3 years ago

First-Principles Prediction of a Stable Hexagonal Phase of CH3NH3PbI3

First-Principles Prediction of a Stable Hexagonal Phase of CH3NH3PbI3
Xing Huang, Arashdeep Singh Thind, Rohan Mishra, Jianwei Sun
Methylammonium lead iodide (CH3NH3PbI3 or MAPbI3) perovskite is a promising new photovoltaic material with high power conversion efficiency. However, its perovskite phase with corner-connected PbI6 octahedra shows poor environmental stability. More recently, MAPbI3 has been shown to be thermodynamically unstable with a positive formation enthalpy. Here, using first-principles density functional theory calculations, we predict a layered hexagonal phase of MAPbI3 consisting of infinite chains of face-shared PbI6 octahedra with P63mc space-group symmetry to be thermodynamically the most stable phase for a wide range of volume and temperature compared to any of the experimentally observed perovskite phases with a different tilt pattern of the corner-connected octahedra. The predicted hexagonal phase is also dynamically stable without any soft phonon modes. The change from corner to face-shared connectivity in the hexagonal phase leads to a predicted band gap of 2.6 eV and a band structure that favors highly anisotropic charge transport.

Publisher URL: http://dx.doi.org/10.1021/acs.chemmater.7b01781

DOI: 10.1021/acs.chemmater.7b01781

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.