Poster: Degradation Mechanisms in Carbon Printed Perovskite Solar Cells

We present a comprehensive study of screen printed mesoporous MAPbI3 perovskite solar cells fabricated from commercially available substrates and precursors (Solaronix) in an ambient undergraduate laboratory. Cells are aged under a variety of conditions including in our laboratory under both Xenon (Sunlite) and LED (G2V) AM1.5G solar simulators, outdoors on a southern California rooftop mounted two axis solar tracker under spring and summer sun, at various temperatures, with variable UV exposure, and following a variety of different encapsulation processes. All cells are aged under maximum power point tracking conditions with commercial SMUs making periodic measurements (Infinity PV). Irradiance is measured with calibrated silicon reference cells and optical pyranometers. Beyond IV curves to extract electronic device parameters, cells are further characterized by a wide variety of methods at different points in the aging process. Spatial information is gathered from optical imaging, laser beam induced current mapping, electroluminescence and photoluminescence (BrightSpot), and IR thermography. The various spatial images provide complementary information helping to elucidate changes in the devices over time. In addition, we record spectral response via external quantum efficiency (Newport). We observe stable devices indoors both under constant illumination and can observe modest reversible degradation under indoor studies when illumination is cycled on and off following a daylight pattern. Outdoor time studies show a much larger range of behaviors including both chemical induced decomposition and UV induced degradation. In many cases the spatial nucleation sites of the degradation can be seen in the initial characterization long before cells are degraded. Most importantly, we also will present methods that achieve stable outdoor performance.