title: Method to protect charge recombination in the back-contact dye-sensitized solar cell.
abstract: We prepared a back-contact dye-sensitized solar cell and investigated effect of the sputter deposited thin TiO₂ film on the back-contact ITO electrode on photovoltaic property. The nanocrystalline TiO₂ layer with thickness of about 11 μm formed on a plain glass substrate in the back-contact structure showed higher optical transmittance than that formed on an ITO-coated glass substrate, which led to an improved photocurrent density by about 6.3%. However, photovoltage was found to decrease from 817 mV to 773 mV. The photovoltage recovered after deposition of a 35 nm-thick thin TiO₂ film on the surface of the back-contact ITO electrode. Little difference in time constant for electron transport was found for the back-contact ITO electrodes with and without the sputter deposited thin TiO₂ film. Whereas, time constant for charge recombination increased after introduction of the thin TiO₂ film, indicating that such a thin TiO₂ film protected back electron transfer, associated with the recovery of photovoltage. As the result of the improved photocurrent density without deterioration of photovoltage, the back-contact dye-sensitized solar cell exhibited 13.6% higher efficiency than the ITO-coated glass substrate-based dye-sensitized solar cell.
authors.affiliation: Solar Cell Center, Korea Institute of Science and Technology, Seoul, Korea.
authors.forename: Beomjin
authors.initials: B
authors.lastname: Yoo
authors.forename: Kang-Jin
authors.initials: KJ
authors.lastname: Kim
authors.forename: Doh-Kwon
authors.initials: DK
authors.lastname: Lee
authors.forename: Kyungkon
authors.initials: K
authors.lastname: Kim
authors.forename: Min Jae
authors.initials: MJ
authors.lastname: Ko
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Kim
authors.forename: Won Mok
authors.initials: WM
authors.lastname: Kim
authors.forename: Nam-Gyu
authors.initials: NG
authors.lastname: Park