FisMat2017 - Submission - View

Abstract's title: Temperature and water effects on the microstructure evolution of hybrid perovskites investigated by large scale molecular dynamics
Submitting author: Alessandro Mattoni
Affiliation: CNR IOM Cagliari
Affiliation Address: Dipartimento di Fisica, Cittadella Universitaria, Monserrato 09042 (CA), Italy
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Claudia Caddeo (CNR-IOM SLACS Cagliari, Monserrato (CA), 09042, Italy), Simone Meloni (Dept. of Mechanical and Aerospace Engineering, Università La Sapienza, via Eudossiana 18, 00184, Roma, Italy), 
Alessio Filippetti (Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria, I-09042 Monserrato (Ca), Italy )
Abstract

Hybrid perovskites have been the object of intense research in recent years due to the exceptional photovoltaic properties of methylammonium lead trihalide (MAPI) solar cells[1].  The large lead and halide ions are at the origin of the MAPI softness and the need of organic MA cations to meet the tolerance factor requirement of a stable perovskite structure[1]. In addition, the ionic character of the crystal favors the migration of ions (in particular iodines) with  effects on conductivity, mass transport[2] and unconventional  hysteretic  current-voltage transients. MAPI is accordingly a "dynamical hybrid crystal" in which finite-temperature dynamics, molecular entropy and defects-related phenomena are crucially important[4,5]. 

Here, we show that, despite the complexity of MAPI, their main properties are successfully reproduced by a simple classical interatomic potential (MYP)[1,3,6] and we review a number of recent applications related to molecular ordering[5],vibrational properties[4], point-defects diffusivity[2], thermal transport[7].

In particular, we discuss the possibility to extend the models to include the interactions of MAPI with water. It is possible in this way to study the fast degradation in  water and to rationalize the transition from a reversible transformation in presence of vapor to an irreversible dissociation into insoluble lead iodide and MAI in presence of liquid water[8]. 

 

 

References

  1. A. Mattoni, A. Filippetti, C Caddeo, J. Phys. Condens. Matter 2017, 29, 43001.
  2. P. Delugas, C. Caddeo, A. Filippetti, and A. Mattoni, J. Phys. Chem. Lett. (2016), 7, 2356.
  3. A. Mattoni, A. Filippetti, M.I. Saba, and P. Delugas, J. Phys. Chem. C (2015),119, 17421.
  4. A. Mattoni, A. Filippetti, M.I. Saba, C. Caddeo, and P. Delugas, J. Phys. Chem. Lett. (2016), 7, 529.
  5. M. I. Dar, G. Jacopin, S. Meloni, A. Mattoni, et al. Sci. Adv. (2016),  e1601156
  6. T . Hata, G.Giorgi, K. Yamashita, C. Caddeo, and A. Mattoni,  J. Phys. Chem. C (2017), 121, 3724.
  7. C. Caddeo, C. Melis, M.I. Saba, A. Filippetti, L. Colombo and A. Mattoni, Phys. Chem. Chem. Phys. (2016), 18, 24318–24324.
  8. C. Caddeo, M.I. Saba, S. Meloni, A. Filippetti, and A. Mattoni, submitted (2017)