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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: Perovskite and photovoltaics II (joint session HL/CPP)
CPP 33.5: Talk
Wednesday, March 29, 2023, 10:45–11:00, JAN 0027
NiO in perovskite solar cells: a peculiar interplay of degradation, passivation and device performance — •John Mohanraj1, Bipasa Samanta2, Maytal Caspary Torokar2, and Selina Olthof1 — 1University of Cologne, 50939 Cologne, Germany — 2Technion - IIT, Haifa, 3200003 Israel
The degradative interactions at the NiO/perovskite interface are notorious in the perovskite community as they lead to significant Voc and stability losses in p-i-n type perovskite solar cells (PSCs). So far, various Lewis bases have been introduced at this interface to passivate the metal oxide surface defects. Despite this process being successful in minimizing Voc and stability losses in PSCs, in-depth understanding of surface passivation and consequent suppression of the chemical processes at the NiO/perovskite interface are still elusive. This calls for a comprehensive surface investigation. To address these issues, we investigated solution processed NiO surfaces, their treatment with a series of passivating compounds, and the interface towards MAPbI3 in order to systematically probe the interface stability. Our methods include X-ray and UV photoelectron spectroscopy (XPS/UPS), XRD, SEM and UV-Vis absorption techniques. In parallel, first principle DFT calculations on differently treated NiO/MAPbI3 interfaces were carried out. These complementary investigations reveal changes in surface composition of the treated NiO and help us to suggest possible mechanisms for the degradative interactions. Finally, PSCs were fabricated using the stabilized NiO interfaces, and the impact on photovoltaic characteristics and device stability have been investigated.