Note: Influence of calcium corrosion on the performance of an adjacent permeation barrier

Organic devices have to be protected with a permeation barrier against ambient moisture since their performance is strongly reduced by contact with water. The corrosion of calcium is widely used to evaluate such permeation barriers. However, design details of the calcium corrosion test may have severe consequences for the validity and precision of the measurement results. In this work, we present such a measurement distortion caused by the direct contact between calcium and the inorganic permeation barrier. Fortunately, even a 20 nm thin interlayer of a soft material (i.e., C60) sandwiched between calcium and the barrier reestablishes the validity of the measurement. In addition, we present our latest and improved electrical calcium test layout used for this investigation.