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 comprises two electron blocking layers,
the two electron blocking layers comprise a first electron blocking layer and a second electron blocking layer,
an acceptor impurity density of the first electron blocking layer is different from an acceptor impurity density of the second electron blocking layer,
positions X1, X2, and X3 are located at specific distances x1, x2, and x3, wherein x1, x2, and x3 satisfy a condition x1<x2<x3 from an interface between the two electron blocking layers and the negative electrode toward the photoelectric conversion layer, and
absolute values ΔE(X1), ΔE(X2), and ΔE(X3) of a difference between an electron affinity Ea of the two electron blocking layers and a work function WF of the negative electrode at each position satisfy a following formula (1),
Δ E ( X 2)>Δ E ( X 1) and Δ E ( X 2)>Δ E ( X 3) (1).
2. The photoelectric conversion element according to claim 1 , wherein
the acceptor impurity density of the first electron blocking layer is equal to or higher than 1×10 16 /cm 3 , and
the acceptor impurity density of the second electron blocking layer is lower than 1×10 16 /cm 3 .
3. The photoelectric conversion element according to claim 2 , wherein
the first electron blocking layer is in contact with the negative electrode, and
the second electron blocking layer is in contact with the photoelectric conversion layer.
4. The photoelectric conversion element according to claim 2 , wherein
the first electron blocking layer is in contact with the photoelectric conversion layer, and
the second electron blocking layer is in contact with the negative electrode.
5. The photoelectric conversion element according to claim 1 , wherein
the at least one charge blocking layer further comprises a third electron blocking layer, and
an acceptor impurity density of the third electron blocking layer is lower than each of the acceptor impurity density of the first electron blocking layer and the acceptor impurity density of the second electron blocking layer.
6. The photoelectric conversion element according to claim 5 , wherein
the acceptor impurity density of the first electron blocking layer and the acceptor impurity density of the second electron blocking layer are each higher than 1×10 16 /cm 3 , and
the acceptor impurity density of the third electron blocking layer is lower than 1×10 16 /cm 3 .