News

CEST developed a multi-scale model for disordered hybrid perovskites

Jingrui Li, Jari Järvi and Patrick Rinke (CEST) publish a paper on Phys. Rev. B with the development of a multi-scale modeling scheme for the disordered structures in hybrid perovskites.

CEST's paper "Multi-scale model for disordered hybrid perovskites: the concept of organic cation pair modes" (by Jingrui Li, Jari Järvi and Patrick Rinke) is published on Phys. Rev. B 98 045201 (2018).

In this paper, we have studied the properties of the prototype hybrid organic-inorganic perovskite CH3NH3PbI3 using relativistic density functional theory (DFT). For our analysis we introduce the concept of CH3NH3+ "pair modes", that is, characteristic relative orientations of two neighboring CH3NH3+ cations. In our previous work [Phys. Rev. B 94, 045201 (2016)] we identified two preferential orientations that a single CH3NH3+ cation adopts in a unit cell. The total number of relevant pairs can be reduced from the resulting 196 combinations to only 25 by applying symmetry operations. DFT results of several 2×2×2 supercell models reveal the dependence of the total energy, band gap and band structure on the distribution of CH3NH3+ cations and the pair modes. We have then analyzed the pair-mode distribution of a series of 4×4×4 supercell models with disordered CH3NH3+ cations. Our results show that diagonally-oriented CH3NH3+ cations are rare in optimized CH3NH3PbI3 supercell structures. In the prevailing pair modes, the C-N bonds of the two neighboring CH3NH3+ cations are aligned approximately vertically. Furthermore, we fit the coefficients of a pair-mode expansion to our supercell DFT reference structures. The pair-mode model can then be used to quickly estimate the energies of disordered perovskite structures. Our pair-mode concept provides combined atomistic-statistical insight into disordered structures in bulk hybrid perovskite materials.

  • Published:
  • Updated:
Share
URL copied!

Related news

media lab demo day
Research & Art Published:

Xmas Demo Day 2019 in photos

Collection of photos from the last Demo Day organized on the 5th of December 2019.
arkkitehdit Philip Tidwell, Kristo Vesikansa ja Laura Berger seisovat katsoen kameraan
Appointments, Cooperation, Research & Art Published:

Finland’s exhibition in the Biennale Architettura 2020 honors the Finnish prefabricated wooden houses of the WWII era

The exhibition will be conceived and curated by three researchers and teachers at Aalto University.
Quantum Garden
Research & Art Published:

Making understanding quantum computers easier

IBM collaborates with Professor Sabrina Maniscalco and her group to develop new transformative tools for teaching and outreach about quantum technologies
Student exhibition is on display at the Singapore National Design Centre
Cooperation, Research & Art Published:

Food for thought – rethinking Singapore’s hawker centres

Singapore’s traditional open-air cooked food centres or hawker centres presented a perfect case to be explored jointly by the Singapore University of Technology and Design (SUTD) and Aalto University.