Solar cell and transparent electrode

1. A solar cell comprising:

a pair of electrodes; and

a photoelectric conversion layer of chalcopyrite structure sandwiched between the pair of electrodes, wherein

at least one of the pair of electrodes, adapted to serve as a transparent electrode, comprises a nitrogen-containing layer including an organic compound containing a nitrogen atom, and a metal layer containing a metal of Group 11 of the periodic table, the metal layer laminated on the nitrogen-containing layer.

2. The solar cell according to claim 1 , wherein the organic compound containing a nitrogen atom is an organic low molecular weight compound represented by the following general formula (1), a high molecular weight compound having a structural unit represented by the following general formula (2), or a high molecular weight compound having a structural unit represented by the following general formula (3):

wherein, in the general formula (1), A 1 represents a monovalent nitrogen atom-containing group, n1 represents an integer of 2 or more, and Y 1 represents an n1-valent organic group or single bond (—),

in the general formula (2), A 2 represents a divalent nitrogen atom-containing group, and Y 2 represents a divalent organic group or a single bond, and

in the general formula (3), A 3 represents a monovalent nitrogen atom-containing group, A 4 and A 5 each independently represent a divalent nitrogen atom-containing group, n2 represents an integer of 1 or more, n3 and n4 each independently represent an integer of 0 or 1, and Y 3 represents an (n2+2)-valent organic group.

3. The solar cell according to claim 2 , wherein any of A 1 in the general formula (1), A 2 in the general formula (2), and A 3 to A 5 in the general formula (3) contains a pyridine ring-containing group.

4. The solar cell according to claim 2 , wherein Y 1 in the general formula (1), Y 2 in the general formula (2) and Y 3 in the general formula (3) contain a group derived from a structure represented by the following general formula (4):

wherein, in the general formula (4),

Z represents —CR 1 R 2 —, —NR 3 —, —O—, —S—, or SiR 4 R 5 ,

X 1 to X 8 each independently represent —CR 6 ═ or —N═, and

R 1 to R 6 each independently represent a single bond (—), a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a substituted or unsubstituted alkyloxy group having 1 to 20 carbon atoms.

5. The solar cell according to claim 4 , wherein at least one of X 1 to X 8 in the general formula (4) contains a group having a nitrogen atom.

6. The solar cell according to claim 5 , wherein the metal layer contains silver as its most prevalent constituent.

7. The solar cell according to claim 6 , wherein the metal layer is 4 nm or more and 15 nm or less in film thickness.

8. The solar cell according to claim 7 , further comprising a high refractive index layer that is higher in refractive index than the nitrogen-containing layer.

9. The solar cell according to claim 8 , wherein the high refractive index layer is composed of a titanium oxide.

10. The solar cell according to claim 8 , wherein an antireflective layer with a refractive index of 1.5 or less is laminated on the high refractive index layer.

11. The solar cell according to claim 10 , wherein the antireflective layer is composed of a magnesium fluoride.

12. The solar cell according to claim 2 ,

wherein Y 1 in the general formula (1), Y 2 in the general formula (2) and Y 3 in the general formula (3) contain a group derived from a structure represented by the following general formula (4):

wherein, in the general formula (4),

Z represents —CR 1 R 2 —, —NR 3 —, —O—, —S—, or —SiR 4 R 5 ,

X 1 to X 8 each independently represent —CR 6 ═ or —N═, and

R 1 to R 6 each independently represent a single bond (—), a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a substituted or unsubstituted alkyloxy group having 1 to 20 carbon atoms.

13. The solar cell according to claim 12 , wherein at least one of X 1 to X 8 in the general formula (4) contains a group having a nitrogen atom.

14. The solar cell according to claim 1 , wherein the metal layer contains silver as its most prevalent constituent.

15. The solar cell according to claim 14 , wherein the organic compound containing the nitrogen atom is a compound in which an effective unshared electron pair content [n/M] meets 4.0×10 −3 ≦[n/M]≦4.0×10 −2 when n denotes the number of unshared electron pairs that are not involved in aromaticity or not coordinated to the metal among unshared electron pairs of nitrogen atoms, whereas M denotes a molecular weight.

16. The solar cell according to claim 14 , further comprising a high refractive index layer that is higher in refractive index than the nitrogen-containing layer.

17. The solar cell according to claim 1 , wherein the metal layer is 4 nm or more and 15 nm or less in film thickness.

18. The solar cell according to claim 1 , further comprising a high refractive index layer that is higher in refractive index than the nitrogen-containing layer.

19. The solar cell according to claim 1 , wherein the organic compound containing the nitrogen atom is a compound in which an effective unshared electron pair content [n/M] meets 4.0×10 −3 ≦[n/M]≦4.0×10 −2 when n denotes the number of unshared electron pairs that are not involved in aromaticity or not coordinated to the metal among unshared electron pairs of nitrogen atoms, whereas M denotes a molecular weight.