Chlorine Incorporation in the CH3NH3PbI3Perovskite: Small Concentration, Big Effect.
The role of chlorine doping in CH3NH3PbI3represents an important open issue in the use of hybrid perovskites for photovoltaic applications. In particular, even if a positive role of chlorine doping on perovskite film formation and on material morphology has been demonstrated, an inherent positive effect on the electronic and photovoltaic properties cannot be excluded. Here we carried out periodic density functional theory and Car-Parrinello molecular dynamics simulations, going down to ∼1% doping, to investigate the effect of chlorine on CH3NH3PbI3. We found that such a small doping has important effects on the dynamics of the crystalline structure, both with respect to the inorganic framework and with respect to the cation libration motion. Together, we observe a dynamic spatial localization of the valence and conduction states in separated spatial material regions, which takes place in the 10-1ps time scale and which could be the key to ease of exciton dissociation and, likely, to small charge recombination in hybrid perovskites. Moreover, such localization is enhanced by chlorine doping, demonstrating an inherent positive role of chlorine doping on the electronic properties of this class of materials.
Computational Laboratory for Hybrid/Organic Photovoltaics, CNR-ISTM , via Elce di Sotto 8, I-06123 Perugia, Italy.
Claudio
C
Quarti
Computational Laboratory for Hybrid/Organic Photovoltaics, CNR-ISTM , via Elce di Sotto 8, I-06123 Perugia, Italy.|CompuNet, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
Edoardo
E
Mosconi
Dipartimento di Fisica e Astronomia, Università di Padova , via Marzolo 8, I-35131 Padova, Italy.|Theory@Elettra Group, c/o Sincrotrone Trieste, Area Science Park, CNR-IOM DEMOCRITOS , I-34012 Basovizza, Trieste, Italy.
Paolo
P
Umari
Computational Laboratory for Hybrid/Organic Photovoltaics, CNR-ISTM , via Elce di Sotto 8, I-06123 Perugia, Italy.|CompuNet, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
Filippo
F
De Angelis