Dresden 2020 – wissenschaftliches Programm
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HL 76.16: Poster
Donnerstag, 19. März 2020, 15:00–17:30, P2/4OG
Analysis of semitransparent top contact induced Voc losses and their influences on long term stability in tandem solar cells — •Bor Li, Amran Al-Ashouri, Marko Jošt, Eike Köhnen, Marlene Härtel, Hans Köbler, and Steve Albrecht — HZB, Berlin, Germany
Semitransparent top contact layers are a key element for high efficiency perovskite based tandem solar cells. In addition, these layers, namely atomic layer deposited (ALD) tin oxide (SnO2) and sputtered indium zinc oxide (IZO) protect the perovskite solar cells against decomposition reactions in humid air and at high temperature, thus improving long term stability. However, they often induce fill factor (FF) and open circuit voltage (Voc) losses due to e.g. improper energetic alignment and/or defect generation during deposition. In this work, these effects are quantified and it is shown how Voc losses can be mitigated by using different additives and ultrathin interlayers between the perovskite absorber and the n-type top contact. By introducing modifications such as LiF interlayer or phenyl ethylammonium iodide (PEAI) additive, the non-radiative recombination losses can be reduced. This is proven by an increased steady-state photoluminescence yield and improvements in Voc. The successful absorber and interface modifications, together with the evaluation of stability and efficiency enhancement, were integrated into monolithic perovskite/silicon tandem solar cells. These modifications aim to increase the performance and stability of perovskite solar cell structures and to get one step closer towards commercial availability of this tandem solar cell technology.