Efficiency enhancements in solid-state hybrid solar cells via reduced charge recombination and increased light capture

Abstract

We compare a series of molecular sensitizers in dye-sensitized solar cells containing the organic hole transporter 2,2′,7,7′-tetrakis(N,N-di-p- methoxypheny-amine)-9,9′-spirobifluorene (spiro-MeOTAD). Charge recombination is reduced by the presence of "ion-coordinating" moieties on the dye, with the longest electron lifetime and highest solar cell efficiency achieved using a novel sensitizer with diblock alkoxy-alkane pendent groups. By further increasing the optical path length in the active layer, we achieve a power conversion efficiency of over 5% under simulated sun light. © 2007 American Chemical Society.