TY - JOUR T1 - Photoelectric Conversion Properties of Dye-Sensitized Solar Cells Using Dye-Dispersing Titania JF - Journal of Physical Chemistry C Y1 - 2012 A1 - Nishikiori, H. A1 - Uesugi, Y. A1 - Setiawan, R. A. A1 - Fujii, T. A1 - Qian, W. A1 - El-Sayed, M. A. AB - The time-resolved fluorescence and photoelectrochemical properties of dye-sensitized solar cells using crystalline titania electrodes coated with N3 dye-dispersing amorphous titania gel were investigated to clarify the influence of the dye titania interaction and electron transfer on their photoelectric conversion performance. The photocurrent quantum efficiency of the electrodes was remarkably increased by a steam treatment due to the crystallization and densification of the amorphous titania layer compared to that of the untreated electrode. The electron injection from the dye to the crystalline titania foundation via the steam-treated titania dispersing the dye was confirmed to be more efficient than that in the conventional electrodes. The dye-dispersing titania layer prevented interaction between the dye molecules and back electron transfer from the titania to the electrolyte. The charge separation and photoelectric conversion performance of the dye-sensitized solar cells were improved by forming the specific dye-dispersing titania layer. VL - 116 SN - 1932-7447 N1 - Times Cited: 1Nishikiori, Hiromasa Uesugi, Yohei Setiawan, Rudi Agus Fujii, Tsuneo Qian, Wei El-Sayed, Mostafa A. M3 - 10.1021/jp2094388 ER - TY - JOUR T1 - Influence of Steam Treatment on Dye-Titania Complex Formation and Photoelectric Conversion Property of Dye-Doped Titania Gel JF - Journal of Physical Chemistry C Y1 - 2011 A1 - Nishikiori, H. A1 - Uesugi, Y. A1 - Takami, S. A1 - Setiawan, R. A1 - Fujii, T. A1 - Qian, Wei A1 - El-Sayed, Mostafa A AB - Xanthene dye molecules form a chelate complex with the titanium species on the titania surface in dye-titania systems. The complex formation causes a fast electron injection into the titania conduction band. In this study, simple spectroscopic and photocurrent measurements of the xanthene dye-doped titania gels prepared by the sol-gel method were conducted in order to clarify the influence of a steam treatment on the dye-titania interaction and electron transfer. The photocurrent quantum efficiency of the fluorescein-doped electrode was remarkably increased by the steam treatment compared to that of the untreated electrode consisting of an amorphous titania gel. The photocurrent action spectrum was red-shifted, and the short circuit photocurrent and open circuit voltage values increased with the steam treatment time. The steam treatment promoted the dye-titania complex formation, a negative shift in the conduction band potential of the titania, and the electron injection from the dye to the titania. VL - 115 SN - 1932-7447 N1 - Nishikiori, Hiromasa Uesugi, Yohei Takami, Shohei Setiawan, RudiAgus Fujii, Tsuneo Qian, Wei El-Sayed, Mostafa A. M3 - 10.1021/jp109958z ER - TY - JOUR T1 - Change in titania structure from amorphousness to crystalline increasing photoinduced electron-transfer rate in dye-titania system JF - Journal of Physical Chemistry C Y1 - 2007 A1 - Nishikiori, H. A1 - Qian, Wei A1 - El-Sayed, Mostafa A A1 - Tanaka, N. A1 - Fujii, T. AB - Thin titania gel films containing well-dispersed fluorescein dye were prepared by the sol-gel method and treated with steam to promote crystal growth of the titania particles. It is known that steam treatment converts the titania structure from amorphousness to crystalline. In the present study, such change is found to increase the rate of the photoinduced electron transfer from and to dispersed fluorescein dye molecules. VL - 111 SN - 1932-7447 N1 - Nishikiori, Hiromasa Qian, Wei El-Sayed, Mostafa A. Tanaka, Nobuaki Fujii, Tsuneo M3 - 10.1021/jp072625q ER -