Photoelectric conversion element, measuring method of the same, solid-state imaging device, electronic device, and solar cell
The present technology relates to a photoelectric conversion element, a measuring method of the same, a solid-state imaging device, an electronic device, and a solar cell capable of further improving a quantum efficiency in a photoelectric conversion element using a photoelectric conversion layer including an organic semiconductor material. The photoelectric conversion element includes two electrodes forming a positive electrode ( 11 ) and a negative electrode ( 14 ), at least one charge blocking layer ( 13, 15 ) arranged between the two electrodes, and a photoelectric conversion layer ( 12 ) arranged between the two electrodes. The at least one charge blocking layer is an electron blocking layer ( 13 ) or a hole blocking layer ( 15 ), and a potential of the charge blocking layer is bent. The present technology is applied to, for example, a solid-state imaging device, a solar cell, and the like having a photoelectric conversion element.
1. A photoelectric conversion element, comprising:
a positive electrode;
a negative electrode;
at least one charge blocking layer arranged between the positive electrode and the negative electrode; and
a photoelectric conversion layer arranged between the positive electrode and the negative electrode, wherein
the at least one charge blocking layer is a hole blocking layer, positions X 1 ′, X 2 ′, and X 3 ′ are located at specific predetermined distances x 1 ′, x 2 ′, and x 3 ′, wherein x 1 ′, x 2 ′, and x 3 ′ satisfies a condition x 1 ′<x 2 ′<x 3 ′ from an interface between the hole blocking layer and the positive electrode toward the photoelectric conversion layer,
absolute values ΔE(X 1 ′), ΔE(X 2 ′), and ΔE(X 3 ′) of a difference between a work function WF of the positive electrode and an ionization potential Ip of the hole blocking layer at each position satisfy a following formula (2),
Δ E ( X 2′)>Δ E ( X 1′) and Δ E ( X 2′)>Δ E ( X 3′) (2)
the hole blocking layer comprises a first hole blocking layer and a second hole blocking layer, and
a donor impurity density of the first hole blocking layer is different from that of a donor impurity density of the second hole blocking layer.
2. The photoelectric conversion element according to claim 1 , wherein
the donor impurity density of the first hole blocking layer is one of equal to or higher than 1e16/cm3, and
the donor impurity density of the second hole blocking layer is lower than 1e16/cm3.
3. The photoelectric conversion element according to claim 2 , wherein
the first hole blocking layer has contact with the positive electrode, and
the second hole blocking layer has contact with the photoelectric conversion layer.
4. The photoelectric conversion element according to claim 2 , wherein
the first hole blocking layer has contact with the photoelectric conversion layer, and
the second hole blocking layer has contact with the positive electrode.