AFM Studies of Pristine PCBM Changes Under Light Exposure

Sammanfattning: Organic solar cells promise a cheap and easy alternative to silicon photovoltaics, but there are many problems that must be solved before they can be a stable and efficient substitute. One such problem is the degradation of solar cells under exposure to light and oxygen. In response to evidence of change in electronic properties of polymer:PCBM solar cells, the mechanical properties of pristine PCBM films are investigated for analogous development using atomic force microscopy. Although no signicant change in the elastic modulus is detected, differences in material response indicate a skin effect which is beyond measurement sensitivity. Presence of a hard skin is verified in tapping phase imaging and spectroscopy.