Characterization of polymer solar cells by TOF-SIMS depth profiling

Abstract Solar cells consisting of polymer layers sandwiched between a transparent electrode on glass and a metal top electrode are studied using dynamic time-of-flight secondary ion mass spectrometry (TOF-SIMS) in dual-beam mode. Because depth profiling of polymers and polymer–metal stacks is a relatively new field the craters were thoroughly investigated by environmental SEM (ESEM), interferometry, surface profilometry and tapping mode AFM. A huge increase in crater bottom roughness was observed when starting from the aluminum top layer going in depth, resulting in a loss of depth resolution. It is shown that layer-to-layer diffusion and contaminants at buried interfaces can be extracted from the depth profiles when taking into account the loss of depth resolution.