Abstract

Perovskite solar cells (PSC) are a prospective contender for the next generation of space photovoltaic technology due to their high specific power potential and their extraordinary radiation tolerance. Yet, for a successful application, devices need to resist several sets of extremes in space. One particularly extreme of important Low-Earth Orbits atomic oxygen (AtOx), which is known to etch the PSC devices. In this work, we report the applicability of thermally evaporated 0.7µm silicon oxide (SiOx) encapsulation as an AtOx barrier for triple-cation PSC and to understand the AtOx-induced degradation mechanism of phenethylammonium iodide (PEAI)-passivated and non-passivated devices. To do this, we encapsulated the complete devices with a 0.7-μm-thick silicon oxide layer evaporated atop the metal contact and subjected to AtOx over different exposure times. We found that after a total exposure duration of 120 minutes, the SiOx-encapsulated cells maintained over 97% of their initial power conversion efficiency (PCE), regardless of the device type (passivated or non-passivated). Our maximal AtOx exposure degraded the average power conversion efficiency (PCE) of devices without barrier encapsulation by 35% and 38% (2D-PEAI-passivated). In non-passivated and unencapsulated devices, AtOx has no impact on the short-circuit current density (J_SC), but degrades the fill factor (FF) and open circuit voltage (V_OC). In PEAI-passivated devices, the J_SC additionally degrades by almost 35%. To disentangle damage mechanisms between passivated and non-passivated devices we apply injection-current-dependent electroluminescence (EL) and intensity-dependent photoluminescence quantum yield (IPLQY) measurements. These allow us to derive pseudo-JV curves that are independent of the parasitic resistance effect from damaged transport layers. We quantify an implied FF, that remains high at 86.4% and 86.2% for non-passivated and passivated devices, respectively after 60min AtOx exposure. Comparing these with the normal JV curves reveals that the perovskite layer doesn’t have a contribution to the AtOx-induced FF loss. Instead, inefficient charge extraction and mobile ions are the primary causes of AtOx-induced FF and Jsc losses in passivated devices, whereas carrier-lifetime and photoluminescence studies show that non-radiative recombination is the cause of FF losses in non-passivated cells.

Biruk Alebachew Seid^a, Sema Sarisözen^a, Francisco Peña-Camargo^a, Sercan Ozen^a, Emilio Gutierrez-Partida^a, Martin Stolterfoht^a, Dieter Neher^a, Felix Lang^a*

^a Institute of Physics and Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany

* Corresponding Author: Felix Lang; Email: felix.lang.1@uni-potsdam.de