NOVELTY - Production of zinc oxide acicular structure involves: holding a substrate in an electrolytic solution; and forming zinc oxide on the substrate by electrodeposition. The electrolytic solution comprises zinc ions and at least one cosolute.    USE - For production of zinc oxide acicular structure, useful in e.g. a cell and photoelectric conversion device (claimed). Also useful in pigments, coating materials, printing inks, cosmetics, pharmaceuticals, dental materials, electrophotographic photosensitive agents, semiconductor lasers, UV-screening agents, photocatalysts, sensors, surface elastic-wave filters and camera exposure materials.    ADVANTAGE - The use of the cosolute results in the zinc oxide acicular structure with a higher aspect ratio by controlling the growth of zinc oxide at the a,b-planes (in the direction horizontal to the substrate) and accelerating the growth at the c-plane (in the direction vertical to the substrate), by controlling various parameters such as, viscosity and surface tension of the electrolytic solution, inhibition of the formation of films in the zinc oxide acicular structures, controlling the adherence of the crystals to the substrate and its growth rate, maintaining the slender diameter of the crystals. The acicular crystals formed by the method have an aspect ratio of (5 - at least10, preferably at least100), minimum length of the lien passing the center of gravity of the cross section of the crystals of (at most500, preferably at most10, especially at most50) nm, and axial direction at an angle of (60 - 90, preferably 80 - 90)degrees to the plane of the substrate. The crystals are formed in a direction vertical to the substrate, rather than in a state in which they overlap in parallel to the substrate, and are joined to the substrate at their starting ends. The electrodeposition method reduces the problem of uniformity of the crystal structure with the use of large size electrodeposition system and substrate, as compared to the chemical vapor deposition (CVD) and physical vapor deposition (PVD) methods of the prior art, and avoids the monitoring of the associated parameters such as types of gases to be mixed, pressure, heating of sources or substrates at higher temperature, and thus the necessity of the usage of the large-scale production system, and the higher cost at the time of mass production; while controlling the cost. The usage of the crystals in the photoelectric conversion device reduces the probability of scattering of the electrons or holes produced by the light excitation, before they move to the collector electrode, and also eliminates the influence of grain boundaries in the movement of the elections, as compared to the Gratzel cells including the TiO2 particle crystal layer.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a cell comprising an electrode that comprises the zinc oxide acicular structure; and    (2) a photoelectric conversion device comprising an electron acceptor type charge transporting layer that comprises a zinc oxide acicular structure, an electron donor type charge transporting layer, and a light-absorbing between the charge transporting layer. The zinc oxide acicular structure is formed by electrodeposition on a conductive substrate in an electrolytic solution in which zinc ions and at least one cosolute are present.