TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Method: The method of forming the solar cell further comprises: electrically connecting the photosensitive electrode to a counter electrode; filling the nanotubes of the nanostructure membrane with photosensitive dye and placing electrolyte between the photosensitive electrode and the counter electrode to create a solar cell, where the filling step further comprises illuminating the solar cell, in which the counter electrode is illuminated; and immersing the nanostructure membrane in a titanium tetrachloride solution to form titanium dioxide nanoparticles in the nanotubes of the membrane. In the method of forming solar cell, the nanostructure membrane is attached to the transparent substrate using titanium isopropoxide or titanium alkoxide. Preferred Components: The transparent substrate comprises fluorine doped tin oxide glass. The counter electrode: is transparent; and comprises platinum on fluorine doped tin oxide glass.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The method of forming the nanostructure membrane further comprises: ultrasonicating the substrate during anodization, where anodization is carried out using a platinum cathode at a potential of 80 V; and opening the ends of titanium dioxide nanotubes array of the nanostructure membrane on the side formerly attached to the substrate, where the opening comprises contacting the side of the nanostructure membrane formerly attached to the substrate with an etchant. Preferred Components: The fluoride compound is ammonium fluoride (preferred), hydrogen fluoride or alkali fluoride. At least one nanotube in the nanostructure membrane: is substantially hexagonal along its length; and has a pore diameter of at least 180 nm.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The polar organic solvent comprises an alkylene glycol including ethylene glycol. The complexing agent comprises a polyamino carboxylic acid, preferably disodium dihydrogen EDTA. EXAMPLE - Titanium foils were cut into the desired size and shape, cleaned in acetone, dried and then processed for anodization. The anodization was carried out using ultrasonic waves (100 W and 42 kHz) by immersing a part of the titanium foil in the electrolytic solution (1000 ml). Water (5 vol.%), 0.5 M ammonium fluoride, 0.25 M disodium dihydrogen EDTA and ethylene glycol were mixed together thoroughly and used as the electrolytic solution (pH = 6.4-6.5). Titanium foil used as anode and platinum as cathode. The anodization was carried out for one hour at an applied potential of 80 V using a rectifier. The anodized samples were washed with distilled water to remove the occluded ions, dried in an air oven, and processed for further experiments and studies. The titanium dioxide nanotubes were annealed under oxygen atmosphere in a chemical vapor deposition furnace at 500 degrees C for 6 hours to yield crystalline titanium dioxide nanotubes. The anodized titanium dioxide nanotubes were detached from the metallic titanium substrate by keeping the templates at room temperature, thus the array was detached from the substrate on its own. The separation process can be sped up by heating the nanotube/substrate structure e.g. by using a hot air gun. The detached titanium dioxide nanotube membrane was etched with a solution of 5% aqueous hydrofluoric acid from the back side, thus dissolving the bather layer to obtain the titanium dioxide nanotube membrane comprising nanotubes with both ends open.