Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 46: Poster Session IV
CPP 46.2: Poster
Mittwoch, 14. März 2018, 11:00–13:00, Poster A
Charge Injection from CH3NH3PbI3−xClx to Organic Semiconductors Detected With sub-ps Transient Absorption Spectroscopy — •Jonas Horn1, Iulia Minda2, Heinrich Schwoerer2, and Derck Schlettwein1 — 1Institute of Applied Physics, JLU Giessen, Germany — 2Laser Research Institute, Stellenbosch University, South Africa
Presently, inverted perovskite solar cells are heavily studied. The charge transfer processes between the perovskite layer and the charge extraction layers is one of the key factors in solar cell performance. In most of these architectures, a combination of PEDOT:PSS as transparent hole conductor and PCBM as n-type semiconductor is used. In this study, pump-probe absorption spectroscopy with femtosecond resolution is used to determine the injection time of photo-generated charge carriers from the perovskite to the PEDOT:PSS and PCBM layers. A characteristic signal was identified to be caused by holes injected into the PEDOT:PSS layer by comparing the transient signals of photo-excited perovskite films with and without PEDOT:PSS interface. This signal appears within the resolution of the measurement setup (<200 fs) proving ultrafast charge carrier injection. Changes in the transient signals characteristic for the perovskite layer as reflected in the time constants obtained by global analysis confirmed this observation. We could also show ultrafast as well as slow injection of electrons into PCBM based on the decay of signals characteristic for the excited state of the perovskite as well as the appearance of characteristic PCBM signals.