Multichromophoric sensitizers based on calix[4]arene scaffold and 4 H -pyranylidene moiety for DSSCs application

Abstract

We have synthesized lower rim 1,3-derivatives of 4-tert-butylcalix[4]arene-appended dyes in order to test their physical and photovoltaic properties. These dyes consist in a donor group based on triphenylamine and/or 4H-pyranylidene moieties, a heteroaromatic π-conjugated spacer such a thiophene ring and an acceptor group like cyanoacetic acid. The molar extinction coefficient of these systems increases with the introduction of the second dye in the same molecule and it is observed an extended band along the visible spectrum. The use of calix[4]arene platform with other dyes could lead to a new strategy to the achievement of novel panchromatic dyes.

Modification of the electronic properties of the π-spacer of chromophores linked to calix[4]arene platform for DSSCs applications

“…In order to obtain further information on the electronic structure of the new dyes we have performed DFT calculations using acetyl derivatives Ac-8 and Ac-9 (Chart 2) as simplified models of calixarene derivatives 8 and 9. The results of the calculations have been also compared to the acetyl derivative Ac-TPA [16] used as a simpler analogous of compound Cx-2-TPA.…”

“…This behavior was also observed in analogous triphenylamine derived dyes. [16] The Cartesian coordinates of all the calculated molecular geometries are included as supplementary material.…”

“…The role of calix [4]arene as donor unit was reported by Tan et al [21] and two papers have been published by our research group using the p-tert-butyl-calix [4]arene as scaffold to orient the anchoring groups. [15,16] In our previous work [15], it was shown that the molar extinction coefficient of the two branched dye with TPA increased when it is compared with the monosubstituted calix [4]arene. However, the IPCE spectrum showed that the injection of photons above 600 nm is negligible.…”

“…[12,13] Our research group has used the p-tert-butyl-calix [4]arene scaffold to integrate several chromophores in one single molecule, far away enough to behave as independent chromophores and so providing several light-harvesting units per molecule which favors high molar extinction coefficients. [14][15][16] Moreover, the p-tert-butyl substituted calix [4]arene derivative has bulky alkyl chains. This functionalization increases the solubility of the systems and hinders dye aggregation.…”

Difunctionalized dyes for DSSCs based on two different scaffolds: p-tert-butylcalix[4]arene or isophthalic acid

“…In this field, our research group prepared double systems based on calix [4]arene scaffold with an alkyl linkage in the πbridge. [19,20] As far as we know there are no dyes based on calix [4]arene derivatives with an alkyl linkage in the donor part. Then in this work we will study the photophysical and photovoltaic properties of dyes based on calix [4]arene derivatives linked by the aniline moiety which acts as donor part (D), a thiophene as π-spacer (π) and cyanoacetic as acceptor (A).…”