Synthesis and linear/nonlinear optical properties of a new class of ‘RHS’ NLO chromophore

Abstract

Examples of a new class of zwitterionic, ''right-hand side'' merocyanines containing a cyanodicyanomethylidenedihydrofuran electron acceptor have been prepared. As well as allowing for the facile synthesis of these chromophores, our synthetic methodology enables considerable variation in both the donor moiety as well as the extent of conjugation between the donor and acceptor systems. As expected, all of these ''right-hand side'' systems are negatively solvatochromic, with the difference between l max (polar vs. nonpolar solvents) increasing with the extent of conjugation. In accord with expectations, hyper-Raleigh scattering (HRS) measurements confirm that molecules with the greatest conjugation pathway (for e.g. 21c, 23c) have the largest first hyperpolarisabilites, b o . In addition, our HRS evaluation indicates that the 4-quinolinylidene donor nucleus is superior to both the 4-pyridinylidene and benzothiazolylidene systems. The figures of merit, m (calc) .b o(measured) , that we obtain for some of these compounds, are of a similar magnitude to the best ''left hand side'' examples reported in the literature. In order to demonstrate the versatility of our synthetic technique, representative polymer-tetherable derivatives of these compounds have been prepared, as have the corresponding TDI-based polyurethanes.

Synthesis, linear & non linear optical (NLO) properties of some indoline based chromophores

“…This is a well documented phenomenon and, therefore, entirely expected [15,16]. The inclusion of ring locking in the centre of the conjugated p-system, along with either t-butyl or diphenyl substitution on the central cyclohexene ring (compounds 11, 17, 18, 24, 25) has a minimal effect on the second-order nonlinear response.…”

Tin oxide as a photoanode for dye-sensitised solar cells: Current progress and future challenges

“…First, its isoelectric point (pH 4e5) [50,51], which is lower than that of anatase TiO 2 (pH~6e7) and ZnO (pH 9), results in inferior dye loading and eventually lower J SC . Second, the conduction band (CB) edge of SnO 2 , which is lower than that of TiO 2 and ZnO, results in (i) larger overpotential at the dye/MOS interface than that of TiO 2 and (ii) higher recombination of the photoexcited electrons with the reduced dye molecules and triiodide species, thereby simultaneously limiting the FF and V OC in the devices [51e59].…”

Nanowire-based hierarchical tin oxide/zinc stannate hollow microspheres: Enhanced solar energy utilization efficiency for dye-sensitized solar cells and photocatalytic degradation of dyes

“…Except for optimizing the material morphologies, an alternative route is to alter the photoanode/photocatalyst materials from a single semiconductor to composites [33,34]. For instance, by coupling different semiconductor oxides with SnO 2 , such as TiO 2 [35e38] and ZnO [39], the further improvements have been achieved in the photoconversion efficiencies of SnO 2 -based DSSCs and the photocatalytic degradation performance [40e43].…”