News

CEST submitted new article on hybrid perovskites

Jingrui Li, Jari Järvi and Patrick Rinke develop the "pair mode" concept to describe the local structures of hybrid perovskites.
pair-mode_news_en.png

Our paper entitled "Pair modes of organic cations in hybrid perovskites: Insight from first-principles calculations of supercell models" is submitted to Physical Review B. It is available in arXiv (arXiv:1703.10464).

The disordered structures in hybrid perovskites, e.g., in the prototype material methylammonium lead triiodide (MAPbI3), are crucial to the materials properties that are closely relevant to the photovoltaic applications. Theoretical modelling of the orientational disorder of the organic methylammonium (MA) ions in MAPbI3 is very challenging, since large model systems and many samples are required to mimic the many possibilities of disordered structures. Density-functional theory (DFT), the most computationally efficient first-principles technique today, scales cubically with the system size and becomes very demanding for large MAPbI3 supercell models.

We introduce the concept of MA "pair modes", i.e., characteristic relative orientations of two neighboring MA ions. Our DFT results of small MAPbI3 supercell models indicate that system properties, such as total energy, band gap and band structure, strongly depend on the associated pair modes. For larger supercell models with disordered MAs, our DFT calculations result in a pair-mode distribution. This distribution reveals the origin of formation of the preferential local structures in MAPbI3.

Our pair-mode concept and large-supercell-model study provide combined atomistic-statistical insight to understand the disordered structures in bulk hybrid perovskite materials. It enables our upcoming multiscale modelling of large MAPbI3 systems to study realistic hybrid perovskites under realistic conditions.

  • Published:
  • Updated:
Share
URL copied!

Related news

taidemaalauksesta poimittu yksityiskohta ihmisen silmästä on rajattu ympyräksi oranssilla pohjalla
Research & Art Published:

Towards interfaces that distinguish user’s visual attention

Dissertation of the Month: What if interfaces we use are able to distinguish whether we are looking at them or not, and change their behavior accordingly?
Korkealta (Hotelli Clarionista) otettu maisemakuva Helsingin Hietalahdesta, etualalla merta
Research & Art Published:

Argumenta project for the professorship of history of architecture and architectural conservation

The project aims at deepening and increasing public discussion and societal impact on the fate of the modern building stock.
Urs Dieker working with wood, kuva Eren Öztekin
Research & Art Published:

Hollywood costume design goes sustainable

A textile artist sees natural materials as the future for costumes in television and film.
Kuva: Eeva Suorlahti
Research & Art Published:

Nordic project to enhance circularity of textiles

Doubling the life of textiles will reduce the climate impact by 40-50%. Still most of the used textiles generated in the Nordic region is incinerated instead of being reused, remanufactured and recycled. To enhance circularity of textiles a two-year Nordic project has been initiated.