An Interlaboratory Study on the Stability of All-Printable Hole Transport Material–Free Perovskite Solar Cells

Comparisons between different laboratories on long-term stability analyses of
perovskite solar cells (PSCs) is still lacking in the literature. This work presents the
results of an interlaboratory study conducted between five laboratories from four
countries. Carbon-based PSCs are prepared by screen printing, encapsulated, and
sent to different laboratories across Europe to assess their stability by the application
of three ISOS aging protocols: (a) in the dark (ISOS-D), (b) under simulated
sunlight (ISOS-L), and (c) outdoors (ISOS-O). Over 1000 h stability is reported for
devices in the dark, both at room temperature and at 65 C. Under continuous
illumination at open circuit, cells survive only for few hours, although they recover
after being stored in the dark. Better stability is observed for cells biased at
maximum power point under illumination. Finally, devices operate in outdoors for
30 days, with minor degradation, in two different locations (Barcelona, Spain and
Paola, Malta). The findings demonstrate that open-circuit conditions are too severe
for stability assessment and that the diurnal variation of the photovoltaic
parameters reveals performance to be strongly limited by the fill factor, in the
central hours of the day, due to the high series resistance of the carbon electrode.