Solar spectral optical properties of pigments--Part I: model forderiving scattering and absorption coefficients from transmittance andreflectance measurements
Pigment characterization is performed by dispersing thepigment into a transparent film of refractive index 1.5, andmeasuringspectral transmittance and reflectance. Measurements of the filmreflectance backed with black and white substrates are also used. A modelfor extracting the spectral backscattering coefficient S and absorptioncoefficient K from spectrometer measurements is presented. Interfacereflectances complicate the model. The film's diffuse reflectance andtransmittance measurements are used to determine S and K as functions ofa model parameter sigma that represents the ratio of forward to totalscattering. Sigma is used to estimate the rate at which incidentcollimated light becomes diffuse, and is determined by fitting themeasured film reflectance backed by black. A typical value is sigma=0.8.Then, the measured film reflectance backed by white is compared with acomputed value as a self-consistency check. Measurements on severalcommon pigments are used to illustrate the method.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE; California Energy Commission
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 929073
- Report Number(s):
- LBNL--54855; BnR: 600303000
- Journal Information:
- Solar Energy Materials and Solar Cells, Journal Name: Solar Energy Materials and Solar Cells Vol. 89; ISSN SEMCEQ; ISSN 0927-0248
- Country of Publication:
- United States
- Language:
- English
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