TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation: Process for preparing doped titanium oxide (TiO2) particles with at least other metal component comprises:(i) preparing an aqueous titanium (Ti) salt solution and an aqueous dopant metal salt solution;(ii) combining a portion of the aqueous Ti salt solution with an aqueous basic solution containing at least 20% base while maintaining temperature at 50-95degreesC after rapid initial heating of reaction and dilution to yield a first mixture;(iii) combining the remaining aqueous Ti salt solution with the dopant metal salt solution to yield a second mixture; and(iv) precipitating doped metal oxide particles by combining the first and second mixture to reach a pH of 2-4.Preferred Use: Method of using TiO2 particles comprises:(a) applying a solution or paste having TiO2 particles onto an electrically conductive first substrate;(b) sintering the film to remove volatiles;(c) contacting the sintered film with a sensitizing dye to coat the TiO2 particles;(d) applying an electrically conductive second substrate material onto the side of the film opposite to the first substrate, so that TiO2 particles are positioned between the electrically conductive first and second substrates to form a cell;(e) drawing an electrolyte solution into the cell; and(f) sealing the cell.The particles have size of 0.1-10 mum and being aggregates of crystallites. The aggregates have open pore structure and the crystallites have size less than 100 x 10-9 m to form a thin film. SPECIFIC COMPOUNDS - The Ti salt is titanium tetrachloride (TiCl4). The base is ammonium hydroxide (NH4OH).    EXAMPLE - A 400 ml beaker was charged with ammonium hydroxide (NH4OH) (142 g) and chilled using an ice bath and stirred using Teflon coated paddle stir attached to a stirring to a stirring motor. A pump was used to delivery 195 g of TiCl4 to de-ionized water (DI H2O) at 15 cc/min to the rapidly stirring NH4OH. The end of the precipitation was 3 and the maximum temperature observed during the reaction was 60-65degreesC. The viscous slurry was filtered and washed with DI H2O (10 Li) to ionic conductance of 7 micro-ohms. The paste composed of 3 parts polymer solution to 1 part titanium dioxide was applied to substrates. The washed and filtered oxide was dried at 125degreesC and sintered at 550degreesC for 1 hour. A photovoltaic cell was constructed from these sintered samples. The efficiency was 3.5% at a light intensity of 25 mW/cm2 from a xenon.