Berlin 2018 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 72: Hybrid and Perovskite Photovoltaics I
CPP 72.4: Talk
Thursday, March 15, 2018, 16:00–16:15, C 264
In-Situ Investigation of Ion Migration and Aggregation in Organolead Halide Perovskite Films — •Yu Zhong1, Carlos Andres Melo Luna2, Richard Hildner2, Cheng Li1, and Sven Huettner1 — 1Macromolecular Chemistry I, University of Bayreuth, Bayreuth, Germany — 2Experimental Phyiscs IV, University of Bayreuth, Bayreuth, Germany
During current-voltage(J-V) measurements, perovskite solar cells(PSCs) exhibit a certain photo-induced instability and hysteresis phenomenon. Firstly, we study the light-induced behavior in CH3NH3PbI3-xClx film in-situ, by employing wide-field photoluminescence(PL) microscopy to obtain both the spatially- and temporally-resolved PL image. Along with the increase of the PL intensity under continuous illumination, some areas render PL inactive. A faster and more obvious PL decay process was observed with a higher excitation energy. By characterizing this excitation energy dependent PL decay, we suggest that the PL quenching can be ascribed to an aggregation of iodide ions. Secondly, by introducing phenyl-C61-butyric acid methyl ester(PCBM) in PSCs, hysteresis phenomenon is suppressed. The results of wide-field PL image and temperature dependent J-V curve measurement confirm that PCBM molecules decrease the mobility and increase the activation energy of iodide ions. This real-time investigation of the light soaking of perovskite films provides more details to improve the performance of PSCs. The suppression of the iodide ions movement, e.g. involving PCBM, is a concern for better performance and stability of PSCs.