Comparative study on N,N-di-p-tolylaniline-based D-π-A1-π-A2 sensitizers by tuning the auxiliary acceptor for dye-sensitized solar cells

Abstract

We report the synthesis and DSSCs performance of two dye sensitizers XD1 and XD2 with D-π-A1-π-A2 structure bearing difluorobenzo[c][1,2,5]thiadiazole (DFBT) and diketopyrrolopyrrole (DPP)-based as auxiliary acceptor moieties. The effect of DFBT or DPP on the photophysical, electrochemical, and photovoltaic properties of the target dyes were investigated. It is found that DPP-containing XD2 achieve higher Jsc result from its wider absorption spectrum ranging from visible to near-infrared region, higher molar absorption coefficient in the low-energy region and stronger photocurrent generation as compared to the DFBT-containing XD1. Additionally, the longer electron lifetime and increased charge recombination resistance of XD1 make it achieves higher Voc. The photovoltaic properties of the DSSCs are synthetically influenced by Jsc and Voc. Eventually, the investigation of photovoltaic performance of DSSCs indicates that XD1 obtains slightly higher power conversion efficiency (PCE) of 5.04%, but the PCE of the DSSCs based on the dye XD2 with 1 mM CDCA as co-adsorbent is increased to 6.14%.