title: Mixed-Halide CH3 NH3 PbI3-x Xx (X=Cl, Br, I) Perovskites: Vapor-Assisted Solution Deposition and Application as Solar Cell Absorbers.
abstract: There have been recent reports on the formation of single-halide perovskites, CH3 NH3 PbX3 (X=Cl, Br, I), by means of vapor-assisted solution processing. Herein, the successful formation of mixed-halide perovskites (CH3 NH3 PbI3-x Xx ) by means of a vapor-assisted solution method at ambient atmosphere is reported. The perovskite films are synthesized by exposing PbI2 film to CH3 NH3 X (X=I, Br, or Cl) vapor. The prepared perovskite films have uniform surfaces with good coverage, as confirmed by SEM images. The inclusion of chlorine and bromine into the structure leads to a lower temperature and shorter reaction time for optimum perovskite film formation. In the case of CH3 NH3 PbI3-x Clx , the optimum reaction temperature is reduced to 100 °C, and the resulting phases are CH3 NH3 PbI3 (with trace Cl) and CH3 NH3 PbCl3 with a ratio of about 2:1. In the case of CH3 NH3 PbI3-x Brx , single-phase CH3 NH3 PbI2 Br is formed in a considerably shorter reaction time than that of CH3 NH3 PbI3 . The mesostructured perovskite solar cells based on CH3 NH3 PbI3 films show the best optimal power conversion efficiency of 13.5 %, whereas for CH3 NH3 PbI3-x Clx and CH3 NH3 PbI3-x Brx the best recorded efficiencies are 11.6 and 10.5 %, respectively.
authors.affiliation: Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, 14588, Iran.
authors.forename: Rahime
authors.initials: R
authors.lastname: Sedighi
authors.affiliation: Department of Nanotechnology and Advanced Materials, Materials and Energy Research Center, Karaj, 31787-316, Iran. f.tajabadi@merc.ac.ir.
authors.forename: Fariba
authors.identifier: http://orcid.org/0000-0003-0121-8469
authors.initials: F
authors.lastname: Tajabadi
authors.affiliation: Chemistry Department, Iran University of Science and Technology, Tehran, 1684613114, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Shahbazi
authors.affiliation: Faculty of Physics & Chemistry, Alzahra University, Tehran, 1993893973, Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Gholipour
authors.affiliation: Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, 14588, Iran. taghavinia@sharif.edu.|Physics Department, Sharif University of Technology, Tehran, 14588, Iran. taghavinia@sharif.edu.
authors.forename: Nima
authors.initials: N
authors.lastname: Taghavinia
keywords: electrochemistry; perovskite phases; solar cells; thin films; vapor-assisted solution deposition