WEB Analyzing Interface Recombination in Lead-Halide Perovskite Solar Cells with Organic and Inorganic Hole-Transport LayersFriday (25.09.2020) 10:25 - 10:40 Z: Special Symposia I Part of:
The interfaces between absorber and transport layers have been shown to be critical for perovskite device performance. However, quantitative characterization of interface recombination has so far been proven to be highly challenging in working perovskite solar cells. Here we study methylammonium lead halide (CH3NH3PbI3) perovskite solar cells based on a range of different hole-transport layers, namely an inorganic hole-transport layer CuOx ,an organic hole transport layer PTAA, and a bilayer of CuOx/PTAA. The cells are completed by a PCBM/BCP/Ag electron contact. We characterize energy levels using photoelectron spectroscopy and recombination dynamics by combining steady-state photoluminescence and transient photoluminescence with numerical simulations. While the PTAA-based devices show hardly any interface recombination losses and open-circuit voltages > 1.2 V, we observe substantial losses for the samples with a direct CuOx/perovskite interface. We assign these losses to a combination of energetic misalignment at the CuOx/perovskite interface coupled with increased interface recombination velocities at the perovskite/PCBM interface.