Optical Properties of EVA Films Including V570 for Transparent Luminescent Solar Concentrator

We fabricated a transparent luminescent solar concentrator (LSC) film using Lumogen F Violet 570 (V570) luminescent molecules and polyethylene-co-vinylaccetate (EVA) polymer. The transparent LSC was produced by a solution process (Doctor Blade coating) using a tetrahydrofuran solvent. We measured physical properties such as thickness, absorption efficiency, emission efficiency, and photocurrent characteristics of the LSC films. We also discuss the physical properties of the LSC films by observing the crystallinity and surface morphology using X-ray diffraction and atomic force microscopy. During the formation of LSC films, V570 molecules did not induce macroscopic changes, but had a significant effect on nanoscale morphology, i.e., surface roughness. In addition, changes in the light scattering characteristics were observed when the V570 concentration increased, which was found by X-ray diffraction to be related to the formation of V570 crystals, not EVA crystals. The light scattering and surface roughness of a film could be improved through heat treatment. As a result, we obtained similar to 1.3 times larger photocurrent in thermally treated LSC films.