Imaging device including photoelectric conversion layer

An imaging device comprising unit pixels, each unit pixel including:

• a photoelectric conversion unit including:
• a first electrode including a first conducting material,
• a second electrode facing the first electrode,
• a photoelectric conversion layer between the first and second electrodes, the photoelectric conversion layer including a first photoelectric conversion material, and
• a hole-blocking layer between the first electrode and the photoelectric conversion layer, the hole-blocking layer including a hole-blocking material;
• and
• a signal detection circuit electrically connected to the first electrode, wherein
• the hole-blocking material has an electron affinity lower than both a work function of the first conducting material and an electron affinity of the first photoelectric conversion material,
• the photoelectric conversion unit is adapted to be applied with a voltage between the first electrode and the second electrode, and the photoelectric conversion unit has a characteristic, responsive to the voltage within a range from a first voltage to a second voltage, showing that a density of current passing between the first electrode and the second electrode when light is incident on the photoelectric conversion layer becomes substantially equal to that when no light is incident on the photoelectric conversion layer, and
• a difference between the first voltage and the second voltage is 0.5 V or more.