Improvement of spectral response by co-sensitizers for high efficiency dye-sensitized solar cells

Abstract

Simple donor–π–acceptor organic dyes, denoted as HC3, HC4, and HC5, were synthesized as co-sensitizers for black dye based dye-sensitized solar cells. By tuning the electron-donating moieties and side alkyl chain lengths of the co-sensitizers, the spectral photoresponse was greatly enhanced from the UV to the entire visible region. The short circuit current density was significantly improved by 8.5% in the BD + HC5 cell with respect to the cell with BD only, and consequently a high efficiency of 11.6% was achieved.