WO2017158053A1

WO2017158053A1 - Method for producing a conversion element, conversion element, and optoelectronic component

Info

Publication number: WO2017158053A1
Application number: PCT/EP2017/056163
Authority: WO
Inventors: Georg DIRSCHERL; David O'brien
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2016-03-18
Filing date: 2017-03-15
Publication date: 2017-09-21
Also published as: DE102016105103A1

Abstract

The invention relates to a method for producing a conversion element (100), having the following steps: A) providing quantum dots (1), which are designed for the wavelength conversion of radiation and which have a surface coating having terminal C-C double bonds (11), B) providing a matrix material (2), which comprises a first component (21) and a second component (22), wherein the first component (21) has at least two Si-H groups, wherein the second component (22) has at least two terminal C-C double bonds, C) bonding the first component (21) to the terminal C-C double bond of the quantum dots (1) by means of hydrosilylation, wherein the bonding performed in step C) occurs thermally, wherein the temperature is at least 80 °C, D) bonding the second component (22) to the first component (21) by means of at least one terminal C-C double bond of the second component (22) after the first component (21) has been bonded in step C), E) polymerizing the functionalized quantum dots produced in step D) such that a network of quantum dots (1) is produced, which are bonded to the matrix material (2).

Description

description

Method for producing a conversion element,

Conversion element and optoelectronic component

The invention relates to a method for producing a conversion element. Furthermore, the invention relates to a

Conversion element. Furthermore, the invention relates to a

optoelectronic component.

Conversion elements often have conversion materials, for example quantum dots. The conversion materials convert the radiation emitted by a radiation source into radiation with an altered, for example longer, wavelength. The conversion materials are usually dispersed in a polymer-based matrix material based on acrylic. Thus, the conversion elements consist of conversion materials and matrix material, so one

two-phase system. These biphasic systems generally have poor miscibility. Furthermore, there may be possible phase separations and scattering at the

Interface between the conversion materials and the

Matrix material come. In addition, are polymer-based

Matrix materials usually permeable to moisture and / or oxygen and / or acidic gases from the environment.

Furthermore, polymer-based matrix materials have a low aging stability. In addition, a homogeneous and

controllable distribution of the conversion materials in the matrix material difficult to adjust. Therefore, such

Conversion elements usually for optoelectronic

Components, such as LEDs, only conditionally

used. US 2015/0054425 A1 describes nanocomposite compositions and their preparation. An object of the invention is to provide a method for

To provide a conversion element to provide a conversion element with improved properties

manufactures. In particular, a conversion element

which has high transparency and / or miscibility problems during manufacture. In addition, the conversion element is a high efficiency

exhibit. It is another object of the invention to provide a

Conversion element and / or to provide an optoelectronic device having improved properties.

These objects are achieved by a method for producing a conversion element according to independent claim 1. Advantageous embodiments and modifications of the invention are the subject of the dependent claims. Furthermore, these objects are achieved by a conversion element according to independent claim 12 and by an optoelectronic device according to independent claim 13.

In at least one embodiment, the method for producing a conversion element comprises the steps:

A) Provision of Quantum Dots for the

Wavelength conversion of radiation are established and have a surface coating with terminal C-C double bonds,

B) providing a matrix material comprising a first

Component and a second component, wherein the first component has at least two Si-H groups, wherein the second component has at least two terminal CC double bonds, C) attachment of the first component to the terminal CC double bond of the quantum dots by means of hydrosilylation, wherein in particular carried out in step C)

Polymerization or bonding takes place thermally, the temperature being at least 80 ° C.,

D) attaching the second component via at least one terminal C-C double bond of the second component to the first component, after the first component has been attached to the quantum dots in step C), and

E) polymerization of those produced in step D)

functionalized quantum dots, creating a network of quantum dots attached to the matrix material.

The polymerization in step E) takes place in particular free-radically with at least one thermal initiator or UV initiator, where at least one initiator has the following structural formula:

By using the initiator with the above

Structural formula, this can easily be mixed in step E) with the functionalized quantum dots and thus simplify the production. In accordance with at least one embodiment, the method comprises the step A) of providing quantum dots. The

Quantum dots are for wavelength conversion or

Wavelength conversion set up.

The wavelength-converting quantum dots are, in particular, a sensitive conversion material, ie a conversion material sensitive to oxygen, moisture and / or acidic gases. Preferably, the quantum dots are nanoparticles, that is

Particles with a size in the nanometer range with a

Particle diameter d5 _Q , for example, between at least 1 nm and at most 1000 nm. The quantum dots comprise a semiconductor core having wavelength-converting properties. In particular, the core of the quantum dots comprises or consists of an II / IV or III / V semiconductor.

For example, the quantum dots are selected from a group comprising InP, CdS, CdSe, InGaAs, GalnP and CuInSe2. The semiconductor core may be coated by one or more layers as a coating. The coating may be organic and / or inorganic. In other words, the semiconductor core may be completely or almost completely covered by further layers on its outer surface or surface.

The semiconductor core can be a single crystal or

polycrystalline agglomerate.

According to at least one embodiment, the

Quantum dots have an average diameter of 3 nm to 10 nm, more preferably from 3 nm to 5 nm. By varying the size of the quantum dots, the wavelength of the converting radiation can be specifically varied and adapted accordingly for respective applications. The quantum dots can be spherical or

be formed rod-shaped. A first encapsulating layer of a quantum dot is, for example, an inorganic material such as

For example, zinc sulfide, cadmium sulfide and / or

Cadmium selenide is formed and serves to generate the

Quantum dot potential. The first sheath layer and the semiconductor core may be of at least a second one

enveloping layer to be almost completely enclosed on the exposed surface. In particular, the first coating layer is an inorganic ligand shell, which in particular has an average diameter including the semiconductor core of 1 nm to 10 nm. The second cladding layer may be formed, for example, with an organic material such as cystamine or cysteine, and sometimes serves to improve the solubility of the quantum dots in, for example, a matrix material and / or a solvent. In this case, it is possible that due to the second covering layer a spatially uniform distribution of the quantum dots in a matrix material

is improved. The matrix material can be formed, for example, with at least one of the following substances: acrylate, silicone, hybrid material, such as Ormocer, for example

Ormoclear, polydimethylsiloxane (PDMS), polydiphenylsiloxane (PDPS), for example from PLT, Pacific Light

Technologies, or mixtures thereof. Acrylo-functionalized quantum dots, such as Ormoclear, can be obtained, for example, from Nanoco. When dispersing the quantum dots in an inorganic or organic matrix material often results in the problem that the matrix material is not very stable. It is also a transparent two-component mixture. Furthermore, the matrix material is permeable to moisture and environmental influences, for example acidic gases. In addition, an optimum distance between the individual quantum dots can not be set sufficiently sufficiently so that a quenching of the emitted radiation is increased. this leads to

Efficiency losses of the conversion element.

The quantum dots have a surface coating. The surface coating is particularly organic.

Preferably, the second covering layer forms the

Surface coating of the quantum dots with terminal double bonds. In other words, at the surface of the quantum dots chemical compounds are attached, which have a terminal, that is terminal, double bond (C = C). In accordance with at least one embodiment, the terminal double bond of at least one quantum dot is part of one

Vinyl residues, a Methacrylatrestes or Acrylatrestes.

In accordance with at least one embodiment, the method comprises a step B), providing a matrix material that comprises a first component and a second component, wherein the first component has at least two Si-H groups, in particular terminal Si-H groups, where the second component has at least two terminal CC double bonds. In other words, it becomes one

Matrix material provided, which has a first component, which is in particular a hardener, and a second component, which is in particular a resin. In accordance with at least one embodiment, the second one

Component a C-C double bond functional

Polydimethylsiloxane (PDMS), in particular a vinyl-functionalized polydimethylsiloxane. Alternatively, the second component is a C-C double bond-functionalized polydiphenylsiloxane (PDPS), especially a vinyl-functionalized polydiphenylsiloxane. Alternatively, the second component is a mixture of a vinyl-functionalized polydimethylsiloxane and a vinyl-functionalized polydiphenylsiloxane, ie a vinyl-functionalized polymethylphenylsiloxane.

According to at least one embodiment, the first one

Component of the matrix material is a silane, in particular a

Disilane, thus has two Si-H groups. In particular, the Si-H groups are terminal, ie terminally attached to the first component. In accordance with at least one embodiment of the method, the first component is attached to the terminal C-C double bond of the quantum dots. The connection takes place in particular by means of hydrosilylation. Hydrosilylation refers to the syn-selective anti-Markovnikov addition of a silane to a double bond. This creates a coupling of a

Silicon atom to a carbon atom.

In accordance with at least one embodiment of the method, this comprises a step D) of attaching the second component via at least one terminal C-C double bond to the first component after the first component has been attached in step C). In other words, here is one

successive connection of the matrix material to the quantum dots generated. First, the first component to the

Tied to quantum dots. After the connection of the first component to the quantum dots, the

Connection of the second component to the quantum dots. Thus, quantum dots can be incorporated in a matrix material, wherein the quantum dots are homogeneously integrated in the matrix material and have no agglomeration. This causes a high degree of transparency of the conversion element. In addition, there are no miscibility problems due to the binding of the quantum dots to the matrix material. In addition, it is a so-called single-phase system of matrix material with attached quantum dots, so no

Phase separation or scattering occurs at the interfaces. According to at least one embodiment of the method, this has a step E), polymerization of the functionalized quantum dots generated in step D), so that a

Network is generated from quantum dots, which at the

Matrix material are connected. Among other things, the matrix material is used to claim the quantum dots. This forms a network of quantum dots and matrix material. In particular, the network is a two-dimensional and / or three-dimensional network. Network is understood here and below to mean that the quantum dots form the so-called nodes of the network, and the matrix material the connecting lines between the quantum dots. In particular, the quantum dots and the matrix material are connected to one another via chemical bonds, in particular via covalent and / or coordinative bonds. The in step D)

attached second component can be coupled by hydrosilylation to the terminal Si-H groups of the loaded quantum dots. The polymerization of the quantum dots with each other to

Formation of the network can be thermal, anionic,

cationic and / or radical. In accordance with at least one embodiment, the connection performed in step C) takes place thermally. A

Activation energy is for tying the first one

Component to the terminal C-C double bond of

Quantum dots by hydrosilylation preferred. The

Temperature of the polymerization is at least 80 ° C,

at least 90 ° C, at least 100 ° C, at least 110 ° C at least 120 ° C or at least 150 ° C, for example 95 ° C. As a result, an optimal connection of the first component can be achieved with advantage.

In accordance with at least one embodiment, the polymerization carried out in step E), in particular the

final polymerization via hydrosilylation at a temperature between 100 ° C and 200 ° C, for example at 150 ° C.

In accordance with at least one embodiment, the polymerization carried out in step E) takes place radically. According to at least one embodiment is in the

radical polymerization using a thermal initiator or UV initiator.

In accordance with at least one embodiment, Lucrin-TPO-L is used as the initiator for the radical polymerization.

Lucrin-TPO-L is ethyl 2, 4, 6-trimethylbenzoylphenylphosphinate having the structural formula

In accordance with at least one embodiment, the second component connected in step D) is added in deficit. In this case and below, the term "deficit" means in particular that the second component has a weight fraction of from a few ppm to 0.1% by weight, based on the total proportion in the

Has conversion element. In accordance with at least one embodiment, the first component attached in step C) is added in excess.

Excess here and hereinafter means in particular that the first component has a weight fraction of 55% by weight to 95% by weight, based on the total proportion in the conversion element.

In at least one embodiment, the polymerization in step E) is a hydrosilylation.

According to at least one embodiment, the quantum dots are selected from a group consisting of indium phosphide (InP),

Cadmium sulfide (CdS), cadmium selenide (CdSe) and

Copper indium selenide (CuInSe2). Alternatively or additionally, the surface coating may be an organic coating having terminal C-C double bonds.

The inventors have recognized that by using the conversion elements described herein, a single-phase system can be provided which has no phase separation or scattering at the interfaces. In addition, the Quantum dots involved in the matrix material, so that the conversion element has a high transparency, a high

Homogeneity and has no agglomeration. The

Quantum dots are therefore readily miscible in the matrix material, so there are no miscibility problems between

For example, quantum dots and vinyl-containing resin such as PDMS result. In particular, the matrix material is on

Silicone base, so that the connection of the matrix material to the quantum dots has a high aging stability and the conversion element excellent for optoelectronic

Components, such as LEDs, can be used.

The invention further relates to a conversion element.

Preferably, the conversion element is produced by the method described above. All apply in connection with the process for the preparation of the

Conversion element made statements and definitions for the conversion element and vice versa.

According to at least one embodiment, this includes

Conversion element quantum dots. The quantum dots are designed for wavelength conversion of radiation. The

Quantum dots have a surface coating. The conversion element has a matrix material. Adjacent quantum dots are about this matrix material for

Spacing the quantum dots connected to each other, so that a network of quantum dots and matrix material is formed. The matrix material is formed from a first and second component. The first component has at least two Si-H groups, in particular terminal Si-H groups. The second component has at least two terminal C-C double bonds. In particular, the first one

Component to at least one terminal CC double bond the quantum dots by means of hydrosilylation and the second component via the terminal CC double bonds of the second component to the first component.

In particular, the attachment of the first component to the second component takes place by means of hydrosilylation.

The network of quantum dots (1) and matrix material can preferably be produced by means of a free radical polymerization with at least one thermal initiator or UV initiator, where at least one initiator has the following structural formula:

, The initiator or UV initiator may be present in the finished conversion element or removed again.

Furthermore, an optoelectronic component is specified. Preferably, this optoelectronic component has a semiconductor chip and a conversion element described above. The conversion element is obtainable in particular by the method described above. In this case, all apply in connection with the process for the preparation of

Conversion element and the conversion element made statements and definitions for the optoelectronic device and vice versa.

The optoelectronic component is preferably a light-emitting light-emitting diode, in short LED. The

Optoelectronic component is preferably to

set up to emit blue light or white light. Alternatively, the optoelectronic component can also emit other colors, for example red, orange, green, or radiation from the IR range or a laser. The

Optoelectronic component has at least one

Semiconductor chip on. The semiconductor chip can have a

Have semiconductor layer sequence. The

Semiconductor layer sequence of the semiconductor chip based

preferably on a III-V compound semiconductor material. The semiconductor material is preferably a

Nitride compound semiconductor material such as Al _n _In] __ _n _ _m Ga _m N, or a phosphide compound semiconductor material such as Al _n _In] __ _n _ _m Ga _m P, where in each case 0 ^ n 1, 0 ^ m 1 and n + m <1. May be the semiconductor material is Al _x _Ga] __ _x As well act with 0 ^ x ^ 1. Here, the

Semiconductor layer sequence dopants and additional

Have constituents. For the sake of simplicity, however, only the essential constituents of the crystal lattice of the semiconductor layer sequence, ie Al, As, Ga, In, N or P, are given, even if these can be partially replaced and / or supplemented by small amounts of further substances.

The semiconductor layer sequence includes an active layer with at least one pn junction and / or with one or more quantum well structures. In operation of the

Optoelectronic component or the semiconductor chip, an electromagnetic radiation is generated in the active layer. A wavelength or a wavelength maximum of the radiation is preferably in the ultraviolet and / or

visible and / or infrared spectral range, in particular at wavelengths between 420 nm and 800 nm inclusive, for example between 440 nm and 480 nm inclusive. The conversion element is arranged in particular in the beam path of the semiconductor chip. In particular, that covers

Conversion element, the radiation exit surface of the

Semiconductor chips directly. Alternatively, the conversion element is spaced from the radiation exit surface of the semiconductor chip.

Further advantages, advantageous embodiments and

Further developments of the invention will become apparent from the im

Described below in conjunction with the figures

Exemplary embodiments.

In the figures: FIGS. 1A to 1C each show quantum dots according to a

Embodiment, the Figure 2 C-C double bonds according to an embodiment, Figures 3A and 3B each have a conversion element according to an embodiment, Figures 4 and 5 are each a method for manufacturing

a conversion element according to a

Embodiment and Figures 6A to 6G each an optoelectronic

Component according to one embodiment. In the exemplary embodiments and figures, identical, identical or identically acting elements can each be provided with the same reference numerals. The illustrated elements and their proportions with each other are not to be considered as true to scale. Rather, individual elements, such as layers, components, components and areas for exaggerated representability and / or for better understanding can be exaggerated.

FIGS. 1A to 1C each show a schematic

Side view of a quantum dot according to a

Embodiment. The quantum dot 1 can, as shown in Figure 1A, a

Semiconductor core la include or consist of. Of the

Semiconductor core la may be formed, for example, as cadmium selenide, cadmium sulfide, indium phosphide and / or copper indium selenide.

FIG. 1B shows a quantum dot 1 which is next to the

Semiconductor core la has an enveloping first layer 1b. For example, the enveloping first layer 1b may be formed of zinc sulfide. The quantum dot 1 may have an average diameter of 1 nm to 10 nm. In comparison, the quantum dot 1 of Figure 1A may have an average diameter of 5 nm.

The figure IC shows a quantum dot 1, in addition to the

Semiconductor core la and the first enveloping layer lb additionally a second enveloping layer lc, so here a surface coating may have. The others

Enveloping layer 1c may be an organic coating, for example of silicone, acrylate or mixtures thereof. Is from the surface lb of each one

Quantum dot 1 the speech, then this corresponds according to the figure IC of the surface of the surface coating, which is in particular an organic coating. FIG. 2 shows possible terminal CC double bonds. The CC double bonds may be the CC double bonds of the quantum dots 1 and / or the second component 22. The CC double bonds may be part of a vinyl group, an acrylate group, a methacrylate group, a fluorinated vinyl group or an epoxy group.

FIG. 3A shows a two-dimensional network of

Quantum dots 1 and matrix material 2. Here form the

Quantum dots 1, the corresponding nodes of the network and the matrix material 2, the connecting lines between the nodes or quantum dots 1. Figure 3B shows a three-dimensional network

Quantum dots 1 and matrix material 2.

FIG. 4 schematically shows a method for producing a conversion element. In particular, the

Preparation by hydrosilylation. FIG. 4 shows the provision of a surface-functionalized

Quantum dot 1, so a quantum dot 1, the one

Surface coating having at least one end C-C double bond 11. In particular, the

end-capped C-C double bond is a vinyl group. To these coated quantum dots 1, a first component 21 is added. The first component 21 has in particular two Si-H groups. At least one Si-H group connects each with a terminal C-C double bond of

Quantum dot and forms a covalent bond.

In particular, the first component 21 is added in excess. This is followed by the addition of a second component 22 of the matrix material 2. In particular, the second component 22 is a bifunctionalized or bivinyl functionalized PDMS or PDPS. The second

Component 22 binds via at least one terminal C-C double bond to the first component 21, in particular to the terminal Si-H group. The Si (CH ₂ ) -Si units are not shown in FIG. 4 in contrast to FIG. 5 after reaction with the second component 22. In particular, the second component 22 is added in deficit, so that not all Si-H-functionalized quantum dots 1 are hydrosilylated. Subsequently, the

Polymerization of the functionalized quantum dots generated in step D), so that a network of quantum dots 1 and matrix material 2 is generated. The polymerization takes place here via a hydrosilylation.

FIG. 5 schematically shows a method for producing a conversion element. The method of FIG. 5

differs from the method of Figure 4 only in that the polymerization is not here by means

Hydrosilylation, but takes place free-radically. In particular, the free radical polymerization is achieved by addition of an initiator which is thermally or UV stabilized,

triggered. The result is a network of quantum dots 1, which are connected to the matrix material 2. In particular, the matrix material 2 has silicon atoms within the chain. In particular, the quantum dots 1 have a spacing, so that quenching of the quantum dots 1 is avoided due to too small a distance. FIG. 6 shows schematic side views of FIG

Optoelectronic devices 200 according to various embodiments. In particular, the optoelectronic component 200 is a light-emitting diode, in short LED. According to FIG. 6A, the light source 3 is a light-emitting diode chip or semiconductor chip which is applied to a carrier 4. Immediately above the LED chip 3 is the conversion element 100. Applied directly does not exclude here that a connecting means such as an adhesive between the respective components. Optionally, the light source 3 and the conversion element 100 are laterally surrounded by a reflector casting 6.

In the exemplary embodiment, as shown in FIG. 6B, the optoelectronic component 200 additionally has a lens 5. The lens 5 may be directly downstream of the conversion element 100.

In FIG. 6C, it can be seen that the conversion element 100 is located directly on the light-emitting diode chip 3 or on the light-emitting diode chip 3

Semiconductor layer sequence 3 of the optoelectronic component 200 is arranged. In this case, the reflector casting 6 is missing in comparison with FIG. 6A.

In the embodiment, as shown in Figure 6D, the conversion element 100 covers the entire surface of the

Semiconductor chips or the light source 3. In particular, the conversion element 100 has a constant thickness around the light source 3 around.

According to FIG. 6E, the light source or the semiconductor chip 3 is arranged in a recess 10 of an optoelectronic component 200. The recess 10 may be filled with a potting 9, for example made of silicone. The casting 9 is directly downstream of the conversion element 100. The

Optoelectronic component 200 also has a housing 21 on. In other words, the conversion element 100 is spatially spaced from the light source 3.

FIG. 6F shows that the conversion element 100 surrounds the semiconductor chip or light source 3 like a cap, as a result of which the conversion element 100 has a uniform thick layer in all directions. The conversion element 100 and the light source 3 may be arranged in a recess of a housing of an optoelectronic component 200 and surrounded by a potting 9.

The embodiment of Figure 6G shows

optoelectronic component 200 in which the

Conversion element 100, the light source 3 surrounds all around, so form-fitting and cohesively enveloped by its entire surface.

The ones described in connection with the figures

Embodiments and their features can also be combined with each other according to further embodiments, even if such combinations are not explicitly shown in the figures. Furthermore, the embodiments described in connection with the figures may have additional or alternative features as described in the general part.

The invention is not limited by the description based on the embodiments of these. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes any combination of features in the patent claims, even if this feature or combination itself is not explicitly described in the claims

Claims or embodiments is given. This patent application claims the priority of German Patent Application 10 2016 105 103.9, the disclosure of which is hereby incorporated by reference.

Reference sign list

100 conversion element

200 optoelectronic component

1 quantum dots

la semiconductor core

lb first enveloping layer

lc further enveloping layer or surface coating of the quantum dots

ld surface of a quantum dot

11 terminal C-C double bond

2 matrix material

21 first component

22 second component

3 light source or semiconductor chip

4 carriers

5 lens

6 reflector casting

9 potting

10 recess

21 housing

Claims

claims

1. A method for producing a conversion element (100) comprising the steps:

A) Provision of quantum dots (1) for

Wavelength conversion of radiation are set up and have a surface coating with terminal C-C double bonds (11),

B) providing a matrix material (2) comprising a first component (21) and a second component (22), wherein the first component (21) has at least two Si-H groups,

wherein the second component (22) has at least two terminal C-C double bonds,

C) attachment of the first component (21) to the terminal C-C double bond of the quantum dots (1) by means of

Hydrosilylation, wherein the connection carried out in step C) takes place thermally, the temperature being at least 80 ° C.,

D) bonding the second component (22) via at least one terminal C-C double bond of the second component (22) to the first component (21) after the first component (21) has been bonded in step C),

E) polymerization of those produced in step D)

functionalized quantum dots to produce a network of quantum dots (1) attached to the matrix material (2),

wherein the polymerization in step E) takes place radically with at least one thermal initiator or UV initiator, wherein at least one initiator has the following

Structural formula has:

2. The method according to claim 1,

wherein the second component (22) is a vinyl-functionalized polydimethylsiloxane, a vinyl-functionalized

Polydiphenylsiloxane or a mixture thereof.

3. Method according to at least one of the preceding

Claims,

wherein the polymerization carried out in step E)

done radically.

4. The method according to claim 3,

wherein a thermal initiator or UV initiator is used.

5. The method according to claim 4,

wherein the initiator is Lucrin-TPO-L.

6. Method according to at least one of the preceding

Claims,

wherein the second component (22) is added in excess.

7. The method according to at least one of the preceding

Claims,

wherein the first component (21) is added in excess.

8. Method according to at least one of the preceding

Claims,

wherein the terminal C-C double bond at least one

Quantum dot (1) Part of a vinyl residue, one

Methacrylate radical or acrylate radical.

9. Method according to at least one of the preceding

Claims,

wherein the polymerization in step E) is a hydrosilylation.

10. The method according to at least one of the preceding

Claims,

wherein the quantum dots (1) are selected from a group comprising InP, CdS, CdSe and CuInSe2.

11. The method according to at least one of the preceding

Claims,

wherein the surface coating (11) is an organic

Coating is the terminal C-C double bonds

having .

12. Conversion element (100) comprising

Quantum dots (1), which are set up for the wavelength conversion of radiation and the one

Have surface coating,

wherein adjacent quantum dots (1) via the matrix material (2) for spacing the quantum dots (1) are connected, so that a network of quantum dots (1) and matrix material (2) is formed, wherein the matrix material (2) of first and second components (21, 22) is formed, wherein the first component (21) has at least two Si-H groups, wherein the second component (22) has at least two terminal C-C double bonds, wherein the first component (21) to at least one terminal CC double bond of

Quantum dots (1) by means of hydrosilylation and the second component (22) via the terminal C-C double bonds of the second component (22) to the first component (21)

tethered,

wherein the network of quantum dots (1) and matrix material is produced by means of a radical polymerization with at least one thermal initiator or UV initiator, wherein at least one initiator has the following structural formula:

13. Optoelectronic component (200) with a

A semiconductor chip and a conversion element (100) obtainable by the method according to at least one of claims 1 to 11.