Understanding Performance and Stability of Perovskite-Based Tandems for Space Applications

All-perovskite tandem solar cells (2J-PSCs) combine two complementary band gaps to reduce thermalization losses and thus promise high power conversion efficiency (PCE). If fabricated on ultrathin substrates, they offer power-weight values beyond traditional space PV solutions. Yet there are still questions regarding their long-term stability outside Earth’s protective atmosphere where Atomic-Oxygen (AtOx), high-energetic radiation as well as extreme temperature cycles and low-intensity low-temperature (LILT) pose unconventional challenges.<br/><br/>In this presentation, I will discuss the extraordinary radiation tolerance of all-perovskite tandem solar cells and then move on to Atomic Oxygen degradation and their low-temperature, low-intensity behaviour. ^1–4 Atomic oxygen, unfortunately, corrodes unencapsulated PSCs swiftly, which in future has to be mitigated with ultralight barriers. Despite that, micrometeorites may cause an encapsulation failure, and therefore, we set out to understand the AtOx-induced degradation mechanisms of phenethylammonium iodide (PEAI)-2D passivated and non-passivated devices. Surprisingly, degradation is more severe in 2D passivated PSCs. Combining injection-current-dependent electroluminescence (EL), EL imaging and intensity-dependent photoluminescence quantum yield measurements (IPLQY) with resistance photovoltage transient measurements as well as grazing incidence wide angle X-Ray scattering (GIWAX) we find that 2D passivation layers are severely prone to accelerated degradation because of lateral diffusion of AtOx though the 2D surface owing to the large interplanar distance of 2D perovskites. This renders widely used 2D passivation’s problematic for space applications.⁵<br/><br/>We then tested un-passivated all-perovskite tandem solar cells for their performance under low-intensity low temperatures. This is interesting for outer planetary missions, e.g., to the vicinity of Saturn, where conditions feature a stark light intensity of 0.01AM0 with spacecraft temperatures hovering around ~120K. At these conditions, the tandem device drops to around 50%_rel of its initial performance, while control 1.5eV single junction solar cells retain their initial PCE without any loss. To enable a deeper understanding of the mechanisms behind these PCE losses, we then investigated the PCE, EL and PL of tandem solar cells and corresponding single junctions as a function of temperature. ⁸<br/><br/><b>References</b><br/><br/>Lang, F. Proton Radiation Tolerant All Perovskite Multijunction Solar Cells. Adv. Energy Mater. 2021, 11 (41), 2102246.<br/>Lang, F. Proton Radiation Hardness of Perovskite Tandem Photovoltaics. Joule 2020, 4 (5), 1054–1069.<br/>Lang, F. Efficient Minority Carrier Detrapping Mediating the Radiation Hardness of Triple-Cation Perovskite Solar Cells under Proton Irradiation. Energy Environ. Sci. 2019, 12 (5), 1634–1647.<br/>Lang, F. Radiation Hardness and Self Healing of Perovskite Solar Cells. Adv. Mater. 2016, 28 (39), 8726–8731.<br/>Seid, B. A. Understanding and Mitigating Atomic Oxygen Induced Degradation of Perovskite Solar Cells for Near Earth Space Applications. Small 2024.<br/>Thiesbrummel, J. Understanding and Minimizing VOC Losses in All-Perovskite Tandem Photovoltaics. ARXIV, 2022.<br/>Ozen, S. All-perovskite perovskite tandems in low-temperature, low-intensity outer planetary environments. Submitted.