NOVELTY - Titanium dioxide nano particle (I) capped with a surface stabilizer represented by phenyl-phosphonic acid compounds (a), phenyl-acetic acid compounds (b) or phenyl-sulfonic acid compounds (c), is new.    USE - (I) is useful in titanium dioxide nano ink, which is useful for forming electrode pattern in a substrate, where the substrate is useful in a solar cell (all claimed). (I) is useful for coating an electrode of a dye-sensitized solar cell.    ADVANTAGE - The ink comprising (I) has strong dispersibility as to be applicable by inkjet printing and has adequate viscosity without requiring printing several times. The inkjet printing of the titanium dioxide nano ink enables printing of a minute electrode. (I) maximizes the efficiency of the solar cell by minimizing the occurrence of pattern cracking and maximizing the diffusion and transition of electrons produced by a photoelectric conversion. (I) provides good compatibility with an ink composition. (I) resolves the clogging problem since the capped surface stabilizer minimizes the cohesion and minimized surface tension on the nozzle. (I) lowers production cost of the solar cell due to the decreased ink consumption; and simplifies the process to prepare the solar cell.    DETAILED DESCRIPTION - Titanium dioxide nano particle (I) capped with a surface stabilizer represented by phenyl-phosphonic acid compounds of formula (a), phenyl-acetic acid compounds of formula (b) or phenyl-sulfonic acid compounds of formula (c), is new.    R1-R3 = H, 1-20C alkyl, 2-20C alkenyl, 2-20C alkynyl or 6-30C aryl.    INDEPENDENT CLAIMS are included for:    (1) a titanium dioxide nano ink comprising (I), a dispersant and a solvent;    (2) a substrate having an electrode pattern formed using the titanium dioxide nano ink;    (3) a solar cell comprising the substrate;    (4) the preparation of (I); and    (5) forming an electrode pattern, comprising applying the titanium dioxide nano ink on a substrate and sintering the substrate.