# US 11,993,005 B1 · Process, apparatus and photoswitchable photoinitiators for locally polymerizing a starting material by dual color photopolymerization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,993,005 B1 - Document ID: US11993005B1 - Status: Granted - Kind: B1 - Application number: 18/137,640 - Filed: 2023-04-21 - Granted: 2024-05-28 - Earliest claimed: 2019-06-06 - Assignees: xolo GmbH - Applicants: xolo GmBH - Inventors: Yves Garmshausen; Marcus Reuter; Marin Regehly; Dirk Radzinski - Web page: https://patentgrep.com/patent/US11993005B1 ## CPC - B29C 64/135: the energy source being concentrated, e.g. scanning lasers or focused light sources - B29C 64/264: Arrangements for irradiation - B29C 64/282: of the same type, e.g. using different energy levels - B33Y 10/00: Processes of additive manufacturing - B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor - B33Y 70/00: Materials specially adapted for additive manufacturing - C08F 2/50: with sensitising agents - C08F 122/1006: {of polyhydric alcohols or polyhydric phenols, e.g. ethylene glycol dimethacrylate} - C08F 220/04: Acids; Metal salts or ammonium salts thereof - C08F 220/56: Acrylamide; Methacrylamide - C08F 222/102: {of dialcohols, e.g. ethylene glycol di(meth)acrylate or 1,4-butanediol dimethacrylate} - C08F 222/104: {of tetraalcohols, e.g. pentaerythritol tetra(meth)acrylate} - C09B 11/26: Triarylmethane dyes in which at least one of the aromatic nuclei is heterocyclic {(phthaleins C09B11/24)} - C09B 11/28: Pyronines {; Xanthon, thioxanthon, selenoxanthan, telluroxanthon dyes} - C09B 57/00: Other synthetic dyes of known constitution - C09B 69/10: Polymeric dyes; Reaction products of dyes with monomers or with macromolecular compounds - G03F 7/0037: {Production of three-dimensional images} - G03F 7/029: Inorganic compounds; Onium compounds; Organic compounds having hetero atoms other than oxygen, nitrogen or sulfur - G03F 7/031: Organic compounds not covered by group G03F7/029 - G03F 7/2051: {Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source (G03F7/70 takes precedence)} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C09B: ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES {, e.g. PIGMENTS}; MORDANTS; LAKES (fermentation or enzyme using processes to synthesise a desired chemical compound C12P) - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract A process, an apparatus, and photoswitchable photoinitiators for polymerizing a starting material by dual color photopolymerization. In particular, photoinitiators are provided, which cause curing of photopolymerizable formulations upon illumination with two different wavelengths. ## Claims ### Claim 1 A method to form a three-dimensional shape, the method comprising dual color photopolymerization, comprising: taking up a polymerizable starting material in a container for the polymerizable starting material, said polymerizable starting material containing photoinitiator molecules which can be excited by sequential optical excitation into a reactive state in which the photoinitiator molecules locally initiate polymerization of the starting material; and photopolymerizing in a 3d printing process the starting material in a local volume of the container by illuminating the light of the first wavelength and the light of the second wavelength into the local volume of the container, whereby in the local volume the photoinitiator molecules, due to the absorption of the light of the first wavelength, are converted from an initial state in which the photoinitiator molecules substantially do not absorb the light of the second wavelength into an intermediate state with changed optical properties compared to the initial state, such that the photoinitiator molecules in the intermediate state absorb the light of the second wavelength; and the photoinitiator molecules are transferred from the intermediate state to the reactive state due to the absorption of the light of the second wavelength, which triggers the polymerization locally; wherein the photoinitiator molecules are represented by the following formula (I) wherein Ra and Rb are selected independently from unsubstituted or substituted aryl, unsubstituted or substituted alkyne or a linked to each other to form a unsubstituted or substituted ring structure, Y is selected from O, S, or N; where Y is N, the substituent contains the atoms necessary to complete a cyclic structure with R8 selected from the group consisting of benzimidazole, indoline, indole, dihydroquinoline, and tetrahydroquinoline; wherein Z is selected from N or CR4; wherein R3 to R8 are independently selected from the group consisting of H; D; halogen; NO2; CN; OH; SH; substituted or unsubstituted C1-C2M-alkyl; substituted or unsubstituted C3-C20-cycloalkyl; substituted or unsubstituted C6-C48-aryl; substituted or unsubstituted C2-C42-heteroaryl; substituted or unsubstituted C2-C49-alkyl acyl; substituted or unsubstituted C2-C49-aryl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy, and NH2; substituted or unsubstituted C1-C20-alkyl ester; substituted or unsubstituted C6-C48-aryl ester; substituted or unsubstituted C1-C20 alkyl amide; substituted or unsubstituted C6-C48-aryl amide; NR′2, SiR′3, —O—SiR′3 wherein R′ is independently selected from the group consisting of substituted or unsubstituted C1-C20-alkyl and substituted or unsubstituted C6-C48-aryl, two R′ may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C2-C20-alkynyl and substituted or unsubstituted C2-C20-alkenyl; wherein the one or more substituents, if present in one or more of R3-R8, are independently selected from the group consisting of D; halogen; NO2; CN, C2-C49-alkyl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy; substituted or unsubstituted C2-C49-aryl acyl; (meth)acrylate; tosyl; NH2; and OH; and/or wherein two adjacent groups of R5-R8 may be linked to each other to form a fused ring structure; and wherein at least one of R3-R8, is selected from one of the following structures: wherein R14 to R25 are independently selected from the group consisting of H; D; halogen; NO2; CN; OH; SH; substituted or unsubstituted C1-C2M-alkyl; substituted or unsubstituted C3-C20-cycloalkyl; substituted or unsubstituted C6-C48-aryl; substituted or unsubstituted C2-C42-heteroaryl; substituted or unsubstituted C2-C49-alkyl acyl; substituted or unsubstituted C2-C49-aryl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy, and NH2; substituted or unsubstituted C1-C20-alkyl ester; substituted or unsubstituted C6-C48-aryl ester; substituted or unsubstituted C1-C20 alkyl amide; substituted or unsubstituted C6-C48-aryl amide; NR′2, SiR′3, —O—SiR′3 wherein R′ is independently selected from the group consisting of substituted or unsubstituted C1-C20-alkyl and substituted or unsubstituted C6-C48-aryl, two R′ may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C2-C20-alkynyl and substituted or unsubstituted C2-C20-alkenyl; wherein the one or more substituents, if present in one or more of R14-R25, are independently selected from the group consisting of D; halogen; NO2; CN, C2-C49-alkyl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy; substituted or unsubstituted C2-C49-aryl acyl; (meth)acrylate; tosyl; NH2; and OH; and R15 and R16 may be linked to each other to form a unsubstituted or substituted ring structure. ### Claim 2 A 3d printing process to form a three-dimensional shape for locally polymerizing a starting material by dual color photopolymerization, comprising: photopolymerizing in the 3d printing process a polymerizable starting material in a local volume by illuminating light of a first wavelength and light of a second wavelength, different from the first wavelength, into the local volume, the polymerizable starting material containing photoinitiator molecules configured to be converted by sequential optical excitation into a reactive state in which the photoinitiator molecules locally trigger polymerization of the starting material, whereby in the local volume the photoinitiator molecules are converted, due to the absorption of the light of the first wavelength, from an initial state in which the photoinitiator molecules substantially do not absorb the light of the second wavelength, into an intermediate state with changed optical properties compared to the initial state, such that the photoinitiator molecules in the intermediate state absorb the light of the second wavelength; and the photoinitiator molecules are transferred from the intermediate state to the reactive state due to the absorption of the light of the second wavelength, which triggers the polymerization locally; wherein the photoinitiator molecules are represented by the following formula (I) wherein Ra and Rb are selected independently from unsubstituted or substituted aryl, unsubstituted or substituted alkyne or a linked to each other to form a unsubstituted or substituted ring structure, Y is selected from O, S, or N; where Y is N, the substituent contains the atoms necessary to complete a cyclic structure with R8 selected from the group consisting of benzimidazole, indoline, indole, dihydroquinoline, and tetrahydroquinoline; wherein Z is selected from N or CR4; wherein R3 to R8 are independently selected from the group consisting of H; D; halogen; NO2; CN; OH; SH; substituted or unsubstituted C1-C2M-alkyl; substituted or unsubstituted C3-C20-cycloalkyl; substituted or unsubstituted C6-C48-aryl; substituted or unsubstituted C2-C42-heteroaryl; substituted or unsubstituted C2-C49-alkyl acyl; substituted or unsubstituted C2-C49-aryl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy, and NH2; substituted or unsubstituted C1-C20-alkyl ester; substituted or unsubstituted C6-C48-aryl ester; substituted or unsubstituted C1-C20 alkyl amide; substituted or unsubstituted C6-C48-aryl amide; NR′2, SiR′3, —O—SiR′3, wherein R′ is independently selected from the group consisting of substituted or unsubstituted C1-C20-alkyl and substituted or unsubstituted C6-C48-aryl, two R′ may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof, substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C2-C20-alkynyl and substituted or unsubstituted C2-C20-alkenyl; wherein the one or more substituents, if present in one or more of R3-R8, are independently selected from the group consisting of D; halogen; NO2; CN, C2-C49-alkyl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy; substituted or unsubstituted C2-C49-aryl acyl; (meth)acrylate; tosyl; NH2; and OH; and/or wherein two adjacent groups of R5-R8 may be linked to each other to form a fused ring structure; and wherein at least one of R3-R8, is selected from one of the following structures: wherein R14 to R25 are independently selected from the group consisting of H; D; halogen; NO2; CN; OH; SH; substituted or unsubstituted C1-C2M-alkyl; substituted or unsubstituted C3-C20-cycloalkyl; substituted or unsubstituted C6-C48-aryl; substituted or unsubstituted C2-C42-heteroaryl; substituted or unsubstituted C2-C49-alkyl acyl; substituted or unsubstituted C2-C49-aryl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy, and NH2; substituted or unsubstituted C1-C20-alkyl ester; substituted or unsubstituted C6-C48-aryl ester; substituted or unsubstituted C1-C20 alkyl amide; substituted or unsubstituted C6-C48-aryl amide; NR′2, SiR′3, —O—SiR′3 wherein R′ is independently selected from the group consisting of substituted or unsubstituted C1-C20-alkyl and substituted or unsubstituted C6-C48-aryl, two R′ may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof; substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C2-C20-alkynyl and substituted or unsubstituted C2-C20-alkenyl; or wherein R19 is selected from substituted or unsubstituted C1-C10-alkyl; substituted or unsubstituted C3-C10-cycloalkyl; substituted or unsubstituted C6-C32-aryl: substituted or unsubstituted C2-C28-heteroaryl, substituted or unsubstituted C2-C20-alkynyl and substituted or unsubstituted C2-C20-alkenyl, the substituent may contains the atoms necessary to complete a cyclic structure with one of R5—R8 or R10—R13 forming an anthracene, thioxanthone or fluorenone; wherein the one or more substituents, if present in one or more of R14-R25, are independently selected from the group consisting of D; halogen; NO2; CN, C2-C49-alkyl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy; substituted or unsubstituted C2-C49-aryl acyl; (meth)acrylate; tosyl; NH2; and OH; and R15 and R16 may be linked to each other to form a unsubstituted or substituted ring structure. ### Claim 3 (depends on 2) A process according to claim 2, characterized in that the light of the first wavelength and the light of the second wavelength are simultaneously illuminated into the local volume. ### Claim 4 (depends on 2) A process according to claim 2, characterized in that the light of the second wavelength is illuminated into the local volume after illuminating the light of the first wavelength in the local volume has ended, the light of the second wavelength being illuminated before the end of a decay time of the intermediate state of the photoinitiator molecules. ### Claim 5 (depends on 2) A process according to claim 2, characterized in that the photoinitiator molecules in the intermediate state substantially do not absorb the light of the first wavelength. ### Claim 6 (depends on 2) A process according to claim 2, characterized in that the photoinitiator molecules are converted from the intermediate state to the initial state due to the absorption of light of a third wavelength in volumes where no polymerization is desired. ### Claim 7 (depends on 2) A process according to claim 2, characterized in that the photoinitiator molecules are converted into a reactive state due to the sequential absorption of light of the second wavelength which triggers a polymerization in the local volume. ### Claim 8 (depends on 2) A process according to claim 2, characterized in that the photoinitiator molecules are converted into a reactive state due to the absorption of the light of the second wavelength, which triggers a radical polymerization in the local volume. ### Claim 9 (depends on 2) A process according to claim 2, characterized in that the photoinitiator molecule is represented by the following formula (II) wherein X is selected from S, CR1R2, or NR1; Y is selected from O, S, or NRc; when Y is N, the substituent Rc contains the atoms necessary to complete a cyclic structure with R8 selected from the group consisting of benzimidazole, indoline, indole, dihydroquinoline, and tetrahydroquinoline; Z is selected from N or CR4; and R1 to R13 are independently selected as defined in R3 to R8 regarding formula (I) above. ### Claim 10 (depends on 2) A process according to claim 2, characterized in that R14, R15, and R16 are independently selected from H, D, CN, halogen, substituted or unsubstituted C1-C10-alkyl; substituted or unsubstituted C3-C10-cycloalkyl; substituted or unsubstituted C6-C32-aryl; substituted or unsubstituted C2-C28-heteroaryl. ### Claim 11 (depends on 2) A process according to claim 2, characterized in that R19 is selected from substituted or unsubstituted phenyl of naphthyl. ### Claim 12 (depends on 2) A process according to claim 2, characterized in that R14 is independently selected from the group consisting of OH: substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy; NR′2, SiR′3, —O—SiR′3 wherein R′ is independently selected from the group consisting of substituted or unsubstituted C1-C20-alkyl and substituted or unsubstituted C6-C48-aryl, two R′ may form a ring structure; and R15 and R16 are independently selected from H, D, CN, substituted or unsubstituted C1-C10-alkyl; substituted or unsubstituted C3-C10-cycloalkyl; substituted or unsubstituted C6-C32-aryl; substituted or unsubstituted C2-C28-heteroaryl. ### Claim 13 (depends on 2) A process according to claim 2, characterized in that R14 and R15 are OH: substituted or unsubstituted C1-C20-alkoxy: substituted or unsubstituted C6-C48-aryloxy. ### Claim 14 (depends on 2) A process according to claim 2, characterized in that the photoinitiator molecule used in the process according to the invention comprises one or more of the following compounds: ### Claim 15 (depends on 2) A process according to claim 2, characterized in that the polymerizable starting material further contains a co-initiator and/or a sensitizer. ### Claim 16 (depends on 2) A process according to claim 2, characterized in that the polymerizable starting material further contains an additive, an acid and/or a base. ### Claim 17 (depends on 2) A process according to claim 2, characterized in that a light beam of light of the first wavelength and a light beam of light of the second wavelength are illuminated at least partially overlapping in the local volume. ### Claim 18 (depends on 2) A process according to claim 2, characterized in that the starting material is polymerized in several local volumes by means of photopolymerization and thus a three-dimensional shaped body is produced in the starting material. ### Claim 19 A 3d printing process to form a three-dimensional shape for locally polymerizing a starting material by dual color photopolymerization, comprising: photopolymerizing in the 3d printing process a polymerizable starting material in a local volume by illuminating light of a first wavelength and light of a second wavelength, different from the first wavelength, into the local volume, the polymerizable starting material containing photoinitiator molecules configured to be converted by sequential optical excitation into a reactive state in which the photoinitiator molecules locally trigger polymerization of the starting material, whereby in the local volume the photoinitiator molecules are converted, due to the absorption of the light of the first wavelength, from an initial state in which the photoinitiator molecules substantially do not absorb the light of the second wavelength, into an intermediate state with changed optical properties compared to the initial state, such that the photoinitiator molecules in the intermediate state absorb the light of the second wavelength; and the photoinitiator molecules are transferred from the intermediate state to the reactive state due to the absorption of the light of the second wavelength, which triggers the polymerization locally; wherein the photoinitiator molecules are represented by the following formula (I) wherein Ra and Rb are selected independently from unsubstituted or substituted aryl, unsubstituted or substituted alkyne or a linked to each other to form a unsubstituted or substituted ring structure, Y is selected from O, S, or N; where Y is N, the substituent contains the atoms necessary to complete a cyclic structure with R8 selected from the group consisting of benzimidazole, indoline, indole, dihydroquinoline, and tetrahydroquinoline; wherein Z is selected from N or CR4; wherein R3 to R8 are independently selected from the group consisting of H; D; halogen; NO2; CN; OH; SH; substituted or unsubstituted C1-C2M-alkyl; substituted or unsubstituted C3-C20-cycloalkyl; substituted or unsubstituted C6-C48-aryl; substituted or unsubstituted C2-C42-heteroaryl; substituted or unsubstituted C2-C49-alkyl acyl; substituted or unsubstituted C2-C49-aryl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy, and NH2; substituted or unsubstituted C1-C20-alkyl ester; substituted or unsubstituted C6-C48-aryl ester; substituted or unsubstituted C1-C20 alkyl amide; substituted or unsubstituted C6-C48-aryl amide; NR′2, SiR′3, —O—SiR′3, wherein R′ is independently selected from the group consisting of substituted or unsubstituted C1-C20-alkyl and substituted or unsubstituted C6-C48-aryl, two R′ may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof, substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C2-C20-alkynyl and substituted or unsubstituted C2-C20-alkenyl; wherein the one or more substituents, if present in one or more of R3-R8, are independently selected from the group consisting of D; halogen; NO2; CN, C2-C49-alkyl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy; substituted or unsubstituted C2-C49-aryl acyl; (meth)acrylate; tosyl; NH2; and OH; and/or wherein two adjacent groups of R5—R8 may be linked to each other to form a fused ring structure; and wherein at least one of R3—R8, is selected from one of the following structures: wherein R14 to R25 are independently selected from the group consisting of H; D; halogen; NO2; CN; OH; SH; substituted or unsubstituted C1-C20-alkyl; substituted or unsubstituted C3-C20-cycloalkyl; substituted or unsubstituted C6-C48-aryl; substituted or unsubstituted C2-C42-heteroaryl; substituted or unsubstituted C2-C49-alkyl acyl; substituted or unsubstituted C2-C49-aryl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy, and NH2; substituted or unsubstituted C1-C20-alkyl ester; substituted or unsubstituted C6-C48-aryl ester; substituted or unsubstituted C1-C20 alkyl amide; substituted or unsubstituted C6-C48-aryl amide; NR′2, SiR′3, —O—SiR′3, wherein R′ is independently selected from the group consisting of substituted or unsubstituted C1-C20-alkyl and substituted or unsubstituted C6-C48-aryl, two R′ may form a ring structure; substituted or unsubstituted carboxylic acids and salts thereof, substituted or unsubstituted sulfonic acids and salts thereof; substituted or unsubstituted sulfonic esters; substituted or unsubstituted sulfonic amides; formyl; ether, thioether; carbonate; carbonate ester; sulfates; boronic acids; boronic esters; phosphonic acids; phosphonic esters; phosphines; phosphates; peroxycarbonic acids; thiocarbonic acids; sulfinic acids; sulfinic esters; sulfonates; thiolesters, sulfoxides; sulfones; hydrazides; thioaldehydes; ketones; thioketones; oximes; hydrazines; nitroso; azo; diazo; diazonium; isocyanides; cyanate; isocyanate; thiocyanate; isothiocyanate; hydroperoxide; peroxide; acetals; ketal; orthoester; orthocarbonate esters; ammonium; imines; imides; azide; nitrate; isonitrile; nitrosoxy; substituted or unsubstituted carbamates; substituted or unsubstituted ethers; substituted or unsubstituted polyether carbamates; substituted or unsubstituted arylazo; substituted or unsubstituted C2-C20-alkynyl and substituted or unsubstituted C2-C20-alkenyl; wherein the one or more substituents, if present in one or more of R14-R25, are independently selected from the group consisting of D; halogen; NO2; CN, C2-C49-alkyl acyl; substituted or unsubstituted C1-C20-alkoxy; substituted or unsubstituted C6-C48-aryloxy; substituted or unsubstituted C2-C49-aryl acyl; (meth)acrylate; tosyl; NH2; and OH; and R15 and R16 may be linked to each other to form a unsubstituted or substituted ring structure; wherein the photoinitiator molecule is represented by the following formula (II) wherein X is selected from S, CR1R2, or NR1; Y is selected from O, S, or NRc; when Y is N, the substituent Rc contains the atoms necessary to complete a cyclic structure with R8 selected from the group consisting of benzimidazole, indoline, indole, dihydroquinoline, and tetrahydroquinoline; Z is selected from N or CR4; and R1, R2 and R9 are independently selected as defined in R3 to R8 regarding formula (I) above; wherein R10-R13 of the photoinitiator molecule represented by the following formula (II) are independently selected from the group consisting of H and electron withdrawing groups (EWG) and R3-R8 are independently selected from the group consisting of H and substituents belonging to the following formulae: and wherein R14-R25 are independently selected as defined in R14 to R25 regarding formula (I) above; or wherein R3-R8 and R10-R13 of the photoinitiator molecule represented by the following formula (II) are independently selected from the group consisting of H and electron withdrawing groups (EWG); or wherein R10-R13 of the photoinitiator molecule represented by the following formula (II) are independently selected from the group consisting of H and electron withdrawing groups (EWG), and one of R5-R8 is selected from unsubstituted or substituted arylacyl; or unsubstituted or substituted alkylacyl, wherein the other of R5-R8 and R3 and R4 are independently selected as defined in R3 to R8 regarding formula (I) above; or at least one of R6, R7 and R12 is selected from the group consisting of CF3, SO2Me, SO2NH2, CN, F, NO2, C6-aryl, unsubstituted C6-arylacyl of the following formulae: dimethoxy-substituted arylacyl of the formula methoxy-substituted arylacyl of the formula fluorine-substituted arylacyl of the following formula alternatively of the formula and C6-aryl, wherein R1-R5, R8-R11 and R13 are independently selected as defined in R3 to R8 regarding formula (I) above.