title: Effect of Perovskite Overlayers on TiO2 Electrodes in Perovskite-Sensitized Solar Cells.
abstract: In this paper, we have studied the effect of the thickness of a CH3NH3PbI3 perovskite overlayer on mesoporous TiO2 electrodes in perovskite solar cells. The overlayers were prepared by spin coating PbI2 films on the electrodes, which were subsequently exposed to a CH3NH3I/2-propanol solution. We controlled the thickness of the perovskite overlayer by changing the PbI2 solution concentration. The thicknesses of the overlayers spin-coated from 0.5, 0.75, 0.9, and 1 M PbI2 solutions were approximately 179, 262, 316, and 341 nm, respectively. Perovskite solar cells with an approximately 316-nm-thick overlayer showed the highest efficiency of 9.11%. We conclude that optimization of the perovskite overlayer thickness in the solar cell structure is necessary to improve the cell efficiency.
authors.forename: Kang-Pil
authors.initials: KP
authors.lastname: Kim
authors.forename: Jeong-Hwa
authors.initials: JH
authors.lastname: Kim
authors.forename: Dae-Kue
authors.initials: DK
authors.lastname: Hwang