Photoelectric conversion element and compound

A photoelectric conversion element, comprising:

• a first electrode;
• a hole transport layer;
• a photoelectric conversion layer;
• an electron transport layer;
• and
• a second electrode,
• wherein the first electrode, the hole transport layer, the photoelectric conversion layer, the electron transport layer, and the second electrode are laminated in this order,
• the photoelectric conversion layer has a perovskite structure,
• the hole transport layer has an ionization potential in a range from −5.4 eV to −5.7 eV, and
• the hole transport layer comprises at least one of a compound represented by the following formula (I) or a salt thereof:
• wherein in the formula (I),
• Ar1 has a structure with an aromatic ring and optionally contains a heteroatom among atoms constituting the aromatic ring,
• Ar1 optionally has a substituent other than -L1-X1,
• the -L1-X1 is one or more, and when two or more of -L1-X1s are present, -L1s optionally are identical to or different from each other and -X1s optionally are identical to or different from each other,
• L1s are each an atomic group or a covalent bond that bonds Ar1 and X1,
• X1s are each a group configured to transfer charges to and from the first electrode, and
• X1s are each a phosphonic acid group (—P═O(OH)2), a carboxy group (—COOH), a sulfo group (—SO3H), a boronic acid group (—B(OH)2), a trihalogenated silyl group (—SiX3), or a trialkoxysilyl group (—Si(OR)3, where X is a halo group, and R is an alkyl group,
• wherein X1 is bonded to the first electrode.