Dresden 2017 – wissenschaftliches Programm
CPP 13.32: Poster
Montag, 20. März 2017, 18:30–21:00, P1A
Mobility measurement in organic materials with TOF at cells using perovskite as charge generation layer — •Markus Feuerstein, John Love, Christian Wolf, and Dieter Neher — University of Potsdam
Charge carrier mobility is one of the most important parameters in organic solar cells. There are different methods to measure this value, but all of them carry some drawbacks. To determine the charge carrier mobility of organic materials, Time of Flight (TOF) is an established method. However it is limited to micron thick samples and therefore is not applicable in device relevant films. Compared to the standard method, in this work a perovskite charge generation layer (CGL) is put in front of the organic. Lead halide perovskites are a near ideal CGL as they have high light absorption properties, high charge carrier mobilities and appropriate energy levels for organic semiconductors. The vast majority of charges are created in the perovskite layer. The charge carriers are injected into the organic as a thin sheet and therefore sharpen the transients in the TOF measurements. With this method it is possible to measure mobility with all the advantages of normal TOF, but with much thinner organic layers and higher precision. We demonstrate the ability to fully characterize carrier mobility, varying temperature, thickness, field and donor:acceptor composition of soalr cell films, with a single technique. Finally, we demonstrate the importance of mobility and efficient charge transport in the organic layers of lead halide perovskite solar cells.