Light-emitting electrochemical cell, security element, security system, method of operation and method of production

1 . A light-emitting electrochemical cell, comprising:

a substrate,

a first electrode,

an emission layer, contacting the first electrode and providing a first two-dimensional (2D) pattern, which is made up by the emission layer being visually distinguishable from the substrate and/or one or more components associated with the light-emitting electrochemical cell, and

a second electrode,

wherein the emission layer provides a second 2D pattern, which is made up by first portions which are passive with respect to photoluminescence and second portions of the emission layer which are active with respect to photoluminescence, and

wherein a third 2D pattern is provided by regions, which are active with respect to electroluminescence, where the first and second electrodes overlap and electrically contact the second portions of the emission layer.

2 . The light-emitting electrochemical cell as claimed in claim 1 , wherein the light-emitting electrochemical cell is configured such that the second 2D pattern is visually distinguishable when at least the second portions are optically excited to photoluminescence.

3 . The light-emitting electrochemical cell as claimed in claim 1 , wherein the light-emitting electrochemical cell is configured such that the third 2D pattern is visually distinguishable when an electrical potential is applied between the electrodes, and

wherein the application of the electrical potential between the electrodes at least partially quenches photoluminescence of said regions,

such that a fourth 2D pattern is visually distinguishable after the electrical potential has been removed and at least the second portions of the second 2D pattern are excited to photoluminescence.

4 . The light-emitting electrochemical cell as claimed in claim 3 , wherein the light-emitting electrochemical cell is configured such that a temporal transition from the fourth 2D pattern to the second 2D pattern, following electrical operation of the light-emitting electrochemical cell, is detectable by excitation of at least second portions of the second 2D pattern to photoluminescence.

5 . The light-emitting electrochemical cell as claimed in claim 1 , further comprising an insulating layer, which is selectively provided between the emission layer and one of the electrodes, such that the third 2D pattern, is at least partially determined by the insulating layer,

wherein the insulating layer is formed from a material selected from a group consisting of polymers, ceramics, and glasses.

6 . The light-emitting electrochemical cell as claimed in claim 1 , wherein the emission layer comprises a blend of one or more organic and/or inorganic semiconductors and one or more sources of mobile ions,

wherein the organic semiconductor is selected from a group consisting of non-ionic and ionic transition-metal complexes, conjugated polymers, conjugated small molecules, organic, carbon and perovskite quantum dots, and various types of specialty emitters featuring thermally activated delayed-fluorescence, or wherein the inorganic semiconductor is selected from a group consisting of inorganic quantum dots and perovskites, and the mobile ions are selected from a group comprising salts dissolved in ion-dissolving compounds and ionic liquids;

wherein the substrate is formed from one or more materials selected from the group consisting of glasses, polymers, pulp-based materials, metallic materials and meshes, and moisture and oxygen barrier materials; and

wherein at least one of the electrodes is formed from one or more materials selected from a group consisting of metals, doped and pristine inorganic semiconductors, doped and pristine organic semiconductors, and polymers, the one or more materials being provided in the form of films, sintered particles, sintered nanoparticles, wires, nanowires, flakes, or wire meshes.

7 . A security element, comprising a light-emitting electrochemical cell as claimed in claim 1 , and a power supply, which is operatively coupled to the first and second electrodes, for selective activation of the light-emitting electrochemical cell.

8 . A security system, comprising:

a security element as claimed in claim 7 , and

an excitation light source configured to provide light of a wavelength range for causing photoluminescence in the emission layer,

further comprising:

at least one image capture device, and

at least one processing device, configured to:

receive data from the image capture device, the image representing at least part of an emission layer area of the security element, and

processing the data to determine authenticity of the security element.

9 . A method of operating a light-emitting electrochemical cell comprising:

a substrate,

a first electrode,

an emission layer, contacting the first electrode and providing a first two-dimensional (2D) pattern, which is made up by the emission layer being visually distinguishable from the substrate and/or one or more components associated with the light-emitting electrochemical cell, and

a second electrode,

wherein the emission layer provides a second 2D pattern, which is made up by first portions which are passive with respect to photoluminescence and second portions of the emission layer which are active with respect to photoluminescence,

wherein a third 2D pattern is provided by regions, which are active with respect to electroluminescence, where the first and second electrodes overlap and electrically contact the second portions of the emission layer,

the method comprising:

providing the light-emitting electrochemical cell with only the first 2D pattern being visually distinguishable,

exposing the light-emitting electrochemical cell to first excitation light, whereby the second portions of the emission layer are caused to provide photoluminescence, such that the second 2D pattern becomes visually distinguishable, and

electrically operating the light-emitting electrochemical cell so as to cause electroluminescence in said emission layer by applying an electric potential across the electrodes, such that the third 2D pattern becomes visually distinguishable.

10 . The method as claimed in claim 9 , further comprising:

stopping the electrical operation of the light-emitting electrochemical cell, and

subsequent to said electrical operation, exposing the light-emitting electrochemical cell to second excitation light, such that a fourth 2D pattern becomes visually distinguishable, said fourth 2D pattern corresponding to the second 2D pattern and an inverse of the third 2D pattern.

11 . The method as claimed in claim 10 , further comprising capturing a fourth image representing the light-emitting electrochemical cell during said exposure of the light-emitting electrochemical cell to said second excitation light.

12 . The method as claimed in claim 11 , further comprising capturing fourth spectral data representing photoluminescence from at least part of the light emitting electrochemical cell during said exposure of the light emitting electrochemical cell to said second excitation light.

13 . The method as claimed in claim 9 , wherein the electrical operation comprises one of reversibly quenching a photoluminescence capacity of the regions, and permanently quenching the photoluminescence capacity of the regions.

14 . The method as claimed in claim 9 , further comprising capturing a first image representing the light-emitting electro-chemical cell while the light-emitting electrochemical cell is exposed to at least non-excitation light and prior to said exposing of the light-emitting electrochemical cell to the first excitation light, and capturing a second image representing the light-emitting electrochemical cell during said exposing of the light-emitting electrochemical cell to the first excitation light, and

wherein capturing said first and/or second image comprises capturing first spectral data and/or second spectral data representing light emission from at least part of the light-emitting electrochemical cell during said exposing of the light-emitting electrochemical cell to the first excitation light.

15 . The method as claimed in claim 9 , further comprising at least one of:

capturing at least one emission intensity transient directly following said exposing of the light-emitting electrochemical cell to the first excitation light, thus enabling a distinction between fast-decaying fluorescence and comparatively slow-decaying phosphorescence;

capturing a third image representing the light-emitting electrochemical cell during said electroluminescence; and

capturing third spectral data representing light emission from at least part of the light-emitting electrochemical cell during said electroluminescence.

16 . The method as claimed in claim 9 , wherein said electrical operation is performed according to one of the following:

electrical operation is performed subsequently to said exposure of the light-emitting electrochemical cell to the first excitation light; and

said electrical operation is performed prior to said exposure of the light emitting electrochemical cell to the first excitation light.

17 . The method as claimed in claim 9 , further comprising capturing at least two images representing the photoluminescence from the light-emitting electrochemical cell, during said exposure of the light-emitting electrochemical cell to the second excitation light, at different points in time,

wherein said points in time occur during a recovery phase in which the photoluminescence recovers from an electrochemical doping quenching, and

wherein spectral data are captured for at least some of the images representing the light-emitting electrochemical cell at different points in time during a recovery phase, during which said photoluminescence recovers.

18 . A method of manufacturing a light-emitting electrochemical cell, comprising:

providing a substrate,

depositing a first electrode on the substrate,

depositing an emission layer, which contacts and at least partially overlaps the first electrode, to provide a first two-dimensional (2D) pattern, which is made up by emission layer being visually distinguishable from the substrate and/or one or more components associated with the light-emitting electrochemical cell,

providing a second 2D pattern, which is made up by first portions which are passive with respect to photoluminescence and second portions of the emission layer which are active with respect to photoluminescence, and

depositing a second electrode, which contacts and at least partially overlaps the emission layer, and which at least partially overlaps the first electrode, to form regions which are active with respect to electroluminescence.

19 . The method as claimed in claim 18 , wherein said providing the second 2D pattern comprises providing deactivated portions of the emission layer by selectively deactivating portions of the deposited emission layer.

20 . The method as claimed in claim 18 , wherein said providing the second 2D pattern comprises providing deactivated portions by selectively depositing non-active material with respect to photoluminescence.

21 . The method as claimed in claim 18 , wherein the electrodes are selectively deposited with an overlap and with electrical contact with the portions of the emission layer with its photoluminescence being active, according to a third 2D pattern.

22 . The method as claimed in claim 18 , further comprising selectively depositing at least one insulating layer between the active material layer and one of the electrodes.

23 . The method as claimed in claim 22 , wherein the insulating layer is selectively deposited according to a third 2D pattern.