Nanostructured organosilicon luminophores in highly efficient luminescent down-shifting layers for thin film photovoltaics

• Printed luminescent down-shifting layers with novel nanostructured luminescent molecules.
• Both PVB- and EVA-based dried layers with NOLs retain luminescence efficiencies of 82–90%.
• Novel LDS layers increased efficiency of CIGS solar cell by up to 4.3%.
• Optimum absorption spectrum and structure of luminescent molecules were determined.

We use a new type of solution processed luminescent molecules – nanostructured organosilicon luminophores (NOLs) – in printed luminescent down-shifting layers for photovoltaic light harvesting. We show that NOLs exhibit a high luminescent efficiency of 82–90% when added into two chemically different polymer matrices that are commonly used for photovoltaic encapsulation: polyvinyl butyral and ethylene-vinyl acetate. The coated layers are optimized to maximize both UV absorbance and visible light emission and transmittance. Attaching the luminescent layers onto a CIGS solar cell significantly improves the external quantum efficiency in the UV region: from 1% to 55% at 360 nm. As a result, the short circuit current density and power conversion efficiency increase by up to 3.2–4.3%. After experimental verification of our optical simulation model, we employ it to determine the ideal molecular structure of NOLs for luminescent down-shifting applied to CIGS.

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