Wydarzenia



Seminarium Instytutu Niskich Temperatur i Badań Strukturalnych PAN

12:00 Thursday, 25-02-21
Microsoft Teams

Excitons and Phonons in 2D perovskites

dr hab. Paulina Płochocka-Maude, prof. PWr

Narodowe Laboratorium Silnych Pól Magnetycznych (LCNMI CNRS) w Tuluzie we Francji; Wydział Podstawowych Problemów Techniki Politechniki Wrocławskiej

Seminarium odbędzie się w aplikacji Microsoft Teams (dla osób z domeny intibs.pl kod dostępu to: to8aqyj). Pozosotałe osoby zainteresowane seminarium proszone są o kontakt z dr. hab. Adamem Pikulem ().

The seminar will be held in the Microsoft Teams application (for people from the intibs.pl domain, the access code is: to8aqyj). Other people interested in the seminar are asked to contact dr. hab. Adam Pikul ().

Streszczenie:

High environmental stability and surprisingly high efficiency of solar cells based on 2D perovskites have renewed interest in these materials. These natural quantum wells consist of planes of metal-halide octahedra, separated by organic spacers.  Remarkably the organic spacers play crucial role in optoelectronic properties of these compounds. The characteristic for ionic crystal coupling of excitonic species to lattice vibration became particularly important in case of soft perovskite lattice. The nontrivial mutual dependencies between lattice dynamics, organic spacers and electronic excitation manifest in a complex absorption and emission spectrum which detailed origin is subject of ongoing controversy. First, I will discuss electronic properties of 2D perovskites with different thicknesses of the octahedral layers and two types of organic spacer.  I will demonstrate that the energy spacing of excitonic features depends on organic spacer but very weakly depends on octahedral layer thickness. This indicates the vibrionic progression 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 result, and unlike in any other semiconductor, the effective mass in 2D perovskites can be easily tailored.  

INSTYTUT NISKICH TEMPERATUR
I BADAŃ STRUKTURALNYCH
im. Włodzimierza Trzebiatowskiego
POLSKIEJ AKADEMII NAUK
Adres Instytutu:
ul. Okólna 2, 50-422 Wrocław
Adres elektroniczny:
71 343 5021, 71 395 4xxx (xxx nr wew.)
Fax: 71 344 1029
Poniedziałek - piątek w godz. 7:30-15:30