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

Abstract

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 360nm. 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.