Effects of Multiple Organic Dyes for Luminescent Down-Shifting Layers Application

Abstract

High energy photons in the UV region are not efficiently used in solar cells and limit the overall efficiency of the cell. Luminescent Down-Shifting (LDS) layers can be used to convert the high energy photons to a lower energy before it reaches the cell, which is more efficiently absorbed. In this study, an investigation of the optics of polymer thin-films LDS layer when comprising of mixed organic dyes, against single dye thin-films was investigated. The effect of creating a layer comprising of an equal ratio of BASF Lumogen Yellow 083, Lumogen Orange 240, and Lumogen Violet 570 in a polymethyl methacrylate (PMMA) polymer was investigated and compared to the experimental results from each single dye. This aided in determining whether using multiple organic dyes in a single film was beneficial for use as an LDS material. The interaction of the dyes with each other was investigated. It was determined that the combination of dyes created a larger absorbance range following the trend of each of the dyes it contained. The resulting emission of the mixed layer has an emission peak at the wavelength matching the longest emission peak wavelength of the comprising dyes. Further tests containing only two of the Lumogen dyes agreed with this finding.