Quantum dot device and electronic device
A quantum dot device including an anode and a cathode, a light emitting layer disposed between the anode and the cathode, the light emitting layer comprising quantum dots, a first hole auxiliary layer disposed on the anode, the first hole auxiliary layer including poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate or a derivative thereof (PEDOT:PSS), a second hole auxiliary layer disposed on the first hole auxiliary layer and including a hole transport material different from the PEDOT:PSS, wherein the light emitting layer is disposed on the second hole auxiliary layer, wherein the first hole auxiliary layer has a first surface facing the anode and a second surface facing the second hole auxiliary layer, and the second surface includes a surface modification region including a surface modification material having a carboxylic acid group, a phosphonic acid group, a sulfonic acid group, or a salt thereof. An electronic device that includes the quantum dot device.
1. A quantum dot device, comprising
an anode and a cathode spaced apart from each other,
a light emitting layer disposed between the anode and the cathode, the light emitting layer comprising quantum dots;
a first hole auxiliary layer disposed between the anode and the light emitting layer, the first hole auxiliary layer comprising poly (3,4-ethylenedioxythiophene) polystyrenesulfonate or a derivative thereof (PEDOT:PSS),
a second hole auxiliary layer disposed between the first hole auxiliary layer and the light emitting layer, the second hole auxiliary layer comprising a hole transport material different from a material of the first hole auxiliary layer,
wherein the first hole auxiliary layer has a first surface facing the anode and a second surface facing the second hole auxiliary layer, and
the second surface of the first hole auxiliary layer comprises a surface modification region comprising a surface modification material including a carboxylic acid group, a phosphonic acid group, a sulfonic acid group, or a salt thereof,
wherein in the first hole auxiliary layer a volume of the surface modification material is less than a volume of the PEDOT:PSS.
2. The quantum dot device of claim 1 , wherein a HOMO energy level of the surface modification material is deeper than a HOMO energy level of the PEDOT:PSS and shallower than a HOMO energy level of the hole transport material.
3. The quantum dot device of claim 1 , wherein a HOMO energy level of the surface modification material is about 5.20 eV to about 5.60 eV.
4. The quantum dot device of claim 1 , wherein the surface modification material is represented by Chemical Formula 1:
wherein, in Chemical Formula 1,
Ar is a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C3 to C20 heteroaryl group, or any combination thereof,
L is a single bond, a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C3 to C20 heteroarylene group, or any combination thereof, and
R′ is a carboxylic acid group, a phosphonic acid group, a sulfonic acid group, or a respective salt of each thereof.
5. The quantum dot device of claim 4 , wherein Ar is a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, or any combination thereof.
6. The quantum dot device of claim 1 , wherein a thickness of the surface modification region is about 1 volume percent to about 30 volume percent of a total thickness of the first hole auxiliary layer.
7. The quantum dot device of claim 1 , wherein a thickness of the surface modification region is greater than or equal to about 1 nanometer and less than about 10 nanometers.
8. The quantum dot device of claim 1 , further comprising an electron auxiliary layer between the light emitting layer and the cathode,
wherein the electron auxiliary layer comprises n-type inorganic nanoparticles represented by Zn 1−x Q x O, wherein Q is one or more metals except Zn and 0≤x<0.5, or a mixture of the n-type inorganic nanoparticles and an alkali metal, an alkali metal compound, or any combination thereof.
9. The quantum dot device of claim 1 , further comprising an electron auxiliary layer between the light emitting layer and the cathode,
wherein the electron auxiliary layer comprises n-type inorganic nanoparticles represented by Zn 1−x Q x O, wherein Q is one or more metals other than Zn and 0≤x<0.5, or a mixture of the n-type inorganic nanoparticles and an alkali metal, an alkali metal compound, or any combination thereof.
10. An electronic device comprising the quantum dot device of claim 1 .
11. A quantum dot device, comprising
an anode and a cathode spaced apart from each other,
a light emitting layer disposed between the anode and the cathode, the light emitting layer comprising quantum dots, and
a first hole auxiliary layer between the anode and the light emitting layer,
wherein the first hole auxiliary layer comprises poly (3,4-ethylenedioxythiophene) polystyrenesulfonate or a derivative thereof (PEDOT:PSS) and a surface modification material having a carboxylic acid group, a phosphonic acid group, a sulfonic acid group, or a salt thereof,
wherein in the first hole auxiliary layer a volume of the surface modification material is less than a volume of the PEDOT:PSS.
12. The quantum dot device of claim 11 , wherein the surface modification material is present at a surface of the first hole auxiliary layer.
13. The quantum dot device of claim 12 , wherein a HOMO energy level of the surface of the first hole auxiliary layer is deeper than a HOMO energy level of the PEDOT:PSS.
14. The quantum dot device of claim 12 , wherein the first hole auxiliary layer comprises
a hole auxiliary region proximate to the anode and comprising the PEDOT:PSS, and
a surface modification region proximate to the light emitting layer and comprising the surface modification material.
15. The quantum dot device of claim 14 , wherein a thickness of the surface modification region is about 1 volume percent to about 30 volume percent of a total thickness of the first hole auxiliary layer.
16. The quantum dot device of claim 14 , wherein a thickness of the surface modification region is greater than or equal to about 1 nanometers and less than about 10 nanometers.
17. The quantum dot device of claim 11 , wherein the surface modification material is represented by Chemical Formula 1:
wherein, in Chemical Formula 1,
Ar is a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C3 to C20 heteroaryl group, or any combination thereof,
L is a single bond, a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C3 to C20 heteroarylene group, or any combination thereof, and
R′ is a carboxylic acid group, a phosphonic acid group, a sulfonic acid group, or a salt thereof.
18. The quantum dot device of claim 17 , wherein Ar is a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, or any combination thereof.
19. The quantum dot device of claim 11 , further comprising a second hole auxiliary layer disposed between the first hole auxiliary layer and the light emitting layer and comprising a hole transport material different from the PEDOT:PSS,
wherein a HOMO energy level of the surface modification material is deeper than a HOMO energy level of the PEDOT:PSS and shallower than a HOMO energy level of the hole transport material, and
a HOMO energy level of the quantum dots is deeper than a HOMO energy level of the hole transport material.
20. An electronic device comprising the quantum dot device of claim 11 .