One of the most common measurements made by the solar energy industry today is quantification of a material’s surface reflectance. These materials are as diverse as metal coatings, semiconductor coatings, anti-reflective coatings on window material, as well as the window material itself. While both transmission and reflectance are of interest to the industry, we will consider only reflectance measurements in this technical note. These measurements are most commonly made between 300 nm and 1500 nm which is where the solar cell is responsive to energy from the sun. Reflection comes in two varieties, specular and diffuse. This technical note will concentrate on the instrumental accessories used to measure both types of reflection and compare/contrast spectra collected on the accessories.
Unfortunately many materials manifest a combination of both specular and diffuse reflectance.
This can present a problem in selection of the best reflectance accessory that will yield
Correct intensity data (%R) with minimal spectral artifacts. The primary goal of this technical
Note is to guide the user through the accessory selection process for different specular/
Diffuse samples. This will be achieved by measuring identical samples with varying contribution f diffuse and specular reflection, on three different reflection accessories, and then comparing the spectra generated.