NOVELTY - A photovoltaic cell (1) has a primary electrode (3), a secondary electrode (5) and a photovoltaic material (7) containing semiconductor nanocrystals. The semiconductor nanocrystals contain nanocrystals having a band gap smaller than peak solar radiation energy, or semiconductor nanocrystals differing in band gap energy. The width of photovoltaic material in direction from primary electrode to secondary electrode is less than 200 nm. The height of the photovoltaic material in direction perpendicular to width of photovoltaic material is 1 micron or more.    USE - Photovoltaic cell.    ADVANTAGE - The photovoltaic cell exhibits favorable exciton effect.    DETAILED DESCRIPTION - A photovoltaic cell has a primary electrode (3), a secondary electrode (5) and a photovoltaic material (7) containing semiconductor nanocrystals located between and in electrical contact with electrodes. The semiconductor nanocrystals contain semiconductor nanocrystals having a band gap smaller than peak solar radiation energy, such that the photovoltaic material exhibits multiple exciton effect in response to irradiation by the solar radiation, or semiconductor nanocrystals differing in band gap energy. The width of the photovoltaic material in direction from primary electrode to secondary electrode is less than 200 nm. The height of the photovoltaic material in direction perpendicular to width of photovoltaic material is 1 micron or more. The primary electrode has nanorod having carbon nanotube or an electrically conductive nanowire. The nanocrystals are germanium, silicon-germanium, lead-selenium, lead-tellurium, tin-tellurium, tin-selenium, bismuth-tellurium, antimony-tellurium, lead sulfide, bismuth-selenium, indium-arsenic, indium-antimony, cadmium- tellurium, cadmium sulfide or cadmium-selenium. INDEPENDENT CLAIMS are included for the following:    (1) formation of photovoltaic cell; and    (2) operating method of photovoltaic cell.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic three-dimensional view of photovoltaic cell array.    Cell (1)    Electrodes (3,5)    Photovoltaic material (7)    Conductive substrate (15)    Electrical insulating layer (17)