Photoelectrochemical reaction device

A photoelectrochemical reaction device, comprising:

• a first stack comprising a first electrode, a second electrode, and a photovoltaic layer provided between the first electrode and the second electrode;
• a second stack comprising a third electrode having ion permeability, a fourth electrode having ion permeability, and an ion migration layer provided between the third electrode and the fourth electrode, one of the third and fourth electrodes causing an oxidation reaction and the other of the third and fourth electrodes causing a reduction reaction;
• a first connecting member electrically connecting the first electrode and the third electrode;
• a second connecting member electrically connecting the second electrode and the fourth electrode;
• and
• an electrolytic solution tank including a first storage part to store a first electrolytic solution in which the first and third electrodes are immersed and a second storage part to store a second electrolytic solution in which the second and fourth electrodes are immersed,
• wherein an area of the second stack is larger than that of the first stack.