Abstract
Highly efficient dye-sensitized solar cells become feasible using single crystalline anatase titania nanowires (TiNWs) and their network structures for semiconductor thin film instead of titania nanoparticles. We used laurylamine hydrocholoride(LAHC)/ tetraisopropylorthotitanate (TIPT) modified with acetylacetone (ACA) system. TIPT-ACA solution was mixed with 0.1 M LAHC aqueous solution at 313K, and the solution was stirred until the solution became transparent. Then, temperature was changed to 353K. After 96 h the solution became a white gel with a yellow liquid thin layer on the gel. Preparation of titania thin films was carried out as follows. We used gel samples before calcinations. Surfactant molecules in TiNWs can be removed by washing with alcohol. Standard Titania sample was prepared by mixing TiNWs with PEG(10%). Another samples were prepared by mixing TiNWs with both PEG(10%) and P-25(with various concentration). These samples were applied repetitivety to the conduction glass and distributed with a glass rod. Every time the sample was calcined at 723K for 30 min.
The photocurrent-voltage characteristics was measured using a potentiostat by irradiating with simulated solar light (bunko-keiki), i.e., AM1.5. IPCE (incident photon to conversion efficiency) was also measured. Titania particle P-25 was used as reference titania for comparison. We optimized the cell using various electrolyte. The conversion efficiency obtained by the six times repetitive coating resulted in over 8%. This data promise realization of highly efficiency dye-sensitized solar cells using TiNWs as semiconductor thin film through further improvement.
