Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 2: Hybrid and Perovskite Photovoltaics I
CPP 2.1: Hauptvortrag
Montag, 1. April 2019, 09:30–10:00, H18
The perovskite/transport layer interfaces dominate non-radiative recombination in efficient perovskite solar cells — •Martin Stolterfoht1, Pietro Caprioglio1, Christian Wolff1, Jose Marquez2, Thomas Kirchartz3, Thomas Unold2, and Dieter Neher1 — 1University of Potsdam — 2Helmholtz-Zentrum-Berlin — 3Forschungszentrum Jülich
Charge transport layers (CTLs) are key components of diffusion controlled perovskite solar cells, however they can induce additional non-radiative recombination pathways. By measuring the quasi-Fermi level splitting (QFLS) of perovskite/CTL heterojunctions, we quantify the interfacial recombination current for a wide range of commonly used CTLs, including various hole-transporting polymers, spiro-OMeTAD, metal oxides and fullerenes. We find that all studied CTLs limit the open-circuit voltage (Voc) by inducing a recombination current that is significantly larger than the loss in the neat perovskite and that the least-selective interface sets the upper limit for the device Voc. The results also show that the Voc equals the internal QFLS in the absorber layer of pin and nip-type cells with selective CTLs and power conversion efficiencies of up to 21.4% (in pin). However, in case of less selective CTLs, the Voc is substantially lower than the QFLS which indicates additional losses at the contacts and/or interfaces. The findings are corroborated by rigorous device simulations which outline several important considerations to maximize the Voc. This work shows that the real challenge to approach the radiative Voc limit lies in the suppression of carrier recombination at the perovskite/CTL interfaces.