Lab testing of 100mm × 100mm solar window prototypes (2012−2014) containing various interlayer compositions with different concentrations and chemistries of luminophore particles dispersed into UV-curable epoxy layers of ∼1mm thickness. The glass sample images are organized into three horizontal rows, each row containing the same solar window sample, but showing the measurements of either the open-circuit voltage (left), or the short-circuit current (right). Typical appearance of transparent fluorescent epoxy in its liquid state is also illustrated in the bottom row, together with the measurement results obtained from the three above-shown window samples irradiated by an identical solar simulator beam. Substantial variations in the measured electrical parameters correlated with the differences in the interlayer composition (more details available from Ref. [18]).