Increased short-circuit current density of production line CdTe mini-module through luminescent down-shifting

The application of luminescent down-shifting (LDS) has been shown to improve the short wavelength response of a variety of different photovoltaic devices. Cadmium sulphide/cadmium telluride (CdS/CdTe) heterojunction devices possess a great potential for improvement via LDS due to the parasitic absorption of blue light by the CdS buffer layer. This work is the first to investigate LDS applied to mini-modules (72 cm2 active area) cut from full-size CdTe modules from a production line. The addition of LDS layers containing Lumogen Yellow 083 and Violet 570 dyes was demonstrated to increase the short circuit current density (JSC) of the mini-module by up to 9% relative. It was shown that the addition of the Yellow 083 dye alone more than doubles the short wavelength (300–500 nm) response of CdTe mini-modules. External quantum efficiency measurements are presented that clearly identified the wavelength range of photocurrent enhancement, while increased efficiency was confirmed with current–voltage (I–V) measurements.

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► Thin PMMA layers were doped with Lumogen V570 and Y083 luminescent dyes.
► These layers were applied to CdTe spot cells (1.13 cm2) and mini-modules (72 cm2).
► Mini-module JSC increased by 9% with the layer doped with V570 and Y083 dyes.
► Mini-module JSC from 300 to 500 nm photons doubled for all layers containing Y083.