Rational design of tetraphenylethylene-based luminescent down-shifting molecules: photophysical studies and photovoltaic applications in a CdTe solar cell from small to large units

Abstract

A rational design strategy of novel fluorophores for luminescent down-shifting (LDS) application was proposed and tested in this paper. Three new fluorophores (1a–c) with specific intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) characteristics were synthesized as LDS molecules for increasing the output short circuit current density (J_sc) of a CdTe solar cell. Photophysical studies of their solution and solid states, and photovoltaic measurements of their PMMA solid films applied on a CdTe solar cell suggested that the specific spectroscopic properties and J_sc enhancement effects of these molecules were highly related to their chemical structures. The J_sc enhancement effects of these fluorophores were measured on both a CdTe small cell and a large panel. An increase in the output J_sc by as high as 5.69% for a small cell and 8.88% for a large panel was observed. Compared to a traditional LDS molecule, Y083, these fluorophores exhibited more superior capabilities of LDS.