• Effect of humidity on the orientational ordering of CH$_3$NH$_3^+$ in methylammonium lead iodide

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      https://www.ias.ac.in/article/fulltext/boms/043/0304

    • Keywords

       

      CH$_3$NH$_3$PbI$_3$; phase transitions; ferroelectricity; humidity.

    • Abstract

       

      With high energy conversion efficiency and low-cost production, hybrid organic–inorganic perovskite solar cells (PSCs) have the potential to be alternative to silicon-based technology. However, there are concerns about their longterm stability and environmental friendliness, which must necessarily be addressed to enable large-scale commercialization of PSCs. Here, we use first-principles theory to determine and understand the effects of humidity on theT-dependent tetragonal to cubic structural transition in CH$_3$NH$_3$PbI$_3$, which can impact the long-term stability of its properties. We show that ferroelectric vs. antiferroelectric structural ordering in CH$_3$NH$_3$PbI$_3$ is influenced by humidity. Within first-principles density functional theory, we determine the lowest energy configurations of dipolar ordering in CH$_3$NH$_3$PbI$_3$$\cdot$$x$H$_2$O and effects of their interaction with H$_2$O molecules. Developing a simple effective Hamiltonian tomodel these configurations, we use Monte Carlo simulations to determine temperature-dependent structural phase transitions in CH$_3$NH$_3$PbI$_3$. We establish ferroelectric ordering in MAPbI$_3$ at low temperature, and demonstrate that it changes to antiferroelectric ordering of MA$^+$ cations at $x>0.2$ in CH$_3$NH$_3$PbI$_3$$\cdot$$x$H$_2$O.

    • Author Affiliations

       

      SHIVANI GROVER1 UMESH V WAGHMARE2

      1. Chemistry and Physics of Materials Unit, School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
      2. Theoretical Sciences Unit, School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
    • Dates

       
  • Bulletin of Materials Science | News

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