Method for measurement of the directional/hemispherical reflectance of photovoltaic devices

A novel method, and the relative apparatus, are described which permit to m easure the directional/hemispherical reflectance of a surface at incidence angles theta in the interval 0-90 degrees. The method, suitable for the cha racterization of optically homogeneous as well as heterogeneous samples, is named "differencing reflection method" as the reflectance of the sample, R -dh(theta, lambda), is derived from differences among the reflectance signa l measured for the sample and those measured for two diffuse reflectance st andards. In order to be applied, the method requires the knowledge of the d irectional/hemispherical reflectance of the standards for the wavelength ra nge of interest and for incidence angle interval 0-90 degrees. The method h as been applied to measurements of R-dh(theta, lambda) of solar cells. (C) 2000 Elsevier Science B.V. All rights reserved.