DPG Phi
Verhandlungen
Verhandlungen
DPG

Regensburg 2016 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 80: Hybrid and Perovskite Photovoltaics IV (Joint session of CPP, DF, DS and HL, organized by HL)

HL 80.9: Talk

Thursday, March 10, 2016, 17:15–17:30, H2

Dynamics and nature of photo-excited carriers in (CH3NH3)PbI3 organic-inorganic perovskite — •Daniel Niesner1,2, Haiming Zhu1, Tyler J. S. Evans1, Bryan J. Kudisch1, Prakriti P. Joshi1, Kiyoshi Miyata1, M. Tuan Trinh1, Manuel Marks1, and X.-Y. Zhu11Department of Chemistry, Columbia University, New York, NY 10027, USA — 2Festkörperphysik, FAU Erlangen-Nürnberg, D-91058 Erlangen, Germany

Thin film solar cells based on organic-inorganic perovskites are the rising star in photovoltaics. The photophysics and transport mechanism behind the outstanding device performance remain a matter of debate. I will present the results of a study on carrier dynamics in vapor-deposited thin films of (CH3NH3)PbI3, combining time-resolved two-photon photoemission, transient absorption, and photoluminescence.

After optical excitation with sufficient photon energy (≥ 2.15 eV), highly excited electrons relax quickly (≤ 0.3 ps) to a region of the conduction band with a low density of states, located 0.3 eV above the band minimum. In parallel, polaron formation takes place on a time scale of 0.28± 0.04 ps, matching the time scale of cation motion. Polaronic screening suppresses further energy relaxation and thermalization. The polaron maintains a significant excess energy for more than 60 ps.

The excess energy can be utilized to overcome energy barriers at grain boundaries and contacts. Harvesting it directly would result in a solar cell with an efficiency exceeding the Shockley-Queisser limit.

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2016 > Regensburg