Compound and photoelectric device, image sensor, and electronic device including the same

A compound represented by Chemical Formula 1:

• wherein, in Chemical Formula 1,
• Ar1 is a substituted or unsubstituted C6 to C30 arene group, a substituted or unsubstituted C3 to C30 heteroarene group, or a condensed ring thereof,
• X is O, S, Se, Te, S(═O), S(═O)2, NRa, SiRbRc, GeRdRe, or CRfRg, wherein Ra, Rb, Rc, Rd, Re, Rf, and Rg are independently hydrogen, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C6 to C10 aryl group, wherein Rb, Rc, Rd, Re, Rf, and Rg are independently present or at least one pair selected from Rb and Rc, Rd and Re, and Rf and Rg are linked to each other to form a spiro structure,
• Ar2 is a substituted or unsubstituted C6 to C30 hydrocarbon ring group having at least one functional group selected from C═O, C═S, C═Se, and C═Te, a substituted or unsubstituted C2 to C30 heterocyclic group having at least one functional group selected from C═O, C═S, C═Se, and C═Te, or a fused ring group thereof,
• R1 to R3 are independently hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, a pentafluorosulfanyl group (—SF5), a hydroxyl group, an amine group, a hydrazine group, a hydrazone group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, —SiRaRbRc, or a combination thereof, wherein Ra, Rb and Rc are independently hydrogen or a substituted or unsubstituted C1 to C10 alkyl group,
• R4 is hydrogen, deuterium, a halogen, a cyano group, a nitro group, a hydroxyl group, an amine group, a substituted or unsubstituted C1 to C10 alkyl group, or a substituted or unsubstituted C1 to C10 alkoxy group, and
• a is an integer of 0 to 4.