The effect of donor-modification in organic light-harvesting motifs: triphenylamine donors appended with polymerisable thienyl subunits

Abstract

A family of seven organic triphenylamine-based dyes suitable for dye-sensitized solar cell (DSSC) applications is reported. The donor portion of these dyes has been systematically modified using polymerisable thienyl subunits. The physicochemical properties and device performance are discussed with device efficiencies ranging from 5.51 to 6.65%.

Exploring Structure-Property Relationships in a Bio-Inspired Family of Bipodal and Electronically-Coupled Bistriphenylamine Dyes for Dye-Sensitized Solar Cell Applications

“…Not to be forgotten, the 3-thienyl-substituted TPA (4) did not have electrochemical or optical properties as desirable (high ε in the visible portion of the spectrum) as 1a (-H) yet it still was one of the top performers. This can be rationalized consistent with our previous work [51] as high energy absorption behaviour (between 350-400 nm) is significant in organic dye performance (evidenced by J SC ), and like -SR derivatives they are also shown to have favourable electrolyte interactions [53].…”

“…In addition, the complete compendium of UV-Vis absorption (Supplementary Figure S1) and fluorescence spectra (Supplementary Figure S2) are included in the supporting information. All the dyes (with the exception of 4) exhibit weak or negligible fluorescence behavior in solution, consistent with previous observations [31,51]. In addition, time-dependent density functional theory (TD-DFT) calculations were performed to better appreciate the dominant optical transitions.…”

“…Having two attachments to the titania surface will restrict the degrees of freedom of the dye and likely prevent aggregation and close proximity between dyes on the surface. Finally, while it may appear as an outlier, molecule 4 uses a 3-thienyl substituent to increase the optical cross section of the distal donor, while only modestly altering the redox properties and builds on our previous work of creating polymerizable DSSC dyes [51].…”

“…In addition, each group contains dyes with no substituents -H (a), or -OMe (b), -OHex (c), and -SMe (d) substituents on the distal TPA unit. Dye 4, represents a different distal TPA modification (3-thienyl) and is an extension of the Group 1 family and previous work [51]. L1 is a previously reported dye [52] that we use as a benchmark.…”

Push‐Pull N‐Annulated Perylene‐Based Sensitizers for Dye‐Sensitized Solar Cells: Theoretical Property Tuning by DFT/TDDFT

“…The D–π–A configuration is effective for light harvesting and intermolecular charge transfer (ICT) between the electron donor and the electron acceptor. Triphenylamine and diphenylamine are electron rich Lewis bases and are useful electron donor substituents . A recently reported triphenylamine linked N ‐annulated perylene electron donor ( D1 ) exhibited good PCE in a DSSC , .…”