 0.4 hours and immediately thereafter with the current reduced to I = 0.001A. The power conversion efficiency of such a yellow light emitting device can reach 6 lm / W, the initial operating lifetime data is the same for a super yellow device with an appropriate low electrolyte concentration and exposed to an appropriate operating protocol. It can be shown that the operating life equivalent to that of the MEH-PPV-based device optimized can be shown. In FIG. 18, we show a fully flexible Super Yellow LEC device in operation.

In summary, active material composition and operational protocols have been demonstrated to have a significant impact on LEC device performance. Specifically, sandwiched between the stable ITO and Al electrodes red emission LEC having an active material mixture _{{MEH-PPV:: PEO KCF} 3 SO 3} _{is, {PEO: KCF 3 SO 3} } electrolyte By optimizing the concentration and applying a high pre-bias during initial operation, a remarkable operating life of about 1000 hours can be achieved with significant brightness> 100 cd / m ² and high power conversion efficiency of ² lm / W. Two effective pathways for reducing adverse chemical and electrochemical side reactions (these may be used separately or together) have been demonstrated. Furthermore, a very promising flexible LEC was demonstrated.

EXAMPLES The present disclosure is further illustrated by the following specific examples, which should not be construed as limiting the scope and content of the claimed invention in any way.

In the first example, the conjugated polymer poly [2-methoxy-5- (2-ethyl-hexyloxy) -1,4-phenylenevinylene] (MEH-PPV) was used as received. Poly (ethylene oxide) (PEO, M _w = 5 × 10 ⁶ , Aldrich) and the salt KCF ₃ SO ₃ (98%, Alfa Aesar) were dried under vacuum at temperatures (T) of 323 K and 473 K, respectively. The 10 mg / mL concentrated master solution was prepared: MEH-PPV dissolved in chloroform (> 99%, anhydrous, Aldrich), and PEO and dissolved separately in chloro hexanone _{KCF 3 SO 3 (99%,} Merck). By mixing a master solution with 1: 0.085: 0.03 of MEH-PPV: PEO: by the _KCF 3 SO ₃ weight ratio, was prepared a blend solution, the magnetic hotplate, T = 323 K For at least 5 hours. Indium tin oxide (ITO) glass substrate (1.5 × 1.5 cm ² , 20 ± 5 ohms / sq., TFD Inc) was cleaned by continuous sonication in detergent, acetone, and isopropanol solutions. An active material was deposited by spin coating the blend solution at 800 rpm, and a film thickness of about 150 nm was obtained as measured by an atomic force microscope. Thereafter, the active material was dried on a hot plate at T = 333K for at least 5 hours. Al electrodes were deposited by thermal evaporation at p <2 × 10 ⁻⁴ Pa. For some devices, 1.3 wt% in poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonate) (PEDOT-PSS H ₂ O) on ITO at 4000 rpm prior to active material deposition. The dispersion, Sigma Aldrich) was spin coated. All the above device fabrication operations were performed in two interconnected N ₂ encapsulated glove boxes (O ₂ <3 ppm, H ₂ O <0.5 ppm), except for substrate cleaning and PEDOT deposition. Prior to testing, the device was dried in situ in a cryostat for 2 hours at T = 360 K and under high vacuum (p <10 ⁻³ Pa). All measurements were performed under high vacuum (p <10 ⁻³ Pa) in the same optical access cryostat. A computer-controlled power measurement unit (Keithley 2400) was used in combination with a calibration photodiode to evaluate the photoelectric properties of the LEC device.

  In another example, the conjugated polymer “Super Yellow” was used instead of MEH-PPV. Super Yellow is a soluble phenyl substituted PPV copolymer, purchased from Merck and used as received. This was handled in the same manner as the MEH-PPV polymer in the above example.

  In yet another example, a flexible ITO-coated poly (ethylene terephthalate) (PET) substrate (PET60, Visiontek Systems Ltd.) was used in place of the non-flexible ITO glass substrate. These substrates were used as received.

Addendum 1—Experimental Details for Surface Cell Poly [2-methoxy-5- (2-ethyl-hexyloxy) -1,4-phenylenevinylene] (MEH-PPV, Aldrich, M _n = 40000-70000 g / mol) Used as received. Poly (ethylene oxide) (PEO, M _w = 5 × 10 ⁶ , Aldrich) and the salt KCF ₃ SO ₃ (98%, Alfa Aesar) were dried under vacuum at a temperature (T) of 473K. A 10 mg / L master solution of MEH-PPV (> 99%, anhydrous, Aldrich) dissolved in chloroform and PEO and KCF ₃ SO ₃ (99%, Merck) dissolved separately in cyclohexane was prepared. These master _{solutions, MEH-PPV: PEO: KCF} 3 SO 3 = 1: 1.35: mixed with 0.25 weight ratio, then the magnetic hot plate, stirred for at least 5 hours at T = 323 K The blend solution was prepared. Next, a 1.5 × 1.5 cm ² glass substrate was cleaned by sonication in a detergent, acetone and isopropanol solution. A 100 nm thick Au electrode was deposited on these cleaned glass substrates by thermal evaporation at p <2 × 10 ⁻⁴ Pa. The interelectrode gap was provided by an Al shadow mask.

The blend solution was deposited by spin coating at 800 rpm for 60 seconds to obtain an active material film having a thickness of 150 nm. The membrane was then dried on a hot plate at T = 333K for at least 5 hours. Finally, measurements were performed immediately and in situ drying was performed in a cryostat for 2 hours at T = 360 K and under vacuum (p <10 ⁻³ ). All of the device manufacturing procedures described above, except for substrate cleaning, were performed in an Ar-filled glove box (O ₂ <3 ppm, H ₂ O <0.5 ppm). Device characteristics were evaluated in a light access cryostat under vacuum (p <10 ⁻³ ). A computer-controlled power measurement unit (Keithley 2400) was used to measure the current obtained by applying the voltage. Photos of the progress of doping were recorded using a digital camera with a macro lens (Cannon EOS 20D) through the optical window of the cryostat under UV (λ = 365 nm) illumination.

Cyclic voltammetry (CV) measurements were performed using a computer controlled potentiostat / galvanostat (Autolab, PGSTAT302 / FRA2, Eco Chemie) using general purpose electrochemical software (GPES, Eco Chemie). All measurements were performed in an Ar-filled glove box (O ₂ <3 ppm, H ₂ O <0.5 ppm). The electrolyte is either 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF ₆ , ≧ 99.0%, Fluka) in acetonitrile (CH ₃ CN, anhydride, ≧ 99.8%, Aldrich) or acetonitrile. Low molecular weight PEO (Mw calculated as the number of repeating units of PEO per liter of solution) and 0.1 M potassium trifluoromethanesulfonate (KCF ₃ SO ₃ , 98%, Alfa Aesar) in = 400, Polysciences). The working electrode was deposited on a previously cleaned glass substrate by thermal evaporation at p = 2 × 10 ⁻⁴ Pa. MEH-PPV membranes were spin-coated from chloroform solution (10 mg / ml,> 99%, anhydrous, Aldrich) onto Au electrodes at 800 rpm for 60 seconds, then ˜1 hour at T = 323 K on hot plate Dried over. A silver wire was used as a quasi-reference electrode. At the end of each measurement, the silver wire is converted to bis- (η-cyclopentadienyl) iron (II) / bis- (by adding 10 ⁻⁵ mol of ferrocene to the electrolyte and performing a sweep. Calibrated against η-cyclopentadienyl) iron (II) ⁺ ion (ferrocene / ferrocenium ion, Fc / Fc ⁺ ) reference redox couple (ferrocene, ≧ 98%; Fluka). A Pt bar was used as the counter electrode. The reduction / oxidation onset potential corresponding to the intersection of the baseline and half width tangent was determined. All potentials for the Fc / Fc ⁺ reference redox pair were reported.

Appendix 2-Derivation of Formula (1) The effective density of the conjugated polymer (CP) and salt (and other components) in the active material (AM) is

Can be related to their respective mass fractions. Here ρ _AM is the density of the active material.

The densities of CP and CP repeating units (CPru) are the same.

The number density of the components in the active material is

Given by. Where N _A is the Avogadro constant, M _i is the molar mass of component i.

We further mention that in the case of monovalent salts the following is true:

In the ion deficient state, all ions of one type accumulate in one separate doping region, where they electrostatically supplement the dopant (anions supplement holes in the p-type region, Cations compensate for electrons in the n-type region). Furthermore, the doping concentration in the doped region and hence the ion concentration is constant. Therefore, the dopant and ion concentrations in each doped region are:

_Is related to the volume of the doped region (V _i , i = p, n) and the total volume of the active material (V _tot ).

If the cross-sectional area of the active material is constant, the equations for p-type and n-type doping concentration are

Can be rewritten. Here d _tot is the total distance between the electrodes, d _p and d _n is the total distance in each of the inter-electrode direction of p- type and n- type region.

The doping fraction (x _i , i = p, n) in the doped region can now be calculated using the following equation:

Including the above results and solving for the p-type region in particular, we found the following:

Here we solve for the ratio z of the salt mass to the conjugate mass:

We reasoned (J. Fang, et al. Identifying and alleviating electrochemical side-reactions in light-emitting electrochemical cells, Journal of the American Chemical Society, 2008 , 130 (13): p. 4562-4568)) If we estimate the doping concentrations in the two doped regions to be equal,

and

I found out. Here, d _pn is the width of the undoped _pn junction.

Under these special conditions, equation (11) can be rewritten as:

Also disclosed is a method for generating light comprising a light emitting device as described above and a power source connected to the first and second electrodes. The power source may be any means suitable for generating electrical power that can be used with the device, such as a battery or converted mains voltage.

According to a second aspect, there is provided the use of a device or system for generating light as described above.

According to a third aspect, there is provided a method of operating the above device comprising pre-biasing the light emitting device.

以下に、本願出願の当初の請求項の記載を実施の態様として付記する。
［１］ 第１の電極と、第２の電極と、第１および第２の電極に接触してこれらを分離する発光活物質とを有する発光デバイスであって、前記活物質は、
共役ポリマーと電解質との組み合わせを含み、前記電解質はイオンを含み、共役ポリマーの電気化学ドーピングを可能にし、
イオンと共役ポリマーとの比は（ｉ）、（ｉｉ）の形成を可能にするように選択され、
（ｉ）それぞれの電極界面のドープ領域であって、これらはゼロまたは低過電圧で、それぞれ、ドープ領域へのおよびこれを通しての電子電荷キャリアの注入および輸送を可能にする、および
（ｉｉ）ドープ領域を分離する実効的なアンドープ領域であって、注入された電子電荷キャリアは共役ポリマーの励起により再結合可能であり、前記ポリマーは発光により脱励起可能である、
イオンと共役ポリマーとの比は、前記アンドープ領域が実効的にアンドープのままで前記イオンを含まず、前記活物質中の実質的にすべてのイオンが前記ドープ領域に閉じ込められるように十分に低い、発光デバイス。
［２］ 前記共役ポリマーが疎水性で前記電解質が親水性であるか、または前記共役ポリマーが親水性で前記電解質が疎水性である、［１］に記載のデバイス。
［３］ 前記共役ポリマーおよび電解質は相分離した混合物を形成し、その成分は１ｎｍないし１ｍｍの範囲のスケールで分離している、［１］に記載のデバイス。
［４］ 前記成分は約５０ｎｍないし約１００μｍ、または約４００ｎｍないし約１０μｍの範囲のスケールで分離している、［３］に記載のデバイス。
［５］ 前記組み合わせは実質的に単相の組み合わせである、［１］に記載のデバイス。
［６］ 前記イオンと共役ポリマーとの比は、励起した共役ポリマーとドープ領域のドーパントとイオンとの間の有害な相互作用を実効的になくすアンドープ領域の幅を与えるように選択される、［１］ないし［４］のいずれか１に記載のデバイス。
［７］ 前記電極は少なくとも部分的に互いに重なり、前記イオンと共役ポリマーとの比は、前記実効的にアンドープな領域の幅が約１０ｎｍないし２００ｎｍ、または約１０−１００ｎｍまたは約１０−５０ｎｍまたは約２０ｎｍになるように選択される、［６］に記載のデバイス。
［８］ 前記イオンを与える塩の質量と共役ポリマーの質量との比が、下記式に従って計算されるｚの約０．０１−３倍、または約０．１−３倍、または約０．５−２倍または約０．５−１倍に選択される、

（ここで、ｘ _{ｄｏｐｉｎｇ} はドープ領域におけるドーピング濃度であり、ｄ _ｔｏｔ は電極間の全距離であり、ｄ _ｐｎ は（電極間方向の）アンドープ領域の幅であり、Ｍ _ｓａｌｔ は塩のモル質量であり、Ｍ _ＣＰｒｕ は共役ポリマーの繰り返し単位のモル質量である）
［７］のデバイス。
［９］ 前記イオンの質量と前記共役ポリマーの質量との比が約０．００５−０．１０、または約０．０１−０．０６である、［１］ないし［８］のいずれか１のデバイス。
［１０］ 前記電極は実質的に同一平面上にあり、前記イオンと前記共役ポリマーとの比は、前記実効的にアンドープな領域の幅が約１０ｎｍないし７０μｍ、または約１００ｎｍないし７０μｍ、または約１μｍないし７０μｍ、または約１０μｍないし７０μｍ、または約１０μｍないし２０μｍになるように選択される、［１］ないし［６］のいずれか１に記載のデバイス。
［１１］ 前記イオンと前記共役ポリマーとの比は、少なくとも２０時間の連続動作で、少なくとも４０時間の連続動作で、少なくとも６０時間の連続動作で、少なくとも８０時間の連続動作で、少なくとも１００時間の連続動作で、少なくとも１５０時間の連続動作で、または少なくとも２００時間の連続動作で、または少なくとも１か月間の連続動作で１００ｃｄ／ｍ ^２ を超える輝度を与える、または少なくとも４か月間２０ｃｄ／ｍ ^２ を超える輝度を維持する、少なくとも４日間４００ｃｄ／ｍ ^２ を超える輝度を維持する、または少なくとも２４時間１０００ｃｄ／ｍ ^２ を超える輝度を維持するように選択される、［１］ないし［１０］のいずれか１に記載のデバイス。
［１２］ 前記共役ポリマーはポリ（パラフェニレンビニレン（ＰＰＶ）、ポリフルオレニレン（ＰＦ）、ポリ（１，４−フェニレン）（ＰＰ）、ポリチオフェン（ＰＴ）、ならびにこれらの中性およびイオン性の誘導体からなる群より選択される、［１］ないし［１１］のいずれか１に記載のデバイス。
［１３］ 前記共役ポリマーはポリ［２−メトキシ−５−（２−エチル−ヘキシルオキシ）−１，４−フェニレンビニレン］である、［１２］に記載のデバイス。
［１４］ 前記共役ポリマーは、フェニル置換ＰＰＶコポリマー、たとえばスーパーイエローを含む、［１］ないし［１２］のいずれか１に記載のデバイス。
［１５］ 前記電解質はゲル電解質を含む、［１］ないし［１４］のいずれか１に記載のデバイス。
［１６］ 前記電解質は実質的に固体の電解質を含む、［１］ないし［１５］のいずれか１に記載のデバイス。
［１７］ 前記電解質は実質的に液体の電解質を含む、［１］ないし［１６］のいずれか１に記載のデバイス。
［１８］ さらに、電極間に所定の距離を維持するように設けられたスペーサーを有する、［１］ないし［１７］のいずれか１に記載のデバイス。
［１９］ 前記電解質は塩を含む、［１］ないし［１８］のいずれか１に記載のデバイス。
［２０］ 前記塩は少なくとも１つの金属塩を含み、前記塩はカチオン、たとえばＬｉ、Ｎａ、Ｋ、Ｒｂ、Ｍｇ、またはＡｇと、分子アニオン、たとえばＣＦ _３ ＳＯ _３ 、ＣｌＯ _４ 、または（ＣＦ _３ ＳＯ _２ ） _２ Ｎとを含む、［１９］に記載のデバイス。
［２１］ 前記活物質中の電解質はイオン溶解性物質を含む、［１］ないし［２０］のいずれか１に記載のデバイス。
［２２］ 前記イオン溶解性物質の濃度はイオンの解離を可能にするのに十分高く、かつ少なくとも２０時間の連続動作で、少なくとも４０時間の連続動作で、少なくとも６０時間の連続動作で、少なくとも８０時間の連続動作で、少なくとも１００時間の連続動作で、少なくとも１５０時間の連続動作で、または少なくとも２００時間の連続動作で、または少なくとも１か月間の連続動作で１００ｃｄ／ｍ ^２ を超える輝度を与える、または少なくとも４か月間２０ｃｄ／ｍ ^２ を超える輝度を維持する、少なくとも４日間４００ｃｄ／ｍ ^２ を超える輝度を維持する、または少なくとも２４時間１０００ｃｄ／ｍ ^２ を超える輝度を維持するのに十分低い、［２１］に記載のデバイス。
［２３］ 前記イオン溶解性物質と前記共役ポリマーとの質量比は、約０．０１−０．２５、約０．０１−０．２０、約０．０１−０．１７、約０．０５−０．２５、約０．０５−０．２０、約０．０５−０．１７、約０．０８−０．２５、約０．０８−０．２０または約０．０８５−０．１７である、［２１］または［２２］に記載のデバイス。
［２４］ 前記イオン溶解性物質は少なくとも１つのポリマー物質を含む、［２１］ないし［２３］のいずれか１に記載のデバイス。
［２５］ 前記ポリマー物質はポリ（エチレンオキシド）、ポリ（プロピレンオキシド）、メトキシエトキシ−エトキシ置換ポリホスファザン、およびポリエーテル系ポリウレタン、またはこれらの組み合わせからなる群より選択される、［２４］に記載のデバイス。
［２６］ 前記イオン溶解性物質は少なくとも１つの非ポリマーのイオン溶解性物質、たとえばクラウンエーテルを含む、［２１］ないし２３］のいずれか１に記載のデバイス。
［２７］ 前記電解質は少なくとも１つのイオン性液体を含む、［１］ないし［２６］のいずれか１に記載のデバイス。
［２８］ 前記活物質は界面活性剤、またはポリマーの非イオン溶解性物質、たとえばポリスチレンを含む、［１］ないし［２７］のいずれか１に記載のデバイス。
［２９］ 前記電解質はポリ（エチレンオキシド）に溶解したＫＣＦ _３ ＳＯ _３ を含む、［１］ないし［２８］のいずれか１に記載のデバイス。
［３０］ 前記デバイスは基板上に形成されている、［１］ないし［２９］のいずれか１に記載のデバイス。
［３１］ 前記基板は実効的にノンフレキシブルである、［３０］に記載のデバイス。
［３２］ 前記基板はガラスまたはガラス様物質を含む、［３１］に記載のデバイス。
［３３］ 前記基板は実効的にフレキシブルである、［３０］に記載のデバイス。
［３４］ 前記基板はポリマー物質を含む、［３３］に記載のデバイス。
［３５］ 前記ポリマー物質はポリ（エチレンテレフタレート）、ポリ（エチレンナフタレート）、ポリ（イミド）、ポリ（カーボネート）、またはこれらの組み合わせもしくは誘導体のうち少なくとも１つを含む、［３４］に記載のデバイス。
［３６］ 前記基板は金属または金属箔、たとえば鋼、Ｔｉ、Ａｌ、インコネル合金、またはコバールを含む、［３０］ないし［３５］のいずれか１に記載のデバイス。
［３７］ 前記基板は紙または紙様物質を含む、［３０］ないし［３６］のいずれか１に記載のデバイス。
［３８］ 電極の一方または両方は直接的または間接的に前記基板上に堆積されている、［３０］ないし［３７］のいずれか１に記載のデバイス。
［３９］ 前記第１および第２の電極の一方または両方は導電性で透明または半透明である、［１］ないし［３８］のいずれか１に記載のデバイス。
［４０］ 前記導電性で透明な電極の一方または両方は半透明酸化物、たとえばインジウム錫酸化物、または半透明金属の薄膜、たとえばＡｕ、Ａｇ、Ｐｔ、またはＡｌを含む、［３９］に記載のデバイス。
［４１］ 前記第１および第２の電極の一方または両方は導電性ポリマー、たとえばポリ（３，４−エチレンジオキシチオフェン）−ポリ（スチレンスルホネート）の薄膜で被覆されている、［１］ないし［４０］のいずれか１に記載のデバイス。
［４２］ 前記第１および第２の電極の一方または両方は金属を含む、［１］ないし［４１］のいずれか１に記載のデバイス。
［４３］ 前記電極は安定な金属、たとえばＡｌ、ＡｇまたはＡｕを含む、［４２］に記載のデバイス。
［４４］ ［１］ないし［４３］のいずれか１に記載の発光デバイスと、
前記第１および第２の電極に接続された電源と
を有する、光を発生するためのシステム。
［４５］ 前記電源は発光デバイスの予備バイアスを与えるように設けられている、［４４］に記載のシステム。
［４６］ 前記電源は、実効的なｐ−ｎ接合を形成するのに十分な電圧および／または電流および期間で、予備バイアスを与えるように設けられている、［４５］に記載のシステム。
［４７］ 前記予備バイアスを１時間未満、３０分間未満、２０分間未満、１５分間未満、１０分間未満、５分間未満、１分間未満、３０秒間未満、１５秒間未満、５秒間または１秒間未満の期間の間与える、［４５］または［４６］に記載のシステム。
［４８］ 前記予備バイアスを前記発光デバイスが実質的に初期状態または緩和状態にあるときにのみ与える、［４５］ないし［４７］のいずれか１に記載のシステム。
［４９］ 前記電源は、定格駆動電圧と定格駆動電圧より高い予備バイアス電圧とを与えるように設けられている、［４５］ないし［４７］のいずれか１に記載のシステム。
［５０］ 前記予備バイアス電圧は、定格駆動電圧より約１０％−１０００％高い、定格駆動電圧より約１０％−５００％高い、定格駆動電圧より約１０％−１００％高い、定格駆動電圧より約３０％−１００％高い、または定格駆動電圧より約３０％−５０％高い、［４９］に記載のシステム。
［５１］ 前記電源は、定格駆動電流と定格駆動電流より高い予備バイアス駆動電流とを与えるように設けられている、［４５］ないし［４８］のいずれか１に記載のシステム。
［５２］ 前記予備バイアス電流は、定格駆動電流の約２−１００倍、定格駆動電流の約２−５０倍、定格駆動電流の約２−２０倍、または定格駆動電流の約５−２０倍である、［５１］に記載のシステム。
［５３］ 前記電源は、前記発光デバイスを実質的に定電流で駆動するように設けられている、［４４］ないし［５２］のいずれか１に記載のシステム。
［５４］ 前記電源は、前記発光デバイスに常時接続されるように設けられている、［４４］ないし［５３］のいずれか１に記載のシステム。
［５５］ 光を発生するための、［１］ないし［４３］のいずれか１に記載のデバイスまたは［４４］ないし［５４］のいずれか１に記載のシステムの使用。
［５６］ ［１］ないし［４３］のいずれか１に記載の発光デバイスを操作する方法であって、前記発光デバイスを予備バイアスする方法。
［５７］ 前記予備バイアスを実効的なｐ−ｎ接合を形成するのに十分な電圧および期間で与える、［５６］に記載の方法。
［５８］ 前記予備バイアスを１時間未満、３０分間未満、２０分間未満、１５分間未満、１０分間未満、５分間未満、１分間未満、３０秒間未満、１５秒間未満、５秒間または１秒間未満の期間の間与える、［５６］または［５７］に記載の方法。
［５９］ 前記予備バイアスを前記発光デバイスが実質的に初期状態または緩和状態にあるときに与える、［５６］ないし［５８］のいずれか１に記載の方法。
［６０］ 前記発光デバイスの定格駆動電圧より高い予備バイアス電圧を与える、［５６］ないし［５９］のいずれか１に記載の方法。
［６１］ 前記発光デバイスの定格駆動電流より高い予備バイアス電流を与える、［５６］ないし［６０］のいずれか１に記載の方法。
［６２］ 前記発光デバイスを実質的に定電流で駆動する、［５６］ないし［５９］のいずれか１に記載の方法。
［６３］ 前記予備バイアスを、一部を形成する成分の使用または試験に関連して与える、［５６］ないし［６２］のいずれか１に記載の方法。 Under these special conditions, equation (11) can be rewritten as:

Below, the description of the initial claim of the present application is appended as an embodiment.
[1] A light-emitting device having a first electrode, a second electrode, and a light-emitting active material that contacts and separates the first and second electrodes, the active material comprising:
Comprising a combination of a conjugated polymer and an electrolyte, the electrolyte comprising ions, allowing electrochemical doping of the conjugated polymer;
The ratio of ions to conjugated polymer is selected to allow the formation of (i), (ii)
(I) doped regions at each electrode interface, which enable injection and transport of electronic charge carriers into and through the doped regions, respectively, at zero or low overvoltage, and
(Ii) an effective undoped region that separates the doped region, wherein the injected electronic charge carriers can be recombined by excitation of the conjugated polymer, and the polymer can be deexcited by emission;
The ratio of ions to conjugated polymer is low enough so that the undoped region remains effectively undoped and does not contain the ions, and substantially all ions in the active material are confined to the doped region; Light emitting device.
[2] The device according to [1], wherein the conjugated polymer is hydrophobic and the electrolyte is hydrophilic, or the conjugated polymer is hydrophilic and the electrolyte is hydrophobic.
[3] The device according to [1], wherein the conjugated polymer and the electrolyte form a phase-separated mixture, and the components are separated on a scale ranging from 1 nm to 1 mm.
[4] The device according to [3], wherein the components are separated on a scale ranging from about 50 nm to about 100 μm, or from about 400 nm to about 10 μm.
[5] The device according to [1], wherein the combination is a substantially single-phase combination.
[6] The ratio of ions to conjugated polymer is selected to provide an undoped region width that effectively eliminates deleterious interactions between the excited conjugated polymer and doped region dopants and ions. [1] The device according to any one of [4].
[7] The electrodes at least partially overlap each other, and the ratio of the ions to the conjugated polymer is such that the width of the effectively undoped region is about 10 nm to 200 nm, or about 10-100 nm, or about 10-50 nm or about The device according to [6], which is selected to be 20 nm.
[8] The ratio of the mass of the salt providing the ion to the mass of the conjugated polymer is about 0.01-3 times, or about 0.1-3 times, or about 0.5, calculated according to the following formula: -2 times or about 0.5-1 times selected,

(Where x _doping is the doping concentration in the doped region, d _tot is the total distance between the electrodes, d _pn is the width of the undoped region (in the direction between the electrodes), and M _salt is the molar mass of the salt. And M _CPru is the molar mass of the repeating unit of the conjugated polymer)
[7] The device.
[9] The ratio of the mass of the ion to the mass of the conjugated polymer is about 0.005-0.10, or about 0.01-0.06, any one of [1] to [8] device.
[10] The electrodes are substantially coplanar, and the ratio of the ions to the conjugated polymer is such that the effective undoped region width is about 10 nm to 70 μm, or about 100 nm to 70 μm, or about 1 μm. The device according to any one of [1] to [6], which is selected to be about 70 μm, or about 10 μm to 70 μm, or about 10 μm to 20 μm.
[11] The ratio of the ions to the conjugated polymer is at least 20 hours of continuous operation, at least 40 hours of continuous operation, at least 60 hours of continuous operation, at least 80 hours of continuous operation, at least 100 hours. in continuous operation, a continuous operation of at least 150 hours, or continuous operation of at least 200 hours, or providing the luminance exceeding 100 cd / ^{m 2} in a continuous operation of at least one month, or at least 4 months 20 cd / ^{m 2} Any of [1] to [10], selected to maintain a brightness greater than , to maintain a brightness greater than 400 cd / m ² for at least 4 days , or to maintain a brightness greater than 1000 cd / m ² for at least 24 hours The device according to 1.
[12] The conjugated polymer includes poly (paraphenylene vinylene (PPV), polyfluorenylene (PF), poly (1,4-phenylene) (PP), polythiophene (PT), and neutral and ionic derivatives thereof. The device according to any one of [1] to [11], which is selected from the group consisting of:
[13] The device according to [12], wherein the conjugated polymer is poly [2-methoxy-5- (2-ethyl-hexyloxy) -1,4-phenylenevinylene].
[14] The device according to any one of [1] to [12], wherein the conjugated polymer comprises a phenyl-substituted PPV copolymer, for example, super yellow.
[15] The device according to any one of [1] to [14], wherein the electrolyte includes a gel electrolyte.
[16] The device according to any one of [1] to [15], wherein the electrolyte includes a substantially solid electrolyte.
[17] The device according to any one of [1] to [16], wherein the electrolyte includes a substantially liquid electrolyte.
[18] The device according to any one of [1] to [17], further comprising a spacer provided to maintain a predetermined distance between the electrodes.
[19] The device according to any one of [1] to [18], wherein the electrolyte includes a salt.
[20] The salt comprises at least one metal salt, the salt comprising a cation, such as Li, Na, K, Rb, Mg, or Ag, and a molecular anion, such as CF ₃ SO ₃ , ClO ₄ , or (CF ₃ SO ₂ ) ₂ N, The device according to [19].
[21] The device according to any one of [1] to [20], wherein the electrolyte in the active material includes an ion-soluble substance.
[22] The concentration of the ion-soluble substance is sufficiently high to allow ion dissociation, and at least 80 hours of continuous operation for at least 20 hours, at least 40 hours of continuous operation, at least 60 hours of continuous operation. Giving a brightness of more than 100 cd / m ² in continuous operation for hours, in continuous operation for at least 100 hours, in continuous operation for at least 150 hours, or in continuous operation for at least 200 hours, or in continuous operation for at least one month ; or maintain at least 4 months 20 cd / ^m brightness greater than ^2, to maintain the brightness of greater than at least 4 days 400 cd / ^{m 2,} or sufficiently low to maintain at least a luminance of greater than 24 hours 1000 cd / ^{m 2,} [ 21].
[23] The mass ratio of the ion-soluble substance to the conjugated polymer is about 0.01-0.25, about 0.01-0.20, about 0.01-0.17, about 0.05-. 0.25, about 0.05-0.20, about 0.05-0.17, about 0.08-0.25, about 0.08-0.20, or about 0.085-0.17. [21] or [22].
[24] The device according to any one of [21] to [23], wherein the ion-soluble substance includes at least one polymer substance.
[25] The device of [24], wherein the polymeric material is selected from the group consisting of poly (ethylene oxide), poly (propylene oxide), methoxyethoxy-ethoxy substituted polyphosphazan, and polyether-based polyurethane, or combinations thereof. .
[26] The device of any one of [21] to 23], wherein the ionic soluble material comprises at least one non-polymeric ionic soluble material, such as a crown ether.
[27] The device according to any one of [1] to [26], wherein the electrolyte includes at least one ionic liquid.
[28] The device according to any one of [1] to [27], wherein the active material includes a surfactant or a polymer non-ionic soluble material, such as polystyrene.
[29] The device according to any one of [1] to [28], wherein the electrolyte includes KCF ₃ SO ₃ dissolved in poly (ethylene oxide) .
[30] The device according to any one of [1] to [29], wherein the device is formed on a substrate.
[31] The device according to [30], wherein the substrate is effectively non-flexible.
[32] The device according to [31], wherein the substrate includes glass or a glass-like substance.
[33] The device according to [30], wherein the substrate is effectively flexible.
[34] The device of [33], wherein the substrate comprises a polymer material.
[35] The [34], wherein the polymeric material comprises at least one of poly (ethylene terephthalate), poly (ethylene naphthalate), poly (imide), poly (carbonate), or combinations or derivatives thereof. device.
[36] The device according to any one of [30] to [35], wherein the substrate includes a metal or a metal foil, such as steel, Ti, Al, an Inconel alloy, or Kovar.
[37] The device according to any one of [30] to [36], wherein the substrate includes paper or a paper-like substance.
[38] The device according to any one of [30] to [37], wherein one or both of the electrodes are directly or indirectly deposited on the substrate.
[39] The device according to any one of [1] to [38], wherein one or both of the first and second electrodes are conductive, transparent, or translucent.
[40] One or both of the conductive transparent electrodes comprise a translucent oxide, such as indium tin oxide, or a translucent metal thin film, such as Au, Ag, Pt, or Al. Devices.
[41] One or both of the first and second electrodes are coated with a thin film of a conductive polymer, such as poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate), [1] to [40] The device according to any one of [40].
[42] The device according to any one of [1] to [41], wherein one or both of the first and second electrodes includes a metal.
[43] The device of [42], wherein the electrode comprises a stable metal, such as Al, Ag or Au.
[44] The light-emitting device according to any one of [1] to [43];
A power source connected to the first and second electrodes;
A system for generating light.
[45] The system of [44], wherein the power source is provided to provide a preliminary bias of the light emitting device.
[46] The system of [45], wherein the power supply is provided to provide a pre-bias at a voltage and / or current and duration sufficient to form an effective pn junction.
[47] The preliminary bias is less than 1 hour, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 1 minute, less than 30 seconds, less than 15 seconds, less than 5 seconds or less than 1 second. The system according to [45] or [46], which is given for a period of time.
[48] The system according to any one of [45] to [47], wherein the preliminary bias is applied only when the light emitting device is substantially in an initial state or a relaxed state.
[49] The system according to any one of [45] to [47], wherein the power supply is provided to provide a rated drive voltage and a preliminary bias voltage higher than the rated drive voltage.
[50] The preliminary bias voltage is about 10% -1000% higher than the rated drive voltage, about 10% -500% higher than the rated drive voltage, about 10% -100% higher than the rated drive voltage, about The system of [49], which is 30% -100% higher or about 30-50% higher than the rated drive voltage.
[51] The system according to any one of [45] to [48], wherein the power supply is provided to provide a rated drive current and a preliminary bias drive current higher than the rated drive current.
[52] The preliminary bias current is about 2-100 times the rated drive current, about 2-50 times the rated drive current, about 2-20 times the rated drive current, or about 5-20 times the rated drive current. The system according to [51].
[53] The system according to any one of [44] to [52], wherein the power source is provided to drive the light emitting device with a substantially constant current.
[54] The system according to any one of [44] to [53], wherein the power source is provided so as to be always connected to the light emitting device.
[55] Use of the device according to any one of [1] to [43] or the system according to any one of [44] to [54] to generate light.
[56] A method for operating the light emitting device according to any one of [1] to [43], wherein the light emitting device is pre-biased.
[57] The method according to [56], wherein the preliminary bias is applied at a voltage and a period sufficient to form an effective pn junction.
[58] The preliminary bias is less than 1 hour, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 1 minute, less than 30 seconds, less than 15 seconds, less than 5 seconds or less than 1 second. The method according to [56] or [57], which is given for a period of time.
[59] The method of any one of [56] to [58], wherein the preliminary bias is applied when the light emitting device is substantially in an initial state or a relaxed state.
[60] The method according to any one of [56] to [59], wherein a pre-bias voltage higher than a rated driving voltage of the light emitting device is applied.
[61] The method according to any one of [56] to [60], wherein a preliminary bias current higher than a rated drive current of the light emitting device is provided.
[62] The method according to any one of [56] to [59], wherein the light emitting device is driven with a substantially constant current.
[63] The method of any one of [56] to [62], wherein the pre-bias is provided in connection with the use or testing of a component that forms part.

Claims (63)

A light-emitting device having a first electrode, a second electrode, and a light-emitting active material that contacts and separates the first and second electrodes, the active material comprising:
Comprising a combination of a conjugated polymer and an electrolyte, the electrolyte comprising ions, allowing electrochemical doping of the conjugated polymer;
The ratio of ions to conjugated polymer is selected to allow the formation of (i), (ii)
(I) doped regions at each electrode interface, which allow injection and transport of electronic charge carriers into and through the doped regions, respectively, at zero or low overvoltage, and (ii) doped regions An effective undoped region that separates the injected electron charge carriers can be recombined by excitation of the conjugated polymer, and the polymer can be de-excited by emission.
The ratio of ions to conjugated polymer is low enough so that the undoped region remains effectively undoped and does not contain the ions, and substantially all ions in the active material are confined to the doped region; Light emitting device.   The device of claim 1, wherein the conjugated polymer is hydrophobic and the electrolyte is hydrophilic, or the conjugated polymer is hydrophilic and the electrolyte is hydrophobic.   The device of claim 1, wherein the conjugated polymer and the electrolyte form a phase separated mixture, the components of which are separated on a scale in the range of 1 nm to 1 mm.   4. The device of claim 3, wherein the components are separated on a scale in the range of about 50 nm to about 100 μm, or about 400 nm to about 10 μm.   The device of claim 1, wherein the combination is a substantially single phase combination.   The ratio of the ions to the conjugated polymer is selected to provide an undoped region width that effectively eliminates deleterious interactions between the excited conjugated polymer and doped region dopants and ions. 5. The device according to any one of 4.   The electrodes at least partially overlap one another and the ratio of the ions to the conjugated polymer is such that the effective undoped region width is about 10 nm to 200 nm, or about 10-100 nm, or about 10-50 nm, or about 20 nm. The device of claim 6, selected as follows: The ratio of the mass of the salt that gives the ions to the mass of the conjugated polymer is about 0.01-3 times, or about 0.1-3 times, or about 0.5-2 times z calculated according to the following formula: Or about 0.5-1 times selected,

(Where x _doping is the doping concentration in the doped region, d _tot is the total distance between the electrodes, d _pn is the width of the undoped region (in the direction between the electrodes), and M _salt is the molar mass of the salt. And M _CPru is the molar mass of the repeating unit of the conjugated polymer)
The device of claim 7.   9. The device of any one of claims 1 to 8, wherein the ratio of the mass of ions to the mass of the conjugated polymer is about 0.005-0.10, or about 0.01-0.06.   The electrodes are substantially coplanar, and the ratio of the ions to the conjugated polymer is such that the width of the effectively undoped region is about 10 nm to 70 μm, or about 100 nm to 70 μm, or about 1 μm to 70 μm, 7. A device according to any one of the preceding claims, wherein the device is selected to be about 10 μm to 70 μm, or about 10 μm to 20 μm. The ratio of the ions to the conjugated polymer is at least 20 hours of continuous operation, at least 40 hours of continuous operation, at least 60 hours of continuous operation, at least 80 hours of continuous operation, at least 100 hours of continuous operation. in continuous operation of at least 150 hours, or continuous operation of at least 200 hours, or at least provide the luminance exceeding 100 cd / ^{m 2} 1 or monthly continuous operation, or at least 4 or brightness of greater than monthly 20 cd / ^{m 2} 11. The method according to any one of claims 1 to 10, selected to maintain, maintain a brightness exceeding 400 cd / m ² for at least 4 days, or maintain a brightness exceeding 1000 cd / m ² for at least 24 hours. device.   The conjugated polymer comprises poly (paraphenylene vinylene (PPV), polyfluorenylene (PF), poly (1,4-phenylene) (PP), polythiophene (PT), and neutral and ionic derivatives thereof. The device according to claim 1, wherein the device is more selected.   The device of claim 12, wherein the conjugated polymer is poly [2-methoxy-5- (2-ethyl-hexyloxy) -1,4-phenylenevinylene].   13. A device according to any one of the preceding claims, wherein the conjugated polymer comprises a phenyl substituted PPV copolymer, e.g. super yellow.   The device according to claim 1, wherein the electrolyte includes a gel electrolyte.   16. A device according to any one of the preceding claims, wherein the electrolyte comprises a substantially solid electrolyte.   17. A device according to any one of the preceding claims, wherein the electrolyte comprises a substantially liquid electrolyte.   The device according to any one of claims 1 to 17, further comprising a spacer provided to maintain a predetermined distance between the electrodes.   The device according to claim 1, wherein the electrolyte contains a salt. The salt comprises at least one metal salt, the salt comprising a cation, such as Li, Na, K, Rb, Mg, or Ag, and a molecular anion, such as CF ₃ SO ₃ , ClO ₄ , or (CF ₃ SO ₂ ). and a ₂ N, a device according to claim 19.   The device according to any one of claims 1 to 20, wherein the electrolyte in the active material contains an ion-soluble substance. The concentration of the ion-soluble substance is sufficiently high to allow ion dissociation and is continuous for at least 20 hours, continuously for at least 40 hours, continuously for at least 60 hours, and continuously for at least 80 hours. In operation, at least 100 hours of continuous operation, at least 150 hours of continuous operation, or at least 200 hours of continuous operation, or at least one month of continuous operation, giving a brightness greater than 100 cd / m ² , or at least 4 either maintain the brightness of greater than monthly 20 cd / ^{m 2,} to maintain the brightness of greater than at least 4 days 400 cd / ^{m 2,} or sufficiently low to maintain at least a luminance of greater than 24 hours 1000 cd / ^{m 2,} to claim 21 The device described.   The mass ratio of the ion-soluble substance to the conjugated polymer is about 0.01-0.25, about 0.01-0.20, about 0.01-0.17, about 0.05-0.25. About 0.05-0.20, about 0.05-0.17, about 0.08-0.25, about 0.08-0.20, or about 0.085-0.17. The device according to 21 or 22.   24. A device according to any one of claims 21 to 23, wherein the ion soluble material comprises at least one polymeric material.   25. The device of claim 24, wherein the polymeric material is selected from the group consisting of poly (ethylene oxide), poly (propylene oxide), methoxyethoxy-ethoxy substituted polyphosphazan, and polyether-based polyurethane, or combinations thereof.   24. A device according to any one of claims 21 to 23, wherein the ionic soluble material comprises at least one non-polymeric ionic soluble material, e.g. crown ether.   27. A device according to any one of claims 1 to 26, wherein the electrolyte comprises at least one ionic liquid.   28. A device according to any one of the preceding claims, wherein the active material comprises a surfactant or a polymeric non-ionic soluble material, such as polystyrene. The electrolyte includes a _KCF 3 SO ₃ dissolved in poly (ethylene oxide), according to any one of claims 1 to 28 devices.   30. A device according to any one of claims 1 to 29, wherein the device is formed on a substrate.   32. The device of claim 30, wherein the substrate is effectively non-flexible.   32. The device of claim 31, wherein the substrate comprises glass or a glass-like material.   32. The device of claim 30, wherein the substrate is effectively flexible.   34. The device of claim 33, wherein the substrate comprises a polymeric material.   35. The device of claim 34, wherein the polymeric material comprises at least one of poly (ethylene terephthalate), poly (ethylene naphthalate), poly (imide), poly (carbonate), or combinations or derivatives thereof.   36. A device according to any one of claims 30 to 35, wherein the substrate comprises a metal or metal foil, such as steel, Ti, Al, an Inconel alloy or Kovar.   37. A device according to any one of claims 30 to 36, wherein the substrate comprises paper or paper-like material.   38. A device according to any one of claims 30 to 37, wherein one or both of the electrodes are directly or indirectly deposited on the substrate.   39. A device according to any preceding claim, wherein one or both of the first and second electrodes are conductive, transparent or translucent.   40. The device of claim 39, wherein one or both of the conductive transparent electrodes comprises a translucent oxide, such as indium tin oxide, or a thin film of translucent metal, such as Au, Ag, Pt, or Al.   41. Any of the first and second electrodes are coated with a thin film of a conductive polymer such as poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonate). The device according to claim 1.   42. The device of any one of claims 1-41, wherein one or both of the first and second electrodes comprises a metal.   43. The device of claim 42, wherein the electrode comprises a stable metal, such as Al, Ag or Au. A light emitting device according to any one of claims 1 to 43;
A system for generating light having a power source connected to the first and second electrodes.   45. The system of claim 44, wherein the power source is provided to provide a preliminary bias for the light emitting device.   46. The system of claim 45, wherein the power source is provided to provide a pre-bias at a voltage and / or current and duration sufficient to form an effective pn junction.   The pre-bias for a period of less than 1 hour, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 1 minute, less than 30 seconds, less than 15 seconds, less than 5 seconds or less than 1 second 47. A system according to claim 45 or 46.   48. The system of any one of claims 45 to 47, wherein the pre-bias is provided only when the light emitting device is substantially in an initial state or a relaxed state.   48. A system according to any one of claims 45 to 47, wherein the power source is provided to provide a rated drive voltage and a pre-bias voltage higher than the rated drive voltage.   The preliminary bias voltage is about 10% to 1000% higher than the rated driving voltage, about 10% to 500% higher than the rated driving voltage, about 10% to 100% higher than the rated driving voltage, and about 30% higher than the rated driving voltage. 50. The system of claim 49, wherein the system is 100% higher or about 30% -50% higher than a rated drive voltage.   49. A system according to any one of claims 45 to 48, wherein the power source is provided to provide a rated drive current and a pre-bias drive current that is higher than the rated drive current.   The pre-bias current is about 2-100 times rated drive current, about 2-50 times rated drive current, about 2-20 times rated drive current, or about 5-20 times rated drive current. Item 52. The system according to Item 51.   53. A system according to any one of claims 44 to 52, wherein the power source is provided to drive the light emitting device at a substantially constant current.   54. The system according to any one of claims 44 to 53, wherein the power source is provided so as to be always connected to the light emitting device.   55. Use of a device according to any one of claims 1 to 43 or a system according to any one of claims 44 to 54 for generating light.   44. A method of operating a light emitting device according to any one of claims 1 to 43, wherein the light emitting device is pre-biased.   57. The method of claim 56, wherein the pre-bias is applied at a voltage and duration sufficient to form an effective pn junction.   The pre-bias for a period of less than 1 hour, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 1 minute, less than 30 seconds, less than 15 seconds, less than 5 seconds or less than 1 second 58. A method according to claim 56 or 57, wherein:   59. A method according to any one of claims 56 to 58, wherein the pre-bias is applied when the light emitting device is substantially in an initial state or a relaxed state.   60. A method according to any one of claims 56 to 59, wherein a pre-bias voltage higher than a rated drive voltage of the light emitting device is provided.   61. A method according to any one of claims 56 to 60, wherein a pre-bias current higher than a rated drive current of the light emitting device is provided.   60. A method according to any one of claims 56 to 59, wherein the light emitting device is driven with a substantially constant current.   63. A method according to any one of claims 56 to 62, wherein the pre-bias is provided in connection with the use or testing of a component that forms part.

Images