Spectroscopic, scanning laser OBIC, and I-V/QE characterizations of browned EVA solar cells
- National Renewable Energy Lab., Golden, CO (United States). Center for Performance Engineering, Qualification, and Reliability
- Materials Research Group, Inc., Wheat Ridge, CO (United States)
- Polestar Technologies, Inc., Needham Heights, MA (United States)
The effects of ethylene-vinyl acetate (EVA) discoloration due to accelerated field or laboratory exposure on the encapsulated silicon (Si) solar cells or EVA/glass laminates were characterized quantitatively by using non-invasive, non-destructive ultraviolet-visible (UV-vis) spectrophotometry, spectrocolorimetry, spectrofluorometry, scanning laser OBIC (optical beam induced current) spectroscopy, and current-voltage (I-V) and quantum efficiency (QE) measurements. The results show that the yellowness index (YI) measured directly over the AR-coated solar cells under the glass superstrate increased from the range of {minus}80 to {minus}90 to the range of {minus}20 to 15 as the EVA changed from clear to brown. The ratio of two fluorescence emission peak areas generally increased from 1.45 to 5.69 as browning increased, but dropped to 4.21 on a darker EVA. For a solar cell with brown EVA in the central region, small-area grating QE measurements and scanning laser OBIC analysis between the brown and clear EVA regions showed that the quantum efficiency loss at 633 nm was 42%--48% of the loss at 488 nm, due to a reduced decrease of transmittance in browned EVA at the longer wavelengths. The portion of the solar cell under the browned EVA showed a decrease of {approximately}36% in efficiency, as compared to the cell efficiency under clear EVA. Transmittance loss at 633 nm was 38% of the loss at 488 nm for a light yellow-brown EVA/glass laminate that showed a small increase of 10 in the yellowness index.
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 276865
- Report Number(s):
- CONF-960513-; TRN: IM9636%%540
- Resource Relation:
- Conference: 25. photovoltaic solar energy conference, Washington, DC (United States), 13-17 May 1996; Other Information: PBD: 1996; Related Information: Is Part Of NREL preprints for the photovoltaic specialists conference of IEEE twenty-five; Gwinner, D. [ed.]; PB: 172 p.
- Country of Publication:
- United States
- Language:
- English
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