Ligands for nano-sized materials
The present invention relates to a compound suitable as ligand for binding to the surface of a semiconductor nanoparticle, said compound comprising an anchor group, a linker group and an organic functional group; a semiconductor nanoparticle have said ligand attached to the outermost particle surface; a composition, a formulation and a process for the preparation of said semiconductor nanoparticle; and an electronic device.
1 . A compound comprising, in the given order, an anchor group, AG, capable of binding to a surface of a semiconductor nanoparticle, followed by an electronically inert and conjugating interrupting linker group, L, followed by an organic functional group, FG,
wherein group FG is an electron transporting group selected from the following groups
wherein the dashed line represents the bonding position to the linker group,
wherein the compound has a molecular weight of 1000 g/mol or less, and
wherein the anchor group, AG, is selected from the group consisting of thiols or salts thereof, phosphonic acids or salts thereof, carboxylic acids or salts thereof, selenols or salts thereof, sulfinic acids or salts thereof, mercaptoesters or salts thereof, carbodithioic acids or salts thereof, boronic acids or salts thereof, and phosphines.
2 . The compound according to claim 1 , wherein the anchor group, AG, is selected from the group consisting of thiols or salts thereof, phosphonic acids or salts thereof, carboxylic acids or salts thereof, mercaptoesters or salts thereof, and boronic acids or salts thereof.
3 . The compound according to claim 1 , wherein the linker group, L, is selected from the group consisting of a straight-chain alkylene group having 1 to 20 C atoms, or a cyclic or branched alkylene group having 3 to 20 C atoms, wherein one or more non adjacent methylene groups can each be replaced by —O—, —S—, —C(═O)O—, —C(═S)S—, aromatic rings, or heteroaromatic rings.
4 . The compound according to claim 1 , wherein the compound is of formula (1)
wherein the following applies to the symbols and indices
wherein X is the anchor group, AG, and wherein
X is selected from —SH, —C(═O)OH, —NH 2 , —P(═O)(OH)(OH), —SeH, —P(R′R″), —S − Y + , —S(═O)OH, —S(═O)O − Y + , —C(═O)O − Y + , —OC(═O)R′″SH, —OC(═O)R′″S − Y + , —P(═O)(OH)(O − Y + ), —Se − Y + , —C(═S)SH, —C(═S)S − Y + , —B(OH) 2 , —B(OH)O − Y + , —B(O − Y + ) 2 , —B(O − ) 2 Z 2+ , —P(═O)(O − Y + )(O − Y + ) or —P(═O)(O − )(O − )Z 2+ ;
Y+ is selected from Na + , K + , Li + , ½Cd 2+ , ½Zn 2+ , ½Mg 2+ , ½Ca 2+ , ½Sr 2+ , ⅓In 3+ , ⅓Ga 3+ ;
Z 2+ is Cd 2+ , Zn 2+ , Mg 2+ , Ca 2+ , Sr 2+ ;
R′,R″ are, identically or differently, selected from H, linear or branched alkyl groups having 1 to 20 C atoms;
R′″ is selected from linear or branched alkyl groups having 1 to 10 C atoms; and
n is an integer from 0 to 20.
5 . A semiconductor nanoparticle comprising a core, one or more shell layers, and at least one ligand that is attached to the outermost surface of the one or more shell layers, wherein the at least one ligand is a compound according to claim 1 .
6 . A composition comprising:
at least one first semiconductor nanoparticle according to claim 5 , and at least one second semiconductor nanoparticle, or
said at least one first semiconductor nanoparticle and at least one further organic functional material selected from electron injecting materials, electron transporting materials, hole blocking materials, n-dopants, host materials, matrix materials, wide band gap materials, fluorescent emitter materials, delayed fluorescent materials, phosphorescent emitter materials, electron blocking materials, hole transporting materials, hole injecting materials, and p-dopants.
7 . A composition comprising at least one first semiconductor nanoparticle according to claim 5 , at least one second semiconductor nanoparticle and at least one further organic functional material selected from electron injecting materials, electron transporting materials, hole blocking materials, n-dopants, host materials, matrix materials, wide band gap materials, fluorescent emitter materials, delayed fluorescent materials, phosphorescent emitter materials, electron blocking materials, hole transport materials, hole injecting materials, and p-dopants.
8 . A method for preparation of a semiconductor nanoparticle according to claim 5 , comprising providing a semiconductor nanoparticle comprising a core and one or more shell layers into a solvent together with said compound to get a mixture.
9 . An electronic device comprising at least one semiconductor nanoparticle according to claim 5 or a composition comprising said at least one first semiconductor nanoparticle and at least one second semiconductor nanoparticle, or comprising said at least one first semiconductor nanoparticle and at least one further organic functional material selected from electron injecting materials, electron transporting materials, hole blocking materials, n-dopants, host materials, matrix materials, wide band gap materials, fluorescent emitter materials, delayed fluorescent materials, phosphorescent emitter materials, electron blocking materials, hole transporting materials, hole injecting materials, and p-dopants.
10 . The electronic device according to claim 9 , wherein the device is an electroluminescent device.
11 . The electronic device according to claim 9 , wherein the device is an electroluminescent device that comprises the semiconductor nanoparticle or the composition in the emissive layer.
12 . A semiconductor nanoparticle comprising a core, one or more shell layers and at least one ligand that is attached to the outermost surface of the one or more shell layers, wherein the semiconductor nanoparticle comprises at least two different ligands, wherein the ligands are selected from the compounds according to claim 1 .
13 . The semiconductor nanoparticle according to claim 12 , wherein the semiconductor nanoparticle comprises a first ligand and a second ligand, and wherein the first ligand comprises an organic functional group selected from an electron transporting group and wherein the second ligand comprises an organic functional group selected from a hole transporting group.
14 . A composition comprising at least one first semiconductor nanoparticle and at least one second semiconductor nanoparticle, each of said nanoparticles comprises a core, one or more shell layers, and at least one ligand that is attached to the outermost surface of the one or more shell layers, wherein the at least one ligand is a compound according to claim 1 , and wherein the at least one second semiconductor nanoparticle and the at least one first semiconductor nanoparticle differ from each other.
15 . The composition according to claim 14 , wherein the at least one first semiconductor nanoparticle further comprises at least one ligand attached to its outermost surface which comprises a delayed fluorescent group.
16 . The composition according to claim 14 , wherein the at least one first semiconductor nanoparticle further comprises at least one ligand attached to its outermost surface which comprises a phosphorescent group.
17 . A formulation comprising:
a compound according to claim 1 ; or
a semiconductor nanoparticle comprising a core, one or more shell layers and at least one ligand that is attached to the outermost surface of the one or more shell layers, characterized in that the at least one ligand is selected from said compound; or
a composition comprising said semiconductor nanoparticle and at least one second semiconductor nanoparticle, or comprising semiconductor nanoparticle and at least one further organic functional material selected from electron injecting materials, electron transporting materials, hole blocking materials, n-dopants, host materials, matrix materials, wide band gap materials, fluorescent emitter materials, delayed fluorescent materials, phosphorescent emitter materials, electron blocking materials, hole transporting materials, hole injecting materials, and
p-dopants; and
at least one solvent.