METHOD FOR MANUFACTURING A µLED CHIP ARCHITECTURE BASED ON NANOSTRUCTURED PEROWSKIT CONVERTER MATERIALS

Abstract

Method for manufacturing an optoelectronic semiconductor device, comprising: - Providing an optoelectronic semiconductor chip (1) comprising: at least one light-emitting layer (4), at least one cavity (3), and - Inserting at least one pre-stage of a conversion element into the at least one cavity, wherein the at least one conversion element (6, 6') comprises a perovskite-based ABX3 or A2BB'X6 structure; and The introduction of a preliminary stage of at least one conversion element includes the following steps: - Introducing a solution of AX into at least one cavity (3), - Introducing a solution of BX2 in the case of an ABX3 structure or BX and B'X3 in the case of an A2BB'X6 structure into the at least one cavity (3), wherein A is at least one cation selected from the group consisting of methylammonium, formamidinium, K + , Rb +and Cs + is; X selected from the group consisting of F - , Cl - , Br - and I - is; B is a cation selected from the group consisting of Pb 2+ , Sn 2+ or Ge 2+ is; in the case of an A2BB'X6 structure, B and B' can be from Ag + or Bi + and Bi 3+ be selected.

Description

[0001] A method for manufacturing an optoelectronic semiconductor device, an optoelectronic semiconductor device, and a use of an optoelectronic semiconductor device are described.

[0002] Perovskite-based materials for generating green and red light are based on the structural formula ABX3 or A2BB'X6, where an inorganic cation (usually cesium or potassium, or an organic molecule such as methylammonium or formamidinium) occupies position A. For optical applications in the visible and near-infrared range, lead or tin are used at position B, or silver and bismuth, or bismuth alone, at positions B and B', and halides such as chlorides, bromides, or iodides are used as the anionic component at position X.

[0003] To adjust the absorption and emission spectrum of the perovskite converter material in the green / red spectral range, the anionic component is varied between chlorides (blue / green spectral range), bromides (green spectral range), iodides (red / infrared spectral range) or mixtures of these.

[0004] US patent 2017 / 0155020A1 discloses a wavelength-converting material and an application thereof. The wavelength-converting material comprises a completely inorganic perovskite quantum dot with the chemical formula CsPb(Cl₂). a Br 1-a-b I b )3, where 0≦a≦1, 0≦b≦1. US 2017 / 0268128 A1 discloses a system and method for producing a perovskite layer, wherein the system comprises a housing for use as a CVD furnace with a first and a second section, each coupled to a first and a second temperature control unit.

[0005] One problem to be solved by the present invention is to provide an optoelectronic semiconductor device, comprising, for example, several microLED chips, which has a microstructure and emits white light with a widely adjustable color temperature. In this application, a microLED chip is understood to be an LED chip architecture whose dimensions do not exceed an edge length of 150 µm. A further problem to be solved is to provide a method for fabricating an optoelectronic semiconductor device, as well as the use of such an optoelectronic semiconductor device.

[0006] These tasks are solved, among other things, by the subject matter of the independent patent claim. Advantageous further developments and embodiments are the subject matter of the dependent patent claims.

[0007] The present invention relates to a method for manufacturing an optoelectronic semiconductor device, comprising: - Providing an optoelectronic semiconductor chip, including: at least one light-emitting layer, at least one cavity, and - Introducing at least one precursor of a conversion element, wherein the at least one conversion element comprises a perovskite-based ABX3 or A2BB'X6 structure.

[0008] For the purposes of this invention, an optoelectronic semiconductor component is understood to be, for example, an LED (light emitting diode) component, in particular a component with at least one µLED chip.

[0009] In the context of the present invention, an optoelectronic semiconductor chip is understood to be a separately handleable and electrically contactable element. A semiconductor chip is produced, in particular, by singulation from a wafer array.

[0010] According to the present invention, the optoelectronic semiconductor chip comprises at least one light-emitting layer. This layer can, for example, be indium-doped gallium nitride.

[0011] The optoelectronic semiconductor chip further comprises at least one cavity. The cavity can also be referred to as a recess or cavity. The cavity preferably comprises the light-emitting layer as the bottom and one or more partitions as side walls. Particularly preferably, a cavity within the scope of the invention does not have a cover layer by which it would be completely enclosed, but is to be understood as an open structure.

[0012] In one embodiment, the partition(s) abut the at least one light-emitting layer and form a 90° angle with it. In an alternative embodiment, the partitions can be arranged at an approximately 90° angle on the light-emitting layer. Another embodiment comprises an arrangement in which the partitions are each positioned at an angle of 120° to one another.

[0013] The partitions are preferably reflective. The material of the reflective partitions can be epoxy or silicone, which is provided with reflective particles such as titanium dioxide, and / or metal particles such as silver, aluminum, or gold, and / or barium titanium dioxide particles such as BaTiO3, and / or yttrium boron oxide particles such as YBO3, and / or alkaline earth metal carbon oxide particles such as CaCO3 or MgCO3, and / or ZnS and / or ZnO and / or ZrO2 and / or BaSO4. Furthermore, the partitions can comprise at least one of the following materials: Ni, Al, Au, Si, Ag.

[0014] The partitions can also be absorbent, especially highly absorbent, either additionally or alternatively.

[0015] The material used for the absorbing partitions can be carbon-based materials.

[0016] The partitions can have a length of approximately 3 µm to approximately 30 µm, preferably from approximately 4 µm to approximately 15 µm, and particularly preferably from approximately 5 µm to approximately 10 µm.

[0017] The partitions can have a height of approximately 0.5 µm to approximately 5 µm, preferably from 1 µm to approximately 2 µm.

[0018] The partition walls can have a thickness of approximately 1 µm to approximately 10 µm, preferably from 1 µm to approximately 2 µm.

[0019] If more than one cavity is present, the partitions preferably create an optical separation of the individual cavities.

[0020] At least one precursor of a conversion element is placed into the at least one cavity, wherein the at least one conversion element comprises a perovskite-based ABX3 or A2BB'X6 structure.

[0021] The dimensions of the at least one cavity depend, among other things, on the dimensions of the partition walls. Preferably, a cavity has a base area of ​​at least 1 µm × 1 µm.

[0022] The partitions can also form a kind of grid structure, which defines the cavity(s). A grid structure requires more than two partitions. This can also increase the number of cavities.

[0023] The partitions are preferably designed to prevent the flow of liquid conversion material into the cavities formed by the partitions. The partitions thus act as a kind of barrier.

[0024] The base area of ​​the optoelectronic semiconductor chip, which is formed by the multiple cavities and the lattice structure, is particularly large in the range of approximately 1 mm². 2 up to approximately 5 mm 2 , preferably in the range of approximately 1 mm 2up to approximately 3 mm 2 , especially preferably of approximately 1 mm 2 up to approximately 2 mm 2 .

[0025] The partitions, for example for a grid structure, can be produced using micro-printing techniques, such as lithography, or by electroplating methods. For example, in one embodiment, a structured photoresist mask can be used to apply the partitions. The photoresist mask can be designed such that it has grooves in the area where the partitions are to be formed. The partitions then form within these grooves.

[0026] In one embodiment, the partitions are formed from a photoresist, which can be produced, for example, using a lithography process.

[0027] In one embodiment, the at least one partition wall can also be applied electroplated.

[0028] In another embodiment, the at least one partition can also be produced using a deposited polydimethylsiloxane lattice structure. To increase the reflectivity at the partitions, silver platelets, for example, can be added to the polydimethylsiloxane as an additive during curing. The cured polydimethylsiloxane template can then be applied to a light-emitting layer.

[0029] In another embodiment, the partitions can be inserted into the spaces between already placed blue-light-emitting chips. Thus, the footprint of the optoelectronic semiconductor chip corresponds to the footprint of the cavity and allows the realization of a µLED chip-based LED architecture that emits red, green, and blue light via full conversion when two of the three cavities are filled with green or red perovskite converter material, respectively.

[0030] The at least one conversion element has a perovskite-based ABX3 or A2BB'X6 structure. Examples of perovskite-based ABX3 or A2BB'X6 structures are: (K 0,2 Cs 0,8 )PbBr3, CsPbCl3, CsPbBr3 CsPbl3, CsSnCl3, CsSnBr3 CSSnl3, Cs2BiAgCl6, Cs2BiAgBr6 or Cs2BiAgl6.

[0031] In one embodiment of the present invention, in the perovskite-based ABX3 or A2BB'X6 structure, the variables A generally represent at least one cation selected from the group consisting of methylammonium, formamidinium, K + , Rb + and Cs + , X for an anion selected from the group consisting of F - , Cl - , Br - and I - and B for a cation selected from the group consisting of Pb 2+ , Sn 2+ , Ge 2+ In the structural formula A2BB'X6, positions B and B' can each be represented by Ag, for example. + and Bi 3+ or Bi +and Bi 3+ be occupied.

[0032] In one embodiment according to the present invention, the introduction of a precursor stage of the at least one conversion element comprises the steps: - Introducing a solution of AX into at least one cavity, - Introducing a solution comprising BX2 in the case of an ABX3 structure or BX and B'X3 in the case of an A2BB'X6 structure into the at least one cavity, wherein A is at least one cation selected from the group consisting of methylammonium, formamidinium, K + , Rb + and Cs + is; X selected from the group consisting of F - , Cl - , Br - and I - is; B is a cation selected from the group consisting of Pb 2+ , Sn 2+ or Ge 2+ is.

[0033] If the step of introducing a solution of BX and B'X3 into the at least one cavity is present, then B Ag is preferably +or Bi + and B' Bi 3+ In such an embodiment, a solution of BX can first be prepared and then combined with a solution of B'X3.

[0034] A process comprising such a step can also be referred to as an “in situ” process for the fabrication of a perovskite-based ABX3 or A2BB'X6 structure.

[0035] The introduction of a solution of AX into the at least one cavity can be carried out using a micropipette. For example, a solution of AX in an organic solvent, preferably an aprotic solvent such as dimethylformamide or dimethyl sulfoxide, is prepared. The AX is introduced into the cavity from a preferably saturated solution.

[0036] The introduction of a solution of BX2 or BX and B'X3 into the at least one cavity can be carried out using a micropipette. For example, a solution of BX2 or BX and B'X3 in an organic solvent, preferably an aprotic solvent such as dimethylformamide or dimethyl sulfoxide, is prepared. Advantageously, the solution of BX2 or BX and B'X3 contains the same solvent as the solution of AX. BX2 or BX and B'X3 is introduced into the cavity from a preferably saturated solution.

[0037] In one embodiment, a solution of AX is first introduced into the cavity, followed by a solution of BX2 or BX and B'X3.

[0038] In another embodiment, a solution of BX2 or BX and B'X3 is first introduced into the cavity, followed by a solution of AX.

[0039] Preferably, a quantity of a solution of AX and a quantity of a solution of BX2 or BX and B'X3 are introduced such that the cavity is filled in such a way that no solution can escape from the cavity. In one embodiment, the at least one cavity is filled to a maximum of 90%, preferably 80%, more preferably to a maximum of 70%. In the case of multiple cavities, the cavities can be filled with the same or different quantities.

[0040] In one embodiment, the stoichiometric ratio of AX to BX2 or BX and B'X3 is in the range of 1:1. Depending on the targeted emission wavelength of the conversion element, the stoichiometric ratio between AX and BX2 or BX and B'X3 is adjusted. For example, for red / orange emission from the converter, a stoichiometric ratio of approximately 0.9:1.1 is chosen for an ABX3 structure between CsBr and Pbl2.

[0041] In one embodiment, the stoichiometric ratio of AX to BX and B'X3 is in the range of 1:0.5:0.5. Depending on the target emission wavelength of the conversion element, the stoichiometric ratio between AX and BX2 or BX and B'X3 is adjusted. The combination of CsBr, AgBr, and BiBr3 in the stoichiometric ratio 1:0.5:0.5, for example, results in a red-luminescent CS2AgBiBr6 structure.

[0042] In another embodiment, the introduction of a precursor stage of the at least one conversion element comprises the step: - Introducing at least one additive into the at least one cavity, wherein the additive is selected from the group consisting of 2-benzylethylamine, 2-tert-butylethylamine and mixtures thereof.

[0043] The additive is selected to achieve an optimal crystal size for the ABX3 or A2BB'X6 structure. Crystal sizes of approximately 200 nm to approximately 5 µm are preferred.

[0044] The additives 2-benzylethylamine and 2-tert-butylethylamine are particularly preferred. Depending on their state of matter, the additives can be introduced in liquid or gaseous form.

[0045] Preferably, a quantity of additive is introduced so that the cavity is filled in such a way that no additive can escape from the cavity.

[0046] In another embodiment, nanostructuring of the ABX3 or A2BB'X6 structure can be achieved by applying a shaping matrix after deposition of both precursors. For this purpose, the structure is exposed to gaseous solvent before removal of the shaping matrix, and the nanostructured ABX3 or A2BB'X6 structure is generated by heating after removal of the matrix. For example, deposited CsBr and PbBr2 can be structured using a nanostructured polydimethylsiloxane (PDMS) matrix and exposure to CH3NH2 gas.

[0047] In another embodiment, the introduction of the preliminary stage of the at least one conversion element comprises the step: - Heating to a temperature in the range between 50°C and 200°C, preferably 100°C to 190°C, more preferably 150°C to 180°C.

[0048] Upon heating, the solvent evaporates, and the ABX3 or A2BB'X6 structure of the conversion element forms from the precursor. The ABX3 or A2BB'X6 structure typically forms through crystallization. This process can result in the formation of numerous small crystals, polycrystalline structures, or even single crystals.

[0049] The temperature is selected to achieve optimal crystal size for the ABX3 or A2BB'X6 structure. Crystal sizes of approximately 200 nm to approximately 5 µm are preferred.

[0050] Heating to a specific temperature can be carried out for a duration of 30 seconds to 10 minutes, preferably 2 minutes to 8 minutes, more preferably 4 minutes to 6 minutes.

[0051] The duration of the heating process can be chosen depending on factors such as the type of solvent, the amount of solvent and / or the temperature of the heating.

[0052] The introduction of the preliminary stage of at least one conversion element can also include the following step: - Introducing a suspension into the at least one cavity, wherein the suspension comprises at least one nanoparticle of the perovskite-based ABX3 structure.

[0053] This step is carried out in particular in an alternative embodiment to the “in situ” method for producing a perovskite-based ABX3 or A2BB'X6 structure.

[0054] For medium- to high-power applications, perovskite-based ABX3 or A2BB'X6 structures, fabricated using the described in-situ method, are used as converters. For low-power applications, solution-processable perovskite nanocrystals are particularly suitable.

[0055] In the context of the present invention, a suspension is understood to be a heterogeneous mixture of substances in which nanoparticles of the perovskite-based ABX3 structure are present in a solvent, preferably an organic solvent. Suitable solvents include, for example, toluene, aliphatic hydrocarbons such as hexane, and octane.

[0056] Preferably, a quantity of suspension is introduced such that the cavity is filled to the point where no suspension can escape from the cavity. In one embodiment, the at least one cavity is filled to a maximum of 90%, preferably to a maximum of 80%, more preferably to a maximum of 70%. If there are multiple cavities, the cavities can be filled with the same or different quantities.

[0057] The nanoparticles typically have a size between approximately 2 nm and approximately 20 nm, preferably between approximately 2 nm and approximately 10 nm.

[0058] In one embodiment, nanoparticles are selected from perovskite-based ABX3 structures from groups 1 (K, Rb, Cs) for A, 14 (Ge, Sn, Pb) for B, 17 (Cl, Br, I) for X, and small organic molecules such as methylammonium or formamidinium for A. Exemplary perovskite-based ABX3 structures of the nanoparticles are: (K 0,2 Cs 0,8)PbBr3, CsPbCl3, CsPbBr3 CsPbl3, CsSnCl3, CsSnBr3 CsSnI3, Cs2BiAgCl6, Cs2BiAgBr6 or CS2BiAgI6.

[0059] In one embodiment of the present invention, the variables A in the perovskite-based ABX3 structure of the nanoparticles generally represent at least one cation selected from the group consisting of methylammonium, formamidinium, K + , Rb + and Cs + , X for an anion selected from the group consisting of F - , Cl - , Br - and I - and B for at least one cation selected from the group consisting of Pb 2+ and Sn 2+ .

[0060] The nanoparticles of the perovskite-based ABX3 structure can be produced using common methods known in the prior art.

[0061] The formation of the conversion element from the suspension, comprising at least one nanoparticle of the perovskite-based ABX3 structure, can be carried out analogously to the in situ method described above, i.e., by heating to a specific temperature within a specific time. Typically, only the solvent is evaporated by heating. Depending on the solvent, lower temperatures can be used than in the in situ method. For example, temperatures in the range of 60°C to 100°C are conceivable.

[0062] The crystal size of the perovskites is determined by the synthetically produced nanoparticles and is usually between 2 nm and 25 nm. This allows for the fabrication of converter layers with a lateral extent of up to 0.5 µm. Such converter layers can also be processed from solution and therefore generally do not require complex pick-and-place methods.

[0063] In another embodiment, the method for manufacturing an optoelectronic semiconductor device further comprises the step: - Coating of at least one conversion element.

[0064] Perovskite-based materials can exhibit instability with respect to temperature, water, and, to some extent, light. Therefore, these materials can be particularly advantageously embedded in a matrix and / or coated.

[0065] A matrix can be selected from the group consisting of, for example, AlO x or SiO x .

[0066] The matrix can be applied using atomic layer deposition (ALD).

[0067] The coating of at least one conversion element can be selected from the group consisting of, for example, AlO. x or SiO x .

[0068] The coating of at least one conversion element can be done, for example, using ALD.

[0069] In an alternative embodiment, the coating can also be applied to the precursors of the at least one conversion element. This is particularly possible when using nanoparticle suspensions as precursors for conversion elements. These could potentially be protected from environmental influences / premature aging by core-shell architectures (which are applied prior to deposition). The synthesis of these core-shell nanoparticles is carried out using established methods known in the prior art.

[0070] The emission spectrum of perovskites can be methodically and extremely precisely tuned between approximately 450 nm and 850 nm by altering the elemental composition and / or quantum contamination effects. Combined with the aforementioned miniaturization potential, i.e., adjusting the crystal size of the perovskites to between approximately 200 nm and approximately 5 µm, the perceived color of a white light source can thus be quantitatively adjusted, for example, by equipping individually addressable microLED chips with different green- and red-emitting perovskites.

[0071] In one embodiment, the optoelectronic semiconductor chip comprises at least two cavities, preferably at least three cavities.

[0072] If multiple cavities are present, they can have the same or different base areas. In a preferred embodiment, they have the same base area. Base areas in the range of 1 µm are conceivable. 2 up to 900 µm 2 per cavity, preferably base areas in the range of 1 µm 2 up to 100 µm 2 per cavity, base areas in the range of 4 µm are particularly preferred. 2 up to 25 µm 2 per cavity.

[0073] In one embodiment, a cavity has a volume of approximately 25 µm³. 3 If multiple cavities are present, they can have the same or different volumes. In a preferred embodiment, they have the same volume. Volumes in the range of 1 µm are conceivable. 3 up to 900 µm 3 per cavity, preferably volumes in the range of 1 µm 3 up to 100 µm 3per cavity, volumes in the range of 4 µm are particularly preferred. 3 up to 25 µm 3 per cavity.

[0074] In an embodiment in which multiple cavities are present (for example, two or three cavities), the insertion of a precursor of the at least one conversion element comprises the following steps: - Introducing a solution of AX into the first cavity, - Introducing a solution of BX2 or BX and B'X3 into the first cavity, - Introducing a solution of AX into the second cavity, - Introducing a solution of BX2 or BX and B'X3 into the second cavity, wherein A is at least one cation selected from the group consisting of methylammonium, formamidinium, K + , Rb + and Cs + is; X selected from the group consisting of F - , Cl - , Br - and I - is; B is a cation selected from the group consisting of Pb 2+ , Sn2+ or Ge 2+ is.

[0075] If the step of introducing a solution of BX and B'X3 is present, then B and B' can each be, for example, Ag + and Bi 3+ or Bi + and Bi 3+ be.

[0076] In this embodiment, the solutions of AX, BX2 or BX and B'X3 are preferably selected such that the solutions of AX for the first cavity and the second cavity are different and / or the solutions of BX2 or BX and B'X3 for the first cavity and the second cavity are different.

[0077] If, for example, three or more cavities are present in such an embodiment, with three cavities being preferred, then preferably no solutions of AX and BX2 or BX and B'X3 are introduced into at least one cavity.

[0078] In another embodiment, the solutions AX, BX2, and BX and B'X3 of the first cavity are selected to form a precursor to a conversion element capable of converting blue light into red light. Examples include CsPbl3 and mixtures of CsPb13 and CsPbBr3. The solutions AX, BX2, and BX and B'X3 of the second cavity can be selected to form a precursor to a conversion element capable of converting blue light into green light. Examples include CsPbBr3 and mixtures of CsPbBr3 and CsPbCl3.

[0079] For example, an optoelectronic semiconductor component (for example, an LED, in particular comprising at least one µLED chip) can be manufactured that emits white light.

[0080] The embodiments described above also apply to embodiments with any number n cavities.

[0081] In one embodiment, n identical precursors of conversion elements can be placed in n cavities, so that each cavity can have the same conversion element.

[0082] In one embodiment, n different precursors of conversion elements can be introduced into n cavities, so that the n cavities can have different conversion elements.

[0083] In one embodiment, n-1 identical or different precursors of conversion elements can be introduced into n cavities, so that n-1 cavities can have identical or different conversion elements.

[0084] In one embodiment, nx identical or different precursors of conversion elements can be introduced into n cavities, such that nx cavities can have identical or different conversion elements, wherein x <n ist.

[0085] The introduction of the preliminary stage of at least one conversion element can also include the following step: - Introducing a first suspension into the first cavity, wherein the suspension comprises at least one nanoparticle of the perovskite-based ABX3 structure; - Introducing a second suspension into the second cavity, wherein the suspension comprises at least one nanoparticle of the perovskite-based ABX3 structure, wherein the nanoparticles of the first and second suspensions are preferably different.

[0086] If, for example, three or more cavities are present in such an embodiment, with three cavities being preferred, then preferably a first suspension is introduced into at least one first cavity and a second suspension into a second cavity.

[0087] If, for example, three or more cavities are present in such an embodiment, with three cavities being preferred, then preferably no suspension with nanoparticles of the perovskite-based ABX3 structure is introduced into at least one cavity.

[0088] The introduction of the preliminary stages of the conversion elements and the further steps of the process for manufacturing a conversion element can be carried out as described above.

[0089] Furthermore, an object comprises an optoelectronic semiconductor component: - comprising at least one optoelectronic semiconductor chip, at least one light-emitting layer, at least one cavity, - at least one conversion element, wherein the at least one conversion element comprises a perovskite-based ABX3 or A2BB'X6 structure.

[0090] For the purposes of this application, an optoelectronic semiconductor component is understood to be, for example, an LED (light emitting diode), in particular comprising at least one µLED chip.

[0091] For the purposes of this application, an optoelectronic semiconductor chip is understood to be a separately handleable and electrically contactable element. A semiconductor chip is produced, in particular, by singulation from a wafer composite. According to the present invention, the optoelectronic semiconductor chip comprises at least one light-emitting layer. This layer can, for example, be gallium nitride.

[0092] The optoelectronic semiconductor chip also includes at least one cavity, as described above.

[0093] The at least one conversion element has a perovskite-based ABX3 or A2BB'X6 structure, as described above. Examples of perovskite-based ABX3 or A2BB'X6 structures are: (K0,2Cs 0, 8)PbBr3, CsPbCl3, CsPbBr3 CsPbl3, CsSnCl3, CsSnBr3 CSSnI3, Cs2BiAgCl6, Cs2BiAgBr6 or CS2BiAgI6.

[0094] In a further embodiment, the optoelectronic semiconductor device comprises at least one coating. The coating can be selected from the group consisting of AlO₂. x and SiO x .

[0095] Alternatively, at least one conversion element can be embedded in a matrix.

[0096] A matrix can be selected from the group consisting of AlO x and SiO x .

[0097] The matrix can be applied using atomic layer deposition (ALD).

[0098] The coating of at least one conversion element can be done, for example, using ALD.

[0099] In another embodiment, the optoelectronic semiconductor device comprises at least two cavities, preferably at least three cavities. Depending on the size of the optoelectronic semiconductor device, any number of cavities can be present.

[0100] The sizes of the cavities are conceivable within the range described above.

[0101] Furthermore, the subject matter is an optoelectronic semiconductor device manufactured according to a method as described herein.

[0102] Another aspect is the use of an optoelectronic semiconductor component described herein in an optoelectronic display device. Examples of optoelectronic display devices include displays, projectors, flat panel displays (such as TVs or mobile devices), user interfaces, devices for displaying optical information, etc.

[0103] In one embodiment, an unspecified, nanostructured lattice structure, which is reflective and / or absorbing of the emitted light, is deposited onto a blue emitter. Green- and red-light-emitting perovskite converters are introduced from solution into the resulting wells or cavities. Within a series of three adjacent wells, one well is filled without converter material, one well with a green-light-emitting converter, and one well with a red-light-emitting converter. Bromide- and iodide-based precursor materials are used for the green- and red-light-emitting converters, respectively.

[0104] Further advantageous embodiments and developments result from the exemplary embodiments described below in conjunction with the figures. Figures Fig.1 Top view of an optoelectronic semiconductor chip with one cavity Fig. 2 Top view of a two-cavity optoelectronic semiconductor chip Fig. 3 Top view of a three-cavity optoelectronic semiconductor chip Fig. 4 Top view of a four-cavity optoelectronic semiconductor chip Fig. 5 Top view of an optoelectronic semiconductor chip with twelve cavities of different sizes Fig. 6 Side view of a three-cavity optoelectronic semiconductor chip Fig. 7 Side view of a five-cavity optoelectronic semiconductor chip

[0105] Fig.Figure 1 shows an optoelectronic semiconductor chip (1) comprising a partition (2) and a cavity (3). The partition can have a thickness of 2 µm, a length of 5 µm, and a height of 1 µm. In such an embodiment, the cavity has a base area of ​​25 µm². 2 The cavity may contain a conversion element (e.g., CsPbBr3).

[0106] Fig. Figure 2 shows an optoelectronic semiconductor chip (1) comprising a partition (2) and two cavities (3) A and B. The partition can have a thickness of 2 µm, a length of 5 µm, and a height of 1 µm. The partition between cavities (3) A and B can have the same thickness or a different thickness (e.g., 5 µm). In such an embodiment, each cavity has a base area of ​​25 µm². 2Cavities (3) A and B can be the same size or different sizes. Each cavity (3) can have a conversion element (e.g., CsPbBr3). In one embodiment, a cavity (e.g., cavity B) can also have a different conversion element (e.g., CsPbI3).

[0107] The following examples are conceivable: Nr. Cavity A Cavity B 1 In-situ PerowskitCsPb(Br, I)3 in 2-Phenoxyethylamin Matrixverkapselt mit AlO x In-situ perovskite CsPbBr3 in 2-phenoxyethylamine matrix encapsulated with AlO x 2 In-situ PerowskitCsPb(Br, I)3 in 2-Phenoxyethylamin Matrixverkapselt mit AlO x no conversion element 3 In-situ perovskite CsPbBr3 in 2-phenoxyethylamine matrix encapsulated with AlO x no conversion element 4 Perovskite nanoparticles based on CsPb(Br,1)3 encapsulated with AlO x Perovskite nanoparticles based on CsPbBr3 encapsulated with AlO x 5 Perovskite nanoparticles based on CsPb(Br,1)3 encapsulated with AlO x no conversion element 6 Perovskite nanoparticles based on CsPbBr3 encapsulated with AlO x no conversion element

[0108] Fig. Figure 3 shows an optoelectronic semiconductor chip (1) comprising a partition (2) and three cavities (3) A, B, and C. The partition can have a thickness of 2 µm, a length of 5 µm, and a height of 1 µm. The partitions between the cavities (3) A, B, and C can have the same thickness or different thicknesses (e.g., 5 µm). In such an embodiment, each cavity (3) has a base area of ​​25 µm². 2Cavities (3) A, B, and C can be the same size or different sizes. Each cavity (3) can contain a precursor of a conversion element (e.g., CsBr) or each a conversion element (e.g., CsPbBr3).

[0109] In one embodiment, one cavity has a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to red light (e.g., CsPb(Br,I)3), one cavity has a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to green light (e.g., CsPbBr3), and one cavity has no conversion element.

[0110] The following examples are conceivable: Nr. Cavity A Cavity B Cavity C 1 In-situ perovskite CsPb(Br, I)3 encapsulated in a 2-phenoxyethylamine matrix with AlO x In-situ perovskite CsPbBr3 encapsulated in a 2-phenoxyethylamine matrix with AlO x No conversion element 2 Perovskite nanoparticles based on CsPb(Br, I)3 encapsulated with AlO x PerowskitNanopartikelbasierend aufCsPbBr3 verkapseltmit AlO x No conversion element

[0111] Fig.Figure 4 shows an optoelectronic semiconductor chip (1) comprising a partition (2) and nine cavities (3). The partition can have a thickness of 2 µm, a length of 5 µm, and a height of 1 µm. The partitions between the cavities (3) can have the same thickness or different thicknesses (e.g., 5 µm). In such an embodiment, each cavity (3) has a base area of ​​25 µm². 2 The cavities (3) can be of the same size or of different sizes. Each cavity (3) can contain a precursor of a conversion element (e.g., CsBr) or each a conversion element (e.g., CsPbBr3).

[0112] In one embodiment, at least one cavity has a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to red light (e.g., CsPbI3), and at least one cavity has a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to green light (e.g., CsPbBr3), and at least one cavity does not have a conversion element.

[0113] Fig. Figure 5 shows an optoelectronic semiconductor chip (1) comprising a partition (2) and twelve cavities (3). The partition can have a thickness of 2 µm, a length of 5 µm, and a height of 1 µm. The partitions between the cavities (3) can have the same thickness or different thicknesses (e.g., 5 µm). In such an embodiment, each cavity (3) has a base area of ​​between 10 and 25 µm². 2 on. Fig.Figure 5 shows that the cavities (3) can be of different sizes. The cavities (3) can each contain a precursor of a conversion element (e.g., CsBr) or each contain a conversion element (e.g., CsPbBr3).

[0114] In one embodiment, at least one cavity has a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to red light (e.g., CsPbI3), and at least one cavity has a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to green light (e.g., CsPbBr3), and at least one cavity does not have a conversion element.

[0115] Fig.Figure 6 shows a side view of an optoelectronic semiconductor chip (1) having four partitions (2) and three cavities (3). The partitions can have a thickness of 2 µm, a length of 5 µm, and a height of 1 µm. The partitions between the cavities (3) can have the same thickness or different thicknesses (e.g., 5 µm). A light-emitting layer (4) is also shown, which can be indium-doped gallium nitride. Each cavity (3) can have a conversion element (6, 6') (e.g., CsPbBr3). In the embodiment shown, the conversion elements (6, 6') are coated with a layer (5) (e.g., AIO). x coated.

[0116] In one embodiment, a cavity (3) lacks a conversion element, allowing the blue light from the light-emitting layer to escape. A cavity (3) can have a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to red light (e.g., CsPbI3), and a cavity (3) can have a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to green light (e.g., CsPbCl3). The color of the light thus produced (particularly white light) can be adjusted by the type and amount of the perovskite-based structure and the size of the respective cavities.

[0117] Fig.Figure 7 shows a side view of an optoelectronic semiconductor chip (1) having six partitions (2) and five cavities (3). The partitions (2) can have a thickness of 2 µm, a length of 5 µm, and a width of 1 µm. The partitions (2) between the cavities (3) can have the same thickness or different thicknesses (e.g., 5 µm). A light-emitting layer (4) is also shown, which can be indium-doped gallium nitride. In this embodiment, the light-emitting layer is separated by the respective partitions (2) into individual compartments, which can be controlled separately. Each cavity (3) can have a conversion element (6, 6') (e.g., CsPbBr3). The conversion elements (6, 6') can be coated with a layer (5) (e.g., AIO). x ) be coated.

[0118] The separate controllability of the light-emitting layers (4) and the presence of the partitions (2) ensure that a controlled light-emitting layer (4) does not overexpose an adjacent light-emitting layer (4) that is not controlled. This significantly reduces crosstalk between adjacent light-emitting layers (4) through the partitions (2).

[0119] In one embodiment, two cavities (3) lack a conversion element, allowing the blue light from the light-emitting layer to escape. One cavity (3) can have a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to red light (e.g., CsPbI3), and two cavities (3) can have a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to green light (e.g., CsPbBr3). In another embodiment, one cavity (3) can have a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to green light (e.g., CsPbBr3), and two cavities (3) can have a perovskite-based ABX3 or A2BB'X6 structure that converts blue light to red light (e.g., CsPbI3).

[0120] The color of the light produced (especially white light) can be adjusted by the type of perovskite-based structure, the amount of perovskite-based structure and the size of the respective cavities.

[0121] Examples of the fabrication of perovskite-based ABX3 or A2BB'X6 structures: “In-situ generation of perovskite-based ABX3 or A2BB'X6 structures”: The precursor AX (e.g., cesium halide (CsCl, CsBr, or Csl), methylammonium halide (MA Cl, MA Br, or MA I), or formamidinium halide (FA Cl, FA Br, or FA I; each with a purity of 99.999%)) is used without further purification. The precursor BX2 (e.g., PbCl2, PbBr2, or PbI2, each with a purity ≥ 98%) is dried in a vacuum oven at 150°C for at least 12 hours before further use. Equimolar amounts of the precursors AX and BX2 are dissolved in a polar, aprotic solvent (e.g., dimethyl sulfoxide (DMSO) or dimethylformamide (DMF)) under constant stirring at 50°C in air (approximately 45% relative humidity) (final total concentration: 0.45 M). After cooling to room temperature, the solution is treated with methyl cyanide or Methanol is titrated. Saturation is indicated by a permanent, white precipitate. The saturated solution is sealed and stirred for 24 hours at 50°C.Afterwards, a strongly fluorescent precipitate is visible, along with other precipitated substances. The saturated solution can be stored for several months in the absence of light. Before deposition, the saturated precursor solution is filtered (PTFE, 0.2 µm pore size). “Synthesis of colloidal, perovskite nanoparticles”: The synthesis of CsPbX3 (X = Cl, Br, or I) nanoparticles follows standard hot injection methods. First, Cs oleate is prepared by drying Cs2CO3 (0.814 g) together with octadekene (ODE, 40 mL, 90%) and oleic acid (2.5 mL, 90%) for 1 h at 120°C under vacuum. The material combination is then heated to 150°C under a protective gas atmosphere to form Cs oleate. Simultaneously, ODE is heated to 100°C under a protective gas atmosphere. In a separate reaction vessel, ODE (5 mL) and PbX₂ (0.188 mmol, i.e., PbI₂ (0.087 g, 99.999%), PbBr₂ (0.069 g, 98%), or PbCl₂ (0.052 g, 99.999%)) are combined and stirred at 120°C for 1 h. Dried oleylamine (0.5 mL, OLA, 80–90%) and dried oleic acid (0.5 mL) are injected into the latter reaction vessel at 120°C under a protective gas atmosphere. After the lead salt has completely dissolved, the temperature of the solution is increased to 140–200°C. Lower temperatures are used for small nanoparticles, and higher temperatures for larger nanoparticles.The prepared cesium oleate solution (0.4 mL, 0.125 M in ODE) is rapidly injected into the lead salt solution. Five seconds later, the reaction vessel is cooled using an ice bath. In the case of CsPbCl3 particles, a higher reaction temperature of at least 150°C and an additional 1 mL of trioctylphosphine (TOP, 97%) are required to solubilize PbCl2. To purify the formed nanoparticles, the cooled reaction solution is centrifuged to separate remaining reactants and aggregated particles. For smaller nanoparticles synthesized at temperatures <160°C, centrifugation is performed at 0°C, and tert-BuOH (tBuOH, 99%) is added. After centrifugation, the supernatant is discarded, and the synthesized nanoparticles are dissolved in hexane or toluene.

[0122] A common approach to synthesizing hybrid nanoparticles (i.e., APbX3, A = organic cation, X = halide) is the so-called "ligand-assisted reprecipitation" (LARP) method (see, e.g., Sichert et al. NanoLett 2015, 15, 6521). This involves working in a polar, aprotic solvent capable of dissolving the inorganic, lead-containing and organic ammonium salts (i.e., PbX2 and MA X, respectively) (e.g., DMSO or DMF). This solution, containing both salts, is injected into a nonpolar ("bad") solvent containing coordinating ligands such as oleic acid or oleylamine. The latter stabilize the forming nanoparticles in solution. Purification of the nanoparticles is carried out as described above.

[0123] Following the deposition process of the precursors of the conversion elements, in the case of in-situ generated perovskites, the solid is formed at a maximum temperature of 180°C (within several minutes).

[0124] The embodiments according to the invention make it possible to produce microstructured white light emitters whose color temperature is widely adjustable, thus ideally avoiding the need for complex handling of individual chips.

[0125] Furthermore, the present invention enables the realization of RGB-capable microLED arrays with a minimal pitch (potentially around 5 µm) based on individually controllable, blue microLED matrices with a preferably pre-placed edge length of up to 1 µm. Due to the limited structuring capabilities of the perovskite converter materials (potentially grain sizes of a few nm), the size limit for the individual pixels is not their RGB capability, but rather the initial size of the blue-light-emitting, InGaN-based semiconductor chip and the precision of the pick-and-place process. To facilitate defect management, a 3x3 chip arrangement within the pitch is recommended. Reference symbol list 1 Optoelectronic semiconductor chip 2 partition wall 3 Cavity 4 light-emitting layers 5 coating 6, 6' Conversion element

Claims

[1] Method for manufacturing an optoelectronic semiconductor device, comprising: - Providing an optoelectronic semiconductor chip (1) comprising: at least one light-emitting layer (4), at least one cavity (3), and - Inserting at least one pre-stage of a conversion element into the at least one cavity, wherein the at least one conversion element (6, 6') comprises a perovskite-based ABX3 or A2BB'X6 structure; and The introduction of a preliminary stage of at least one conversion element includes the following steps: - Introducing a solution of AX into at least one cavity (3), - Introducing a solution of BX2 in the case of an ABX3 structure or BX and B'X3 in the case of an A2BB'X6 structure into the at least one cavity (3), wherein A is at least one cation selected from the group consisting of methylammonium, formamidinium, K + , Rb +and Cs + is; X selected from the group consisting of F - , Cl - , Br - and I - is; B is a cation selected from the group consisting of Pb 2+ , Sn 2+ or Ge 2+ is; in the case of an A2BB'X6 structure, B and B' can be from Ag + or Bi + and Bi 3+ be selected. [2] Method for manufacturing an optoelectronic semiconductor device according to claim 1, wherein the introduction of the precursor of the at least one conversion element comprises the step: - Heating the solutions of claim 2 to a temperature in the range between 50°C and 200°C, preferably 100°C to 190°C, more preferably 150°C to 180°C. [3] Method for producing an optoelectronic semiconductor device according to claim 2, wherein heating is carried out for a duration of 30 seconds to 10 minutes, preferably 2 minutes to 8 minutes, more preferably 4 minutes to 6 minutes. [4] Method for manufacturing an optoelectronic semiconductor device according to claim 1, wherein the introduction of the precursor of the at least one conversion element comprises the step: - Introducing a suspension into the at least one cavity (3) wherein the suspension comprises at least one nanoparticle of the perovskite-based ABX3 structure. [5] Method for manufacturing an optoelectronic semiconductor device according to any one of the preceding claims, further comprising the step of: - Coating of at least one conversion element (6, 6'). [6] Method for producing an optoelectronic semiconductor device according to any one of the preceding claims, wherein in the perovskite-based ABX3 or A2BB'X6 structure A at least one cation selected from the group consisting of methylammonium, formamidinium, K + , Rb + and Cs + is; X selected from the group consisting of F - , Cl - , Br - and I - ; in the case of an ABX3 structure, B is a cation selected from the group consisting of Pb 2+ , Sn 2+ and Ge 2+ ; in the case of an A2BB'X6 structure, B is selected from the group consisting of Bi + and Ag + and B' is Bi 3+ . [7] Method for manufacturing an optoelectronic semiconductor device according to any of the preceding claims, wherein the optoelectronic semiconductor chip (1) comprises at least two cavities (3).

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