BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:IMX Seminar Series - Excitons and Phonons in 2D perovskites
DTSTART:20201102T131500
DTEND:20201102T141500
DTSTAMP:20260504T032528Z
UID:f3d55f69ca1714fddebdc3a9b4c0da93cc1cb90ef5c9f5ec743a7f40
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Paulina Plochocka\, CNRS Toulouse\, France\nHigh environ
 mental stability and surprisingly high efficiency of solar cells based on 
 2D perovskites have renewed interest in these materials. These natural qua
 ntum wells consist of planes of metal-halide octahedra\, separated by orga
 nic spacers.  Remarkably the organic spacers play crucial role in optoele
 ctronic properties of these compounds.The characteristic for ionic crystal
  coupling of excitonic species to lattice vibration became particularly im
 portant in case of soft perovskite lattice. The nontrivial mutual dependen
 cies between lattice dynamics\, organic spacers and electronic excitation 
 manifest in a complex absorption and emission spectrum which detailed orig
 in is subject of ongoing controversy. First\, I will discuss electronic pr
 operties of 2D perovskites with different thicknesses of the octahedral la
 yers and two types of organic spacer.  I will demonstrate that the energy
  spacing of excitonic features depends on organic spacer but very weakly d
 epends on octahedral layer thickness. This indicates the vibrionic progres
 sion scenario which is confirmed by high magnetic fields studies up to 67T
 . Finally\, I will show that in 2D perovskites\, the distortion imposed by
  the organic spacers governs the effective mass of the carriers.  As a re
 sult\, and unlike in any other semiconductor\, the effective mass in 2D pe
 rovskites can be easily tailored.  \n 
LOCATION:Zoom https://epfl.zoom.us/j/95940364570
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR