Dye-doped parylene-based thin film materials: Application to luminescent solar concentrators

Novel thin films of dye-doped parylene were produced by a deposition technique consisting in a coarse vacuum co-sublimation of parylene C dimer and the perylenediimide dye Lumogen® F Red 305 (LR). In order to obtain parylene films containing different dye concentrations, LR was sublimated at temperatures ranging from 290 °C to 330 °C. The deposited films were characterized by FT-IR analysis, atomic force microscopy (AFM), optical absorption and emission spectroscopy. FT-IR analysis shows that LR is embedded in the parylene matrix, whose properties are not significantly affected by the dye incorporation. AFM analyses highlight the very low roughness of the deposited films, which is particularly important for optical applications, where light scattering at the air/film interface must be minimized. The optical properties of LR are preserved in the deposited films and the films exhibit the typical red light emission around 600 nm. No concentration quenching effects are found even at the highest LR concentrations obtained in this work, thus confirming the capability of the co-sublimation technique to obtain finely dispersed dye-containing films. Thin film luminescent solar concentrators (LSCs) were also produced by depositing LR-containing parylene films on glass and polymer waveguides and their properties were tested by measuring the output power of different solar cells coupled to one edge of the waveguide. Optical efficiency and power conversion efficiency of the LSC-based systems were then measured.

► Lumogen® Red-containing parylene films have been produced. ► A very fine dispersion of the dye molecules in the polymer matrix has been attained. ► LSCs have been produced and tested by depositing the films on plastic and glass slabs.