Near-infrared absorbing isoindigo sensitizers: Synthesis and performance for dye-sensitized solar cells

A series of isoindigo-based metal-free organic sensitizers have been synthesized and used in dye-sensitized solar cells (DSSCs). Measurement data indicated that the fine-tuning of the donor or linker moiety could conveniently adjust the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels. All DSSCs sensitized by three new dyes displayed an efficient panchromatic spectra response with the improved light-harvesting capability in near-infrared region, in which a highest photovoltaic conversion efficiency of 5.56% was obtained by the DSSCs of benzene-bridge isoindigo-based sensitizer, with a short-circuit photocurrent density (J(sc)) of 13.16 mA/cm(2), an open-circuit photovoltage (V-oc) of 582 mV, and a fill factor (ff) of 0.73. (C) 2014 Elsevier Ltd. All rights reserved.