Disclosed are a photoelectronic device including a first electrode including a first metal; an active layer disposed between the first electrode and a second electrode; and a diffusion barrier layer disposed between the first electrode and the active layer; the diffusion barrier layer including a second metal, wherein the second metal has a thermal diffusivity that is lower than a thermal diffusivity of the first metal, and wherein the first electrode and the diffusion barrier layer are configured to transmit light, and an image sensor including the photoelectronic device.