Semiconductor device having quantum dots, display device, imaging system, and moving body
A semiconductor device includes an anode, a cathode, a first functional layer between the anode and cathode, and a second functional layer between the first functional layer and the cathode. The first functional layer contains a first quantum dot having a first ligand, and the second functional layer contains a second quantum dot having a second ligand different from the first ligand. The second ligand is an aromatic compound having a sulfide bond and an ester bond.
1. A semiconductor device comprising:
an anode;
a cathode;
a first functional layer between the anode and the cathode, the first functional layer containing a first quantum dot having a first ligand; and
a second functional layer between the first functional layer and the cathode, the second functional layer containing a second quantum dot having a second ligand different from the first ligand, the second ligand being an aromatic compound having a sulfide bond and an ester bond.
2. The semiconductor device according to claim 1 , wherein the first functional layer has a higher photoelectric conversion efficiency than the second functional layer.
3. The semiconductor device according to claim 1 , wherein the second functional layer has a thickness of 25% or less relative to a distance between the anode and the cathode.
4. The semiconductor device according to claim 1 , wherein the second functional layer has a thickness of 1.5% to 25% relative to a distance between the anode and the cathode.
5. The semiconductor device according to claim 1 , wherein the second ligand of the second quantum dot contained in the second functional layer is selected from a group consisting of 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, and 2-mercaptobenzoic acid.
6. The semiconductor device according to claim 1 , wherein the first functional layer and the second functional layer are each a quantum dot film defined by colloidal quantum dots.
7. The semiconductor device according to claim 1 , wherein at least one of the first and second functional layers contains a halogen selected from the group consisting of iodine, chlorine, bromine, and fluorine.
8. The semiconductor device according to claim 1 , wherein the first functional layer and the second functional layer act as photoelectric conversion layers.
9. The semiconductor device according to claim 1 , wherein the first and second quantum dots of the first and second functional layers contain PbS or PbSe.
10. The semiconductor device according to claim 1 ,
wherein the semiconductor device converts incoming light into a signal and outputs the signal.
11. An imaging system comprising:
the semiconductor device as set forth in claim 1 , and
a processor operable to process signals outputted from the semiconductor device.
12. A moving body comprising:
the semiconductor device as set forth in claim 1 ;
a moving device;
a processor operable to acquire information from signals outputted from the semiconductor device; and
a controller operable to control the moving device according to the information.
13. The semiconductor device according to claim 1 , wherein the first ligand has a thiol group; and
wherein the second ligand has a carboxy group, and the ester bond of the second ligand is included in the carboxy group.