@article{ErdilKhenkinRemecetal., author = {Erdil, Ulas and Khenkin, Mark and Remec, Marko and Emery, Quiterie and Sudhakar, Vediappan and Schlatmann, Rutger and Abate, Antonio and Katz, Eugene A. and Ulbrich, Carolin}, title = {Mimicking Outdoor Ion Migration in Perovskite Solar Cells: A Forward Bias, No-Light Accelerated Aging Approach}, series = {ACS Energy Letters}, volume = {10}, journal = {ACS Energy Letters}, number = {3}, publisher = {American Chemical Society}, issn = {2380-8195}, doi = {10.1021/acsenergylett.5c00376}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-20205}, pages = {1529 -- 1537}, abstract = {Perovskite solar cells (PSCs) are expected to transform the photovoltaic market; however, their unproven operational stability requires urgent attention, particularly accelerated aging tests. Currently, illumination is the primary stressor in such tests. In this work, we present an accelerated aging procedure consisting of prolonged forward biasing followed by a dark storage (postbias rest) phase, conducted entirely in the dark. During aging under forward bias, ion migration led to impeded charge transport, macroscopic defect growth, and an adverse response of the cells to short light soaking, all of which recovered in the postbias rest phase, yet resulted in increased recombination due to redistribution of ions. We found that outdoor operation of PSCs in Berlin, Germany, over a 20-month period exhibited similar dynamics, with periods of higher temperature and irradiance (spring-summer) aligning with the forward bias phase and cooler, dimmer periods (fall-winter) aligning with the postbias rest phase. This paves the way for accelerated aging tests that can mimic ion migration-induced degradation outdoors without requiring an illumination source.}, subject = {Perowskit}, language = {en} } @article{Farias‐BasultoKafedjiskaBertrametal., author = {Farias-Basulto, Guillermo and Kafedjiska, Ivona and Bertram, Tobias and Riedel, Maximilian and Emery, Quiterie and Remec, Marko and Graniero, Paolo and Khenkin, Mark and Kaufmann, Christian A. and Lauermann, Iver and Klenk, Reiner and Schlatmann, Rutger and Ulbrich, Carolin}, title = {Perovskite-CIGSe Tandem Solar Cell: Over One Year of Outdoor Monitoring}, series = {Advanced Energy and Sustainability Research}, volume = {6}, journal = {Advanced Energy and Sustainability Research}, number = {12}, issn = {2699-9412}, doi = {10.1002/aesr.202500162}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-22159}, pages = {11}, abstract = {Tandem solar cells can surpass the limitations of single-junction devices, promising increased performance due to lower thermalization losses. Even though many research and industrial upscaling efforts are based on perovskite-Si tandems, all-thin-film photovoltaic (PV) devices, for instance with chalcopyrite (CIGSe) and perovskite, can offer many advantages such as significant cost and material savings and access to niche markets like building integrated- and flexible PV. However, long-term stability and outdoor performance of perovskite-based tandem devices is to this day challenging. This work presents the first data analysis of year-round outdoor measurements (mpp-tracked) of a perovskite-chalcopyrite tandem device with a starting efficiency of about 23.14\% before encapsulation. The maximum outdoor performance of the tandem device changed during the period of observation, reaching the peak performance in April and then decreased due to the device degradation. At its maximum outdoor performance, the tandem could reach up to 68\% higher instantaneous power output, relative to its single-junction reference (CIGSe-SJ). In addition, a quantitative time series performance analysis, exemplary qualitative imaging characterization of the tandem before and after outdoor exposure, is shown. Finally, the possibility of predicting the immediate performance of an all-thin-film tandem is verified by using a multiple linear regression model with accuracies generally exceeding 90\%.}, subject = {Machine learning}, language = {en} }