BEGIN:VCALENDAR VERSION:2.0 PRODID:Data::ICal 0.22 BEGIN:VEVENT DESCRIPTION:Depei Zhang\, UVA - Department of Physics\n\n
Arguably the biggest challenge of the high-efficiency perovskite solar cells\, such as CH3NH3PbI3 and CH(NH 2)2PbI3\, is their device instability.< span style="font-size:14.0pt"> A recent study of 2D perovskite compounds\, butylammonium meth ylammonium lead iodide perovskite\, [CH3(CH2)3NH3]2(CH< sub>3NH3)n-1PbnI3n+1\, p roposed a solution to this problem. This class of materials shows a maximu m photovoltaic efficiency of 12.52%\, without any obvious degradation over thousands of hours under standard light illumination and humidity test. < /span>This talk focuses on the study of tem perature-dependent crystal structures\, along with the photovoltaic proper ties of the 2D 1-layer (n = 1) perovskite material. We have performed elas tic and inelastic neutron scattering\, Raman scattering\, and photolumines cence measurements on a powder sample of the 1-layer system ([CH3(CH2)3NH3]2PbI4 ). Our analysis of the data illuminates the evolution of the lattice struc ture\, rotational and vibrational dynamics with temperature\, and their co nnection to the charge carrier lifetime of the solar cell will be discusse d.
\n DTSTART:20180419T150000Z LOCATION:Physics Building\, Room 313 SUMMARY:Crystal Structures and Photoluminescence of a Two-Dimensional Perov skite END:VEVENT END:VCALENDAR