High signal-to-noise ratio photoelectric conversion element
To improve an SN ratio of a photoelectric conversion element. A photoelectric conversion element ( 10 ) includes an anode ( 12 ), a cathode ( 16 ), an active layer ( 14 ) provided between the anode and the cathode, and a hole transport layer ( 13 ) provided between the anode and the active layer. The active layer includes a p-type semiconductor material, which is a polymer compound having an absorption peak wavelength of 900 nm or higher, and an n-type semiconductor material, and an energy gap between an LUMO of the n-type semiconductor material contained in the active layer and a HOMO of a hole transport material contained in the hole transport layer is less than 0.9 eV.
1. A photoelectric conversion element, comprising an anode, a cathode, an active layer provided between the anode and the cathode, and a hole transport layer provided between the anode and the active layer, wherein the active layer includes a p-type semiconductor material, which is a polymer compound having an absorption peak wavelength of 900 nm or higher, and an n-type semiconductor material, and an energy gap between an Lowest Unoccupied Molecular Orbital (LUMO) of the n-type semiconductor material contained in the active layer and a Highest Occupied Molecular Orbital (HOMO) of a hole transport material contained in the hole transport layer is less than 0.9 eV, wherein the photoelectric conversion element has a signal-to-noise ratio of 1.4×103 or greater.
2. The photoelectric conversion element according to claim 1 , wherein the absorption peak wavelength of the p-type semiconductor material is not less than 900 nm but not more than 2000 nm, and the energy gap is in a range of 0.5 eV to 0.8 eV.
3. The photoelectric conversion element according to claim 2 , wherein the n-type semiconductor material is a fullerene derivative.
4. The photoelectric conversion element according to claim 2 , wherein the p-type semiconductor material is a polymer compound having a structural unit having a thiophene skeleton.
5. The photoelectric conversion element according to claim 2 , being a light detecting element.
6. The photoelectric conversion element according to claim 1 , wherein the n-type semiconductor material is a fullerene derivative.
7. The photoelectric conversion element according to claim 6 , wherein the fullerene derivative is one or more compounds selected from the group consisting of compounds represented by formulae (N-a) to (N-f) below,
wherein R a is an alkyl group, an aryl group, a monovalent heterocyclic group, or a group having an ester structure, where if there are a plurality of R a in the formula, the plurality of R a may be identical with or different from one another, and
R b is an alkyl group or an aryl group,
where if there are a plurality of R b in the formula, the plurality of R b may be identical with or different from one another.
8. The photoelectric conversion element according to claim 7 , wherein the fullerene derivative is the compound represented by formula (N-a), (N-b), (N-e), or (N-f).
9. The photoelectric conversion element according to claim 8 , wherein the fullerene derivative is C 60 PCBM or KLOC-6.
10. The photoelectric conversion element according to claim 9 , wherein the p-type semiconductor material is a polymer compound having a structural unit having a thiophene skeleton.
11. The photoelectric conversion element according to claim 6 , wherein the p-type semiconductor material is a polymer compound having a structural unit having a thiophene skeleton.
12. The photoelectric conversion element according to claim 6 , being a light detecting element.
13. The photoelectric conversion element according to claim 7 , wherein the p-type semiconductor material is a polymer compound having a structural unit having a thiophene skeleton.
14. The photoelectric conversion element according to claim 7 , being a light detecting element.
15. The photoelectric conversion element according to claim 8 , wherein the p-type semiconductor material is a polymer compound having a structural unit having a thiophene skeleton.
16. The photoelectric conversion element according to claim 8 , being a light detecting element.
17. The photoelectric conversion element according to claim 9 , being a light detecting element.
18. The photoelectric conversion element according to claim 1 , wherein the p-type semiconductor material is a polymer compound having a structural unit having a thiophene skeleton.
19. The photoelectric conversion element according to claim 18 , being a light detecting element.
20. The photoelectric conversion element according to claim 1 , being a light detecting element.
21. The photoelectric conversion element according to claim 1 , wherein the hole transport layer is at least one selected from the group consisting of: polythiophene and derivatives thereof; aromatic amine compounds; polymer compounds comprising a structural unit comprising an aromatic amine residue; CuSCN; CuI; NiO; WO 3 ; and MoO 3 .
22. The photoelectric conversion element according to claim 1 , wherein the hole transport material has a HOMO having a value in the range of −4.0 eV to −6.0 eV.