Staebler-Wronski effect
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GC: n

CT: Discovered in 1977 by David L. Staebler and Christopher R. Wronski, the Staebler-Wronski effect was described as a significant decrease in dark conductivity and photoconductivity as a result of
prolonged light soaking (LS) of a-Si:H material.

S: http://repository.tudelft.nl/assets/uuid:919fdef7-e5b2-467c-9b9d-2ee9fd55570a/Master_Thesis_Kim_Solesvik_Oppedal.pdf (last access: 13 February 2015)

N: 1. The degradation of electrical output of hydrogenated amorphous silicon solar cells as a result of prolonged illumination.
2. For twenty years we searched to understand the Staebler-Wronski effect (SWE). New results continue to emerge which invalidate prior interpretations. Recent evidence shows that the SWE is not associated with impurities. Long-range hydrogen diffusion is ruled out because the SWE occurs with comparable efficiency between 400K and the lowest temperatures. Nonradiative geminate recombinations might be important since high fields reduce the SWE significantly. It disappears when the bandgap or the photon energy falls below a critical value. The creation of a metastable density of dangling bond defects has been considered to be its sole manifestation. However, there is mounting evidence for light-induced structural changes which extend throughout the material. The weak bond breaking model emerges as the only viable explanation of the SWE if the expected spatial correlation between defects and hydrogen is destroyed by subsequent recombination events. The SWE is reduced by a favorable microstructure and low hydrogen content. It is suggested that defect pairs have larger recombination coefficients than isolated defects.

S: 1. TERMIUMPLUS. 2. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8087693 (last access: 13 February 2015).

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CR: photovoltaic solar energy