engleski

Development of Single Junction Cell Amorphous Silicon Solar Photovoltaic Modules With Improved Resistance to Degradation

Several manufacturing technologies have been tried in a systematic study in order to decrease the overall photodegradation of large area P-I-N a-Si solar photovoltaic modules exposed to long-term outdoor conditions. The best results have been obtained for modules with very thin hydrogen-diluted i-layers grown at 140 degre C with graded dilution ratio. A persistent increase in the open-circuit voltage upon solar illumination has been explained by photoactivation of doping impurities in the p-layer of the p-i-n junction supported by hydrogen diffusion from the i-layer. The largest decrease in efficiencies comes from instability of the short.circuit current at the beginning of exposure to sunlight. For a specific manufacturing technology, in a single batch, the "inal" stabilized efficiency is directly proportional to the initial ,odule efficiency, and degradation fiffers only in changes of the fill factor. The effect is caused by differences in quality of the i-layer material depending on concebtration of dangling bpnds and impurities, and upon slight variations in the content of gases in a PECVD reactor.

p-i-n junction; a-Si; module; degradation

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