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

An organic photoelectric device, comprising:

• a first electrode and a second electrode facing each other, and
• an active layer between the first electrode and the second electrode, the active layer including a compound represented by Chemical Formula 1:
• wherein, in Chemical Formula 1,
• Ar is selected from a substituted or unsubstituted 5-membered aromatic ring, a substituted or unsubstituted 6-membered aromatic ring, and a condensed ring of two or more of the foregoing rings,
• X1 is Se,
• each of R1 to R3 are independently selected from hydrogen, 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 halogen, a cyano group (—CN), a cyano-containing group, and a combination thereof, and
• each of Ar1 and Ar2 are independently selected from a substituted or unsubstituted C6 to C30 aryl group, and a substituted or unsubstituted C3 to C30 heteroaryl group, provided that at least one of Ar1 and Ar2 is a heteroaryl group including at least one nitrogen (N) at an ortho position with respect to a linking group with the nitrogen (N).