Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 38: Fundamentals of Perovskite Photovoltaics V (joint session CPP/DS/HL)

CPP 38.3: Talk

Wednesday, March 22, 2017, 11:00–11:15, ZEU 250

Real-Time Observation of Iodide Ion Migration in Methylammonium Lead Halide Perovskites — •Cheng Li¹, Antonio Guerrero², Yu Zhong¹, Anna Gräser¹, Carlos Andres Melo Luna³, Jürgen Köhler³, Juan Bisquert², Richard Hildner³, and Sven Huettner¹ — ¹Macromolecular Chemistry I, Universität Bayreuth, Universitätstr. 30, 95447 Bayreuth, Germany — ²Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castell, Spain — ³Experimental Physics IV and Bayreuth Institute of Macromolecular Research, Universität Bayreuth, Universitätstr. 30, 95447 Bayreuth, Germany

To investigate the origin of current-voltage (J-V) hysteresis characteristic in perovskite solar cells (PSC), we utilize correlated time-resolved photoluminescence (PL) microscopy and impedance spectroscopy (IS) on perovskite films to in-situ investigate both the spatial and temporal evolution of these PL inactive areas under external optical/electrical fields. We attribute the formation of PL inactive domains to the migration and accumulation of iodine ions under external electrical fields. Furthermore, we fabricate and characterize PSC incorporating phenyl-C61-butyric acid methyl ester (PCBM) and PCBM polymer to investigate the influence of diffusions of PCBM molecules on the hysteretic behavior. Following that, the step-wise temperature dependent J-V measurement demonstrates the reduction of migration with the aid of PCBM molecules. Hence, it is proposed that the elimination/alleviation of J-V curve hysteresis is ascribed to the diffusion of PCBM molecules, which passivate the iodide related defects.