Temperature-induced changes in the performance of amorphous silicon multi-junction modules in controlled light-soaking
✍ Scribed by Joseph A. del Cueto; Bolko von Roedern
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 241 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1062-7995
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✦ Synopsis
We extended our light-soaking tests of amorphous silicon (a-Si) modules, which were previously stabilized in light-soaking experiments conducted at 508C and 358C module temperatures for a combined total of 1840 h, to further light exposure at a lower temperature (258C). We de®nitively establish that changes in the exposure temperature signi®cantly modify module performance. Furthermore, we have determined that subsequent degradation observed upon light exposure at a lower temperature is completely recovered to start-of-test values within the accuracy of our measurements, as the operating temperature is increased again to 508C. The behavior is qualitatively similar in all modules tested, suggesting that the phenomena observed are governed by fundamental a-Si properties. This conduct is consistent with the annual variations observed for a-Si modules and systems deployed in the ®eld, at climates that undergo signi®cant temperature variations between winter and summer seasons. Because we have emulated the annual winter±summer oscillations twice, in a controlled-climate, light-soaking chamber and because module performance was always determined from simulator measurements performed at standard conditions, it is hard to defend the notion that the changes observed are either spectral or spectrally induced in nature.