Energy production of single junction amorphous silicon modules with varying i-Layer thickness

The energy production of a number of single junction amorphous silicon (a-Si) solar modules with different intrinsic layer thicknesses is investigated. This has been carried out through both indoor measurement and real operating condition monitoring outdoors. After 13 months of light exposure, the fully degraded and seasonally annealed states, can be seen. The results indicate that the thinnest devices do not necessarily have the lowest degradation. The thicker devices which have higher initial efficiency, however do suffer greater efficiency degradation. Experiment also shows that energy production does not follow the initial Standard Test Condition (STC) rated efficiency as the highest can be seen in thinner modules, which initially have much lower efficiencies.