title: Impact of a Mesoporous Titania-Perovskite Interface on the Performance of Hybrid Organic-Inorganic Perovskite Solar Cells.
abstract: We report on the optimization of the interfacial properties of titania in mesoscopic CH3NH3PbI3 solar cells. Modification of the mesoporous TiO2 film by TiCl4 treatment substantially reduced the surface traps, as is evident from the sharpness of the absorption edge with a significant reduction in Urbach energy (from 320 to 140 meV) determined from photothermal deflection spectroscopy, and led to an order of magnitude enhancement in the bulk electron mobility and corresponding decrease in the transport activation energy (from 170 to 90 meV) within a device. After optimization of the photoanode-perovskite interface using various sizes of TiO2 nanoparticles, the best photovoltaic efficiency of 16.3% was achieved with the mesoporous TiO2 composed of 36 nm sized nanoparticles. The improvement in device performance can be attributed to the enhanced charge collection efficiency that is driven by improved charge transport in the mesoporous TiO2 layer. Also, the decreased recombination at the TiO2-perovskite interface and better perovskite coverage play important roles.
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Abdi-Jalebi
authors.affiliation: Laboratory of Photonics and Interfaces, Swiss Federal Institute of Technology (EPFL) , Station 6, Lausanne, CH 1015, Switzerland.
authors.forename: M Ibrahim
authors.initials: MI
authors.lastname: Dar
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Aditya
authors.initials: A
authors.lastname: Sadhanala
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Satyaprasad P
authors.initials: SP
authors.lastname: Senanayak
authors.affiliation: Laboratory of Photonics and Interfaces, Swiss Federal Institute of Technology (EPFL) , Station 6, Lausanne, CH 1015, Switzerland.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Giordano
authors.affiliation: Laboratory of Photonics and Interfaces, Swiss Federal Institute of Technology (EPFL) , Station 6, Lausanne, CH 1015, Switzerland.
authors.forename: Shaik Mohammed
authors.initials: SM
authors.lastname: Zakeeruddin
authors.affiliation: Laboratory of Photonics and Interfaces, Swiss Federal Institute of Technology (EPFL) , Station 6, Lausanne, CH 1015, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend