The invention relates to an image sensor comprising a plurality of pixels operatively connected to a control unit that includes a readout circuit, characterized in that it comprises a monolithic three-dimensional integrated circuit comprising an upper level and a lower level; wherein each pixel comprises: a photosensitive element arranged in said upper level and comprising a photosensitizing layer associated to a transport layer; an active device arranged in said lower level and operatively coupled to the photosensitive element; and a first intermediate terminal and an output terminal circuitally connected, respectively, to the photosensitive element and to the readout circuit; wherein the image sensor further comprises a dark current suppressing circuit; and wherein the control unit is configured to, upon readout of a pixel, circuitally connect the first intermediate terminal of said pixel with its output terminal through the dark current suppressing circuit. The invention also relates to an optoelectronic system comprising said image sensor and to a method of manufacturing said image sensor.