Light emitting diode device, preparation method therefor, light emitting substrate, and light emitting apparatus
A light-emitting-diode device and a fabricating method thereof, a light emitting base plate and a light emitting apparatus. The light-emitting-diode device includes: an anode layer, a luminescent layer, a charge-carrier balancing layer, an electron transporting layer and a cathode layer that are arranged in stack; and a hole mobility of the charge-carrier balancing layer is greater than an electron mobility of the charge-carrier balancing layer, an LUMO energy level of the charge-carrier balancing layer is shallower than an LUMO energy level of the electron transporting layer, and an HOMO energy level of the charge-carrier balancing layer is shallower than an HOMO energy level of the luminescent layer.
1 . A light-emitting-diode device, wherein the light-emitting-diode comprises:
an anode layer, a luminescent layer, a charge-carrier balancing layer, an electron transporting layer and a cathode layer that are arranged in stack; and
a hole mobility of the charge-carrier balancing layer is greater than an electron mobility of the charge-carrier balancing layer, an LUMO energy level of the charge-carrier balancing layer is shallower than an LUMO energy level of the electron transporting layer, and a HOMO energy level of the charge-carrier balancing layer is shallower than a HOMO energy level of the luminescent layer.
2 . The light-emitting-diode device according to claim 1 , wherein the HOMO energy level of the charge-carrier balancing layer is shallower than a HOMO energy level of the electron transporting layer.
3 . The light-emitting-diode device according to claim 2 , wherein a difference between the LUMO energy level of the charge-carrier balancing layer and the LUMO energy level of the electron transporting layer is greater than or equal to 0.6 eV, and less than or equal to 1.5 eV.
4 . The light-emitting-diode device according to claim 2 , wherein the electron mobility of the charge-carrier balancing layer is less than an electron mobility of the electron transporting layer by no less than 2 orders of magnitude.
5 . The light-emitting-diode device according to claim 1 , wherein a difference between the LUMO energy level of the charge-carrier balancing layer and the LUMO energy level of the electron transporting layer is greater than or equal to 0.6 eV, and less than or equal to 1.5 eV.
6 . The light-emitting-diode device according to claim 1 , wherein the electron mobility of the charge-carrier balancing layer is less than an electron mobility of the electron transporting layer by no less than 2 orders of magnitude.
7 . The light-emitting-diode device according to claim 1 , wherein the light-emitting-diode device further comprises a hole transporting layer provided between the anode layer and the luminescent layer, and a hole mobility of the hole transporting layer is greater than the hole mobility of the charge-carrier balancing layer by 1 order of magnitude or less than the hole mobility of the charge-carrier balancing layer by 1 order of magnitude.
8 . The light-emitting-diode device according to claim 1 , wherein an absolute value of the LUMO energy level of the charge-carrier balancing layer is greater than or equal to 2.35 eV, and an absolute value of the HOMO energy level of the charge-carrier balancing layer is less than or equal to 6.3 eV.
9 . The light-emitting-diode device according to claim 1 , wherein a material of the charge-carrier balancing layer comprises a first compound, wherein the first compound is selected from compounds represented by the following first general formula:
wherein L (n) represents solubilizing groups;
n represents a quantity of the solubilizing groups, wherein n is greater than or equal to 2; and
Ar 1 , Ar 2 and Ar 3 are the same or different, wherein at least one of Ar 1 , Ar 2 and Ar 3 is selected from compounds represented by a second general formula, and the other are selected from compounds represented by a third general formula;
the second general formula is:
wherein A is selected from nitrogen or carbon; and
the third general formula is any one of the following general formulas:
wherein X is selected from N, C, O or S; and
R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are the same or different, and are individually independently selected from any one of substituted alkyl having 1 to 30 carbon atoms, unsubstituted alkyl having 1 to 30 carbon atoms, substituted alkoxy having 1 to 30 carbon atoms, unsubstituted alkoxy having 1 to 30 carbon atoms, aryl having 6 to 40 carbon atoms, aryloxy having 6 to 40 carbon atoms and aralkyl having 7 to 40 carbon atoms.
10 . The light-emitting-diode device according to claim 9 , wherein the solubilizing groups are selected from any one of straight-chain alkyl having 2 to 40 carbon atoms, branch-chain alkyl having 2 to 40 carbon atoms, cyclic alkyl having 2 to 40 carbon atoms, straight-chain alkoxy having 2 to 40 carbon atoms, branch-chain alkoxy having 2 to 40 carbon atoms and cyclic alkoxy having 2 to 40 carbon atoms.
11 . The light-emitting-diode device according to claim 9 , wherein a molecular weight of the first compound is less than or equal to 5000 g/mol.
12 . The light-emitting-diode device according to claim 11 , wherein the molecular weight of the first compound is less than or equal to 4000 g/mol.
13 . The light-emitting-diode device according to claim 1 , wherein a thickness of the charge-carrier balancing layer is greater than or equal to 2 micrometers, and less than or equal to 40 micrometers.
14 . The light-emitting-diode device according to claim 13 , wherein the thickness of the charge-carrier balancing layer is greater than or equal to 5 micrometers, and less than or equal to 25 micrometers.
15 . The light-emitting-diode device according to claim 1 , wherein the luminescent layer is a quantum-dot luminescent layer.
16 . A light emitting base plate, wherein the light emitting base plate comprises:
a substrate, and a plurality of the light-emitting-diode devices according to claim 1 that are provided on one side of the substrate, wherein the anode layer or the cathode layer is close to the substrate.
17 . A light emitting apparatus, wherein the light emitting apparatus comprises the light emitting base plate according to claim 16 .
18 . A fabricating method of a light-emitting-diode device, wherein the fabricating method comprises:
sequentially forming an anode layer, a luminescent layer, a charge-carrier balancing layer, an electron transporting layer and a cathode layer; or
sequentially forming a cathode layer, an electron transporting layer, a charge-carrier balancing layer, a luminescent layer and an anode layer;
wherein a hole mobility of the charge-carrier balancing layer is greater than an electron mobility of the charge-carrier balancing layer, an LUMO energy level of the charge-carrier balancing layer is shallower than an LUMO energy level of the electron transporting layer, and a HOMO energy level of the charge-carrier balancing layer is shallower than a HOMO energy level of the luminescent layer.
19 . The fabricating method according to claim 18 , wherein the step of sequentially forming the anode layer, the luminescent layer, the charge-carrier balancing layer, the electron transporting layer and the cathode layer comprises:
sequentially forming the anode layer and the luminescent layer;
spin-coating a solution of a first compound onto one side of the luminescent layer that is away from the anode layer, and drying the solution of the first compound, to form the charge-carrier balancing layer; and
sequentially forming the electron transporting layer and the cathode layer on one side of the charge-carrier balancing layer that is away from the anode layer; and
the step of sequentially forming the cathode layer, the electron transporting layer, the charge-carrier balancing layer, the luminescent layer and the anode layer comprises:
sequentially forming the cathode layer and the electron transporting layer;
spin-coating the solution of the first compound onto one side of the electron transporting layer that is away from the cathode layer, and drying the solution of the first compound, to form the charge-carrier balancing layer; and
sequentially forming the luminescent layer and the anode layer on one side of the charge-carrier balancing layer that is away from the cathode layer;
wherein the first compound is selected from compounds represented by the following first general formula:
wherein L (n) represents solubilizing groups;
n represents a quantity of the solubilizing groups, wherein n is greater than or equal to 2; and
Ar 1 , Ar 2 and Ar 3 are the same or different, wherein at least one of Ar 1 , Ar 2 and Ar 3 is selected from compounds represented by a second general formula, and the other are selected from compounds represented by a third general formula;
the second general formula is:
wherein A is selected from nitrogen or carbon; and
the third general formula is any one of the following general formulas:
wherein X is selected from N, C, O or S; and
R 1 , R 2 , R 3 , RA, R 5 , R 6 , R 7 and R 8 are the same or different, and are individually independently selected from any one of substituted alkyl having 1 to 30 carbon atoms, unsubstituted alkyl having 1 to 30 carbon atoms, substituted alkoxy having 1 to 30 carbon atoms, unsubstituted alkoxy having 1 to 30 carbon atoms, aryl having 6 to 40 carbon atoms, aryloxy having 6 to 40 carbon atoms and aralkyl having 7 to 40 carbon atoms.
20 . The fabricating method according to claim 19 , wherein the step of sequentially forming the anode layer and the luminescent layer comprises:
forming the anode layer;
forming the hole transporting layer on one side of the anode layer; and
forming the luminescent layer on one side of the hole transporting layer that is away from the anode layer; and
the step of sequentially forming the luminescent layer and the anode layer on the one side of the charge-carrier balancing layer that is away from the cathode layer comprises:
forming the luminescent layer on one side of the charge-carrier balancing layer that is away from the cathode layer;
forming the hole transporting layer on one side of the luminescent layer that is away from the charge-carrier balancing layer; and
forming the anode layer on one side of the hole transporting layer that is away from the charge-carrier balancing layer;
wherein a hole mobility of the hole transporting layer is greater than the hole mobility of the charge-carrier balancing layer by 1 order of magnitude or less than the hole mobility of the charge-carrier balancing layer by 1 order of magnitude.