Method for producing an optoelectronic device

Abstract

The present description relates to an organic light-emitting diode (100), comprising an emissive layer (150), emitting at a first wavelength, arranged between an electron injection layer (132) and a hole injection layer (131), wherein at least one of the electron injection layer (132) or the hole injection layer (131) is a layer of a first inorganic perovskite material. The invention also relates to an OLED screen or an OLED microscreen comprising such OLEDs, as well as to methods for producing same. A top electrode (122) and / or spectral conversion elements (161, 162) may be formed by PLD on the previously described layers.

Description

DESCRIPTION Method for manufacturing an optoelectronic device This application is based on, and claims priority from, French patent application number FR 24 / 12205 filed on November 7, 2024, entitled "Method for manufacturing an optoelectronic device", which is considered to form an integral part of this description within the limits provided by law. technical field

[0001] This description relates generally to the field of organic optoelectronic devices, particularly display, lighting, and signaling devices. The invention relates more specifically to organic light-emitting diode (OLED) devices such as displays or microdisplays. Previous technique

[0002] An OLED is formed from a stack of organic semiconductor layers, including at least one emissive (electroluminescent) layer, positioned between a hole-carrying layer and an electron-carrying layer. The stack is located between two electrodes, most often metallic. A hole-carrying layer and an electron-carrying layer allow electrons and holes to be injected into the organic stack when a potential difference is applied between the electrodes. The holes and electrons are then transmitted and recombine radiatively within the emissive layer.

[0003] To form color screens, different color conversion elements, typically quantum dots (also called quantum dots or QDs for 'quantum dots') are used to convert, for example, the blue light emitted by the OLED into green and red light.

[0004] In the case of top emission, the emitted photons pass through the upper electrode (the cathode) which must be both conductive and transparent (or made of a material thin enough to be transparent).

[0005] However, the organic layer of OLEDs is sensitive not only to atmospheric oxygen and humidity but also to temperature. Therefore, an encapsulation layer is generally used to protect it from the environment.

[0006] In addition, the top electrode must be deposited at a low temperature to avoid damaging the underlying organic stack, which often reduces the quality of the deposited material and therefore the performance of the final device. Summary of the invention

[0007] There is a need for a manufacturing process for a device that overcomes the drawbacks of the prior art and allows, in particular, for good performance.

[0008] This goal is achieved by an organic light-emitting diode comprising an emissive layer, emitting at a first wavelength, disposed between an electron injection layer and a hole injection layer, at least one of the electron injection layer or of the hole injection layer being a layer in a first inorganic perovskite material.

[0009] According to a particular embodiment, the other of the electron injection layer or hole injection layer is a layer of a second inorganic perovskite material.

[0010] According to a particular embodiment, the organic light-emitting diode comprises a substrate successively coated by: - a first electrode, - the hole injection layer, - a layer for transporting holes, - the emissive layer, - an electron transport layer, the electron injection layer, in the first inorganic perovskite material, - a second electrode made of a transparent conductive oxide, for example indium tin oxide.

[0011] According to a particular embodiment, a first additional layer, for example in oxide, in particular in tungsten oxide, is in contact with the first layer of inorganic perovskite material so as to form a bilayer and / or a second additional layer, for example in oxide, in particular in tungsten oxide, is in contact with the second layer of inorganic perovskite material so as to form another bilayer.

[0012] This goal is also achieved by an optoelectronic device, for example, an OLED microdisplay or an OLED display, comprising successively: - a substrate, with the first structured electrodes arranged on the substrate, defining blue pixels, red pixels, and green pixels, - a layer of hole injection covering the first electrodes, - a layer for transporting holes, - an emitting layer, emitting at a first wavelength, - an electron transport layer, - an electron injection layer, - a spectral conversion element positioned directly above one of the first electrodes defining the red pixel, absorbing at the first wavelength and emitting at a second wavelength greater than the first wavelength and an additional spectral conversion element disposed above one of the first electrodes delimiting the green pixel, absorbing at the first wavelength and emitting at a third wavelength greater than the first wavelength, at least one of the electron injection layer or hole injection layer being a layer in a first inorganic perovskite material and, preferably, the other of the electron injection layer or hole injection layer being a layer in a second inorganic perovskite material.

[0013] According to a particular embodiment, the first layer of inorganic perovskite material is the electron injection layer, the device further comprising a second electrode of conductive transparent oxide, for example in indium tin oxide, the second electrode covering the spectral conversion element and the additional spectral conversion element, or the second electrode being disposed between, on the one hand, the electron injection layer and, on the other hand, the spectral conversion element and the additional spectral conversion element.

[0014] According to a particular embodiment, the spectral conversion element is in a third inorganic perovskite material and the additional spectral conversion element is in a fourth inorganic perovskite material.

[0015] This goal is also achieved by a manufacturing process for an organic light-emitting diode comprising an emissive layer, emitting at a first wavelength, arranged between an injection layer electron and hole injection layer, the process comprising a step in which at least one of the electron injection layer or hole injection layer is formed by depositing a first inorganic perovskite material by PLD.

[0016] According to a particular embodiment, the other of the electron injection layer or hole injection layer is formed by depositing a second inorganic perovskite material, preferably by PLD.

[0017] According to a particular embodiment, a top electrode made of a transparent conductive oxide, for example in indium tin oxide, is deposited by PLD on the stack comprising the emissive layer, the electron injection layer and the hole injection layer.

[0018] This goal is also achieved by a manufacturing process for an optoelectronic device, including the implementation of the manufacturing process for an OLED as described previously, to manufacture several OLEDs on a substrate, and in which spectral conversion elements in perovskite material are deposited on the OLEDs by PLD. Brief description of the drawings

[0019] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the attached figures, among which:

[0020] Figure IA and Figure IB schematically and in cross-section represent a light-emitting diode according to different particular embodiments of the invention.

[0021] Figures 2, 3, and 4 schematically and in cross-section represent various optoelectronic devices according to different particular embodiments of the invention.

[0022] Figure 5A, Figure 5B, Figure 5C and Figure 5D schematically represent different stages of a first part of a manufacturing process for an optoelectronic device, according to a particular embodiment of the invention;

[0023] Figure 6A and Figure 6B schematically represent different stages of a second part of a manufacturing process for an optoelectronic device, according to a particular embodiment of the invention;

[0024] Figure 7A and Figure 7B schematically represent different stages of a second part of a manufacturing process for an optoelectronic device, according to another particular embodiment of the invention.

[0025] The different elements are not necessarily represented at a uniform scale to make the figures more legible. Description of the implementation methods

[0026] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0027] For the sake of clarity, only the steps and elements useful for understanding the implementation methods described have been represented and are detailed.

[0028] Unless otherwise specified, when referring to two connected elements, this means directly connected without any intermediate elements other than conductors, and when referring to two coupled elements, this means that These two elements can be connected or linked via one or more other elements.

[0029] In the description that follows, when referring to absolute positional qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative positional qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientational qualifiers, such as the terms "horizontal", "vertical", etc., unless otherwise specified, it refers to the orientation of the figures.

[0030] Unless otherwise specified, the expressions "approximately", "roughly", "about", and "on the order of" mean at 10%, preferably at 5%.

[0031] A perovskite material is defined as a material with the formula ABX3, where A represents a cation or a mixture of metallic cations preferably chosen from Cs, Rb, K, and Na; B a metallic cation preferably chosen from Pb, Sn, and Ge; and X a halogen preferably chosen from Cl, Br, and I. The perovskite material is a halogenated perovskite material (in other words, it contains at least one halogen). The perovskite materials described are inorganic perovskite materials. They have, for example, the following formula: - for injection layers: CsPbCl3et - for conversion elements: CsPbBr3 or CsPbI3Br.

[0032] At least one of the inorganic perovskite materials used for the injection layer(s) and / or the conversion element(s) is a halogenated inorganic perovskite material. Preferably, each inorganic perovskite material is a halogenated inorganic perovskite material. Preferably, at least one of the injection layers and at least one of the conversion elements are made of halogenated inorganic perovskite material.

[0033] Transparency is defined as a structure or element with a transmittance greater than or equal to 70%, preferably greater than or equal to 80%, and even more preferably greater than or equal to 90%. Transmittance represents the intensity of light passing through the element or structure across the visible spectrum. It can be measured by UV-Vis-IR spectroscopy. Visible spectrum transmittance corresponds to the transmittance for wavelengths between 350 and 800 nm.

[0034] Spectral conversion elements are devices that convert, at least partially, the excitation light they receive into emitted light of a longer wavelength. For example, they can be adapted to absorb blue light, i.e., light with a wavelength between approximately 440nm and 490nm, and emit green light, i.e., light with a wavelength between approximately 495nm and 560nm, or even red light, i.e., light with a wavelength between 600nm and 650nm.

[0035] By "between X and Y", we mean that the limits X and Y are included.

[0036] A bilayer is defined as an element comprising two layers arranged one on top of the other and in direct contact. In other words, there is no intermediate layer between the two layers of the bilayer.

[0037] We will first describe an organic light-emitting diode (OLED) with reference to Figure IA and Figure IB.

[0038] An OLED can be a bottom-emitting OLED. Preferably, an OLED is a top-emitting OLED.

[0039] The top-emitting OLED comprises successively from a substrate 110 (Figure IA and Figure IB): a first electrode (or lower electrode) 121, optionally a buffer layer (not shown), the hole injection layer 131 (P-type layer) covering the first electrode 121, - a layer of hole transport 141, - an electroluminescent layer 150 (or emissive layer), emitting at a first wavelength, - an electron transport layer 142, - an electron injection layer 132 (N-type shell), - a second electrode (or upper electrode) 122.

[0040] Such a structure is a top-emitting structure. The invention can also be applied to a so-called inverted top-emitting structure, in which case the position of the electron injection / transport layers and the hole injection / transport layers are reversed.

[0041] At least one electron injection layer 132 or hole injection layer 131 is a layer made of a first inorganic perovskite material. The other of the electron injection layer 132 or hole injection layer 131 may be a layer made of a second inorganic perovskite material. Such layers exhibit good performance and very good long-term stability.

[0042] The first inorganic perovskite material and the second inorganic perovskite material are chosen so as to allow an electrical function that allows electrons or holes to pass through.

[0043] The first inorganic perovskite material and the second inorganic perovskite material are, for example, CsPbCl3. These may be perovskite materials doped with elements, particularly metallic elements, playing the role of role of load carriers. For example, their doping is greater than 10 16 cm -3 .

[0044] According to a particular embodiment, when the electron injection layer 132 is made of perovskite material, it can perform both the role of injection and spectral conversion.

[0045] The thickness of the first inorganic perovskite material layer and / or the thickness of the second inorganic perovskite material layer are, for example, less than 20 pm, and in particular between 50 nm and 2 pm, preferably between 100 nm and 1 pm.

[0046] If one of the injection layers is not made of perovskite material, it can be made of organic or polymer material, doped or undoped, semiconductor or conductive.

[0047] The electron or hole injection function can be handled entirely by the first perovskite material layer or the second perovskite material layer (Figure IA).

[0048] Alternatively, perovskite layers can be used in combination with additional layers to form a bilayer. The materials of the additional layers differ from those of the perovskite layers. These additional layers are made of a material that provides an electrical function, allowing the passage of electrons or holes. For example, the additional layers are oxide layers, such as tungsten oxide (WO3).

[0049] For example, Figure IB depicts an electron injection layer 132 in a first inorganic perovskite material used in association with an additional first layer 134. The hole injection layer 131 in a a second inorganic perovskite material is used in association with a second additional layer 133.

[0050] The additional layers are preferably arranged between the injection layers 131, 132 and the organic stack or between the injection layers 131, 132 and the electrodes 121, 122.

[0051] In the various figures attached, the transport and injection functions (of holes or electrons) are carried out by distinct layers.

[0052] According to an alternative embodiment, not shown, the hole transport or electron transport function can be performed by the hole injection or electron injection layer. The OLED then comprises the following stack: a hole injection layer, an electroluminescent layer properly speaking, emitting at a first wavelength, and an electron injection layer.

[0053] According to a particular embodiment not shown, the device may also include an electron carrier blocking layer on the side of the hole injection / transport layers and / or a hole carrier blocking layer on the side of the electron injection / transport layers.

[0054] Substrate 110, for example, is a glass or silicon substrate. For instance, it is a TFT substrate. Specifically, a glass TFT substrate would be chosen.

[0055] The first electrodes 121 are, for example, made of indium tin oxide (ITO), Al, or an AlCu or TiN alloy. These first electrodes 121 can be opaque and can be relatively thick (several hundred nanometers, or even a few micrometers). The first electrodes are anodes.

[0056] The buffer layer is, for example, made of TiN. It can have a thickness of around 10 nm.

[0057] The electroluminescent layer 150, for example, exhibits emission centered at a wavelength of 550 nm. It is an organic layer, for example a doped or undoped polymer material.

[0058] The hole transport layer (HTL) 141 and the electron transport layer (ETL) 142 are made of an organic material, such as a polymer, doped or undoped, semiconductor or conductive. These materials are known in themselves and will not be described in detail here.

[0059] The electroluminescent layer 150 and the electron transport layers 142 or hole transport layers 141 form an organic stack.

[0060] The second electrode 122 can be metallic. For example, the second electrode 122 is made of Ag and has a thickness of, for example, 10 nm. The chosen thickness is sufficiently small for the electrode 122 to be practically transparent.

[0061] Preferably, the electron injection layer 132 is made of perovskite material. This allows for a wider choice of materials for the upper electrode 122. It can, for example, be made of a transparent conductive oxide, such as ITO.

[0062] The second electrode 122 is the cathode.

[0063] Such OLEDs are particularly interesting for the manufacture of optoelectronic devices, such as OLED displays, especially direct-view OLED displays, which can range in size from that of a watch face to that of a television screen, or such as OLED microdisplays. In the first case, the support / control circuit board is a glass board with TFTs. The second type uses a silicon CMOS circuit. Color microdisplays consist of pixels made up of blue, green, and red sub-pixels (RGB pixels). For brevity, these sub-pixels will be referred to simply as pixels throughout this description. The pixels form the emitting part of the system. Each pixel can contain an OLED100 as described previously.

[0064] The optoelectronic device co-integrates organic pixels adapted to emit light in different wavelength ranges: for example, blue pixels emitting blue light (i.e., wavelength between 450 and 490 nm), green pixels emitting green light (i.e., wavelength between 490 and 570 nm) and red pixels emitting red light (i.e., wavelength between 600 and 700 nm).

[0065] Figures 2 to 4 represent 1000 emission optoelectronic devices comprising three pixels B, R and G. In practice, the display device may include a plurality of identical or similar B pixels, a plurality of identical or similar R pixels, and a plurality of identical or similar G pixels, the pixels of each type B, R and G being able to be regularly distributed over substantially the entire surface of the device, for example according to a matrix arrangement.

[0066] The device is a top emission device.

[0067] The 1000 device shown in the figures is a monolithic device. However, the individual B, R, and G pixels could be manufactured individually.

[0068] More specifically, the 1000 device, for example, an OLED microscreen or an OLED screen, comprising OLEDs as described previously. More specifically, device 1000 comprises successively (figures 2, 3 and 4): - a substrate 110, - the first 121 structured electrodes (or lower electrodes) arranged on the substrate, delimiting blue pixels, red pixels and green pixels, - possibly, a buffer layer (not shown), - a layer of hole injection 131 covering the first electrodes 121, - a layer of hole transport 141, - a 150 emissive layer, emitting at a first wavelength, - an electron transport layer 142, - an electron injection layer 132, - a spectral conversion element 161 arranged directly above one of the first electrodes delimiting the red pixel, absorbing at the first wavelength and emitting at a second wavelength greater than the first wavelength and an additional spectral conversion element 162 arranged directly above one of the first electrodes delimiting the green pixel, absorbing at the first wavelength and emitting at a third wavelength greater than the first wavelength.

[0069] The 1000 device also includes: - a second electrode (or upper electrode) 122 common to the three pixels B, R, G, and - an encapsulation layer 170.

[0070] According to a first embodiment, for example represented in Figure 2, the device 1000 comprises, starting from the electron injection layer 132: - the second electrode 122, - the encapsulation layer 170, - spectral conversion elements 161, 162.

[0071] According to a second embodiment, for example shown in Figure 3, the device 1000 includes from the electron injection layer 132: - spectral conversion elements 161, 162, - the second electrode 122, - the encapsulation layer 170.

[0072] As previously stated, at least one of the hole injection layer 132 or hole injection layer 131 of the OLED is a layer made of a first inorganic perovskite material, and possibly the other of the electron injection layer 132 or hole injection layer 131 is a layer made of a second inorganic perovskite material. One or both of the injection layers 131, 132, or both injection layers 131 and 132, can be used in the form of a bilayer as previously described.

[0073] As previously stated, when the electron injection layer 132 is made of perovskite material, it can perform both the role of injection and spectral conversion.

[0074] Preferably, at least the electron injection layer 132 is the first layer made of inorganic perovskite material. This allows for a wider range of deposition techniques for forming the top electrode 122 and / or the spectral conversion elements 161, 162, as well as a wider range of materials. The perovskite material layer protects the underlying organic material layers during the formation of the overlying layers.

[0075] Preferably, the spectral conversion element 161 is in another inorganic perovskite material (or a third inorganic perovskite material) and / or the additional spectral conversion element 162 is in a material additional inorganic perovskite (or fourth inorganic perovskite material).

[0076] The inorganic perovskite material of spectral conversion element 161 is different from the inorganic perovskite material of electron injection layer 132.

[0077] For example, spectral conversion element 161, which converts blue light to red light, is made of CsPbI2Br. Spectral conversion element 162, which converts blue light to green light, is made of CsPbBr3.

[0078] The use of 161, 162 perovskite converters allows for thinner converters (typically less than 500 nm thick), which are more stable and have a longer lifespan compared to using QD. This improves efficiency, results in more intense light at different wavelengths, and enables color saturation.

[0079] Alternatively, one or both spectral conversion elements 161, 162 may be in a composite material comprising dispersed quantum dots (QDs), for example, in a resin.

[0080] Spectral conversion elements 161, 162 locally cover the sub-acent layer. They can be separated from each other by an element such as a refractive index liquid or by a gap.

[0081] The resulting 1000 device exhibits better stability.

[0082] According to a particular embodiment, for example shown in Figure 4, color filters 180 cover the spectral conversion elements 161, 162. Color filters are optical elements that transmit certain wavelengths while absorbing other wavelengths. For example, a red filter lets red light through and filters or blocks light of other colors (blue and green, for example). For the red pixel, a red filter is placed on the spectral conversion element 161, and for the green pixel, a green filter is placed on the additional spectral conversion element 162.

[0083] 180 color filters are preferably made of an organic material.

[0084] The encapsulation layer 170 is made of an insulating material, for example, silica or silicon nitride. It can also be made of alumina or titanium oxide. Its thickness can range from 5 to 25 nm, preferably between 5 and 10 nm. A multilayer encapsulation structure is also possible. For example, a SiCt / TiCy multilayer is possible.

[0085] The device also includes a control circuit (not shown) allowing individual control of the OLEDs to display images.

[0086] We will now describe in more detail the manufacturing process of a device 1000 as previously described by referring to figures 5A to 5F, 6A and 6B as well as 7A and 7B.

[0087] The manufacturing process includes at least the following steps: - to form first electrodes 121 on a substrate 110, each first electrode 12 delimiting a pixel (figure 5A), - possibly deposit a buffer layer, deposit a hole injection layer 131, so as to cover the substrate 110 and the first electrodes 121 (figure 5B), form an electroluminescent organic stack by successively depositing a hole transport layer 141, an electroluminescent layer 150 and an electron transport layer 142 (figure 5C), - deposit an electron injection layer 132 (figure 5D).

[0088] The OLEDs (apart from the upper electrode 122) are thus formed on the substrate 110.

[0089] According to a first embodiment shown in Figures 6A and 6B, the process further comprises the following subsequent steps: - deposit a conductive layer by PLD to form the second electrode 122, then deposit an encapsulation layer 170 (figure 6A), - to form spectral conversion elements 161, 162 in inorganic perovskite material opposite some of the first electrodes, preferably by PLD (figure 6B), - possibly place separation elements 190 between the conversion elements 161, 162, - preferably, place color filters 180 on spectral conversion elements 161, 162.

[0090] According to a second embodiment shown in Figures 7A and 7B, the process further comprises the following subsequent steps: - to form spectral conversion elements 161, 162 in inorganic perovskite material opposite some of the first electrodes, by PLD (figure 7A), - preferably, apply color filters 180 to spectral conversion elements 161, 162, - possibly place separation elements 190 between the conversion elements 161, 162, - deposit a conductive layer, preferably by PLD, to form the upper electrode 122 and then deposit an encapsulation layer 170 (figure 7B).

[0091] In both of these embodiments, the injection layer(s) 131, 132 are preferably deposited by Pulsed laser ablation (PLD for 'pulsed laser deposition'). PLD is a physical vapor deposition (PVD) technique that involves forming a plasma plume from a target material using a pulsed laser. The plasma plume has a composition very close to that of the target (stoichiometric transfer of species). Upon contacting the structure onto which the perovskite layer is to be deposited, the plume nucleates the layer under vacuum and in a controlled atmosphere. The structure can then be moved within the deposition chamber to ensure uniform coating.

[0092] If one of the injection layers 131, 132 is made of an organic material, it can be deposited by other techniques, including by liquid method.

[0093] The first electrodes 121 are formed by applying a mask with openings corresponding to the positions of the electrodes 121 to the substrate 110, and then depositing the electrodes through this mask. They can be deposited, for example, by physical vapor deposition (PVD). They can also be deposited by a conventional chemical vapor deposition (CVD) technique. It is also possible to deposit a layer of metal and then structure it by lithography / etching to form the first electrodes 121.

[0094] The buffer layer can be deposited for example by PLD, PVD, PECVD (“Plasma-Enhanced Chemical Vapor Deposition”) or ALD (“Atomic Layer Deposition”).

[0095] The organic stack is then deposited. It can be formed by PVD or liquid phase deposition.

[0096] The second electrode 122 can be deposited by PLD onto the perovskite electron injection layer 132. PLD deposition allows for low-temperature deposition. (typically at temperatures ranging from room temperature (20-25°C) to 70-80°C) good quality layers. The electrode deposited by PLD can be made of ITO. The resulting ITO electrode is both transparent and conductive. Such properties are achieved at low temperatures, whereas for sputter-deposited electrodes, an additional annealing step would be necessary, which would be a major drawback for OLEDs.

[0097] The encapsulation layer 170 can be deposited by ALD or PVD. For example, a silicon oxide layer can be deposited by PVD. A TiCy layer can be formed by atomic layer deposition (ALD). An alumina layer can be deposited by ALD.

[0098] The conversion elements 161, 162 can be deposited by PLD when they are made of perovskite material. When they are made of hybrid (or composite) material, they can be deposited by liquid deposition, evaporation, PVD, CVD or by a hybrid process.

[0099] With such a process, the device is simpler to manufacture.

[0100] The different characteristics presented for OLED are found for the device and the different characteristics for the manufacturing process are found for the device or for OLED and vice versa.

[0101] Various embodiments and variations have been described. A person skilled in the art will understand that some features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0102] Finally, the practical implementation of the described embodiments and variants is within the reach of the person in the trade based on the functional specifications given above.

Claims

22 DEMANDS 1. Organic light-emitting diode (100) comprising successively: - a first electrode (121), - a hole injection layer (131), - an emitting layer (150), emitting at a first wavelength, - an electron injection layer (132) made of inorganic perovskite material, - a spectral conversion element (161) in inorganic perovskite material, a second electrode (122) in conductive transparent oxide.

2. Diode according to claim 1, wherein the hole injection layer (131) is a layer of inorganic perovskite material.

3. Diode according to any one of the preceding claims, wherein a substrate (110) is successively coated by: - the first electrode (121), - the hole injection layer (131), - a hole transport layer (141), - the emissive layer (150), - an electron transport layer (142), the electron injection layer (132), in inorganic perovskite material, the spectral conversion element (161) in inorganic perovskite material, the second electrode (122) in transparent conductive oxide, for example in indium tin oxide.

4. Diode according to any one of the preceding claims, wherein a first additional layer (133), by an example in oxide, in particular in tungsten oxide, is in contact with the electron injection layer (132) in inorganic perovskite material so as to form a bilayer and / or in which a second additional layer (134), for example in oxide, in particular in tungsten oxide, is in contact with the hole injection layer (131) so as to form another bilayer.

5. Diode according to any one of the preceding claims, wherein at least one of the inorganic perovskite materials is a halogenated perovskite material.

6. An optoelectronic device (1000) with organic light-emitting diodes, for example, an OLED microdisplay or an OLED display, comprising successively: - a substrate (110), - first structured electrodes (121) arranged on the substrate (110), delimiting blue pixels, red pixels and green pixels, a hole injection layer (131) covering the first electrodes (121), an emissive layer (150), emitting at a first wavelength, - an electron injection layer (132), made of inorganic perovskite material, - a spectral conversion element (161) made of inorganic perovskite material, positioned directly above one of the first electrodes (121) defining the red pixel, absorbing at the first wavelength and emitting at a second wavelength longer than the first wavelength, and an additional spectral conversion element (162) positioned directly above one of the first electrodes (121) defining the green pixel, absorbing at the first wavelength and emitting at a third wavelength greater than the first wavelength, a second electrode (122) of transparent conductive oxide, for example in indium tin oxide, covering the spectral conversion element (161) and the additional spectral conversion element (162).

7. Device according to the preceding claim, wherein the hole injection layer (131) is a layer of inorganic perovskite material.

8. Device according to claim 6 or 7, wherein the additional spectral conversion element (162) is made of inorganic perovskite material.

9. Method of manufacturing an organic light-emitting diode (100) as defined in any one of claims 1 to 5, the method comprising a step in which the electron injection layer (132) is formed by depositing an inorganic perovskite material by PLD.

10. Method according to claim 9, wherein the hole injection layer (131) is formed by depositing an inorganic perovskite material, preferably by PLD.

11. A method according to any one of claims 9 and 10, wherein the upper electrode (122) of a transparent conductive oxide, for example in indium tin oxide, is deposited by PLD.

12. A method for manufacturing an optoelectronic device (1000), comprising implementing the method for manufacturing an OLED according to any one of claims 9 to 11 for manufacturing several OLEDs on a substrate (110), and wherein the conversion elements 25 spectral (161) in inorganic perovskite material are deposited by PLD.

Images