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

Abstract

A novel method, and the relative apparatus, are described which permit to measure the directional/hemispherical reflectance of a surface at incidence angles θ in the interval 0–90°. The method, suitable for the characterization of optically homogeneous as well as heterogeneous samples, is named “differencing reflection method” as the reflectance of the sample, R dh( θ, λ), is derived from differences among the reflectance signal measured for the sample and those measured for two diffuse reflectance standards. In order to be applied, the method requires the knowledge of the directional/hemispherical reflectance of the standards for the wavelength range of interest and for incidence angle interval 0–90°. The method has been applied to measurements of R dh( θ, λ) of solar cells.