Compounds for infrared light sensing devices, infrared light sensing devices, image sensors, and electronic devices including the same

An infrared light sensing device configured to sense light in an infrared wavelength region, the infrared light sensing device comprising:

• an upper electrode and a lower electrode facing each other;
• and
• an infrared light absorption layer between the upper electrode and the lower electrode, the infrared light absorption layer including a compound represented by Chemical Formula 1:
• wherein, in Chemical Formula 1,
• Y1 to Y6 are independently
• a substituted or unsubstituted pentagonal ring including one of O, S, and Se, or
• a fused ring of two or more substituted or unsubstituted pentagonal rings including one of O, S, and Se,
• k, l, m, and n are independently 0 or 1, and
• Ra and Rb are independently hydrogen or a monovalent organic group,
• wherein the compound has a maximum absorption wavelength (λmax) in a wavelength range of greater than or equal to about 700 nm and less than or equal to about 1,400 nm in a thin film state, provided that,
• when k, l, m, and n are all 0, Y2 and Y5 are independently represented by Chemical Formula 2 or Chemical Formula 3:
• wherein, in Chemical Formulae 2 and 3,
• X1 is O,
• X2 and X3 are independently O or Se,
• R1 to R4 are independently hydrogen or a monovalent organic group, and
• * is a linking point.