Investigation of a copper(i) biquinoline complex for application in dye-sensitized solar cells

Abstract

The synthesis, properties and application of a Cu(2,2 0 -biquinoline-4,4 0 -dicarboxylic acid) 2 complex in dyesensitized solar cells (DSSC) are described. The complex is electrochemically stable and strongly absorbing with a molar extinction coefficient at l (max) ¼ 564 nm of 11 700 M À1 cm À1 (in MeOH).Experimental and computational data indicate that the HOMO, LUMO and electronic excited state energy levels are appropriate for functionality in a DSSC. From cyclic voltammetry the HOMO is estimated to be À5.27 eV, as supported by computational work, which locates the HOMO at À5.78 eV.From electrochemical, absorption and emission experiments, the MLCT energy levels are expected to be appropriate for electron injection into the TiO 2 conduction band. Our computations support this and locate the key MLCT transition at 563 nm. Despite this, the efficiency in DSSCs is extremely low (<0.1%) suggesting that the dye does not inject excited electrons into the TiO 2 conduction band.

To deprotect or not to deprotect: Phosphonate ester versus phosphonic acid anchor ligands in copper(I)-based dye-sensitized solar cells

“…We and others are focusing both our experimental and theoretical attention on dyes in which the chromophore is a copper(I) complex [4,5,6,7,8,9,10] Copper(I) diimine complexes are labile and the rapid ligand exchange processes [ 11 ] predicate against the isolation of chemically pure heteroleptic complexes, making this a challenging goal [12]. The recognition of this lability allowed us to develop a method of assembling TiO 2 -bound heteroleptic [Cu(L anchor )(L ancillary )] + dyes directly on a surface [4].…”

Modulation of Fluorescence Emissions of Copper(II) 2,2′-biquinoline-4,4′-dicarboxylates

“…The choice of this compound is due to following reasons: (a) The anion of this compound H 2 bqca is big in size, hence a non‐covalent assembly constructed by such anions may be easily dismantled; (b) A big anion will be reluctant to coordinate to a metal ion; (c) H 2 bqca being a flexible molecule will have possibility to adopt different orientations by rotation around C ipso ‐C ipso bond as illustrated in Figure ; (d) There is existing literature on coordination ability of the H 2 bqca for chelation and to form coordination polymers; and (e) Most importantly H 2 bqca is likely to π‐stack as a characteristic feature associated with quinoline based compounds. [8] It is also well known fact that H 2 bqca is commonly used to detect Cu + ions and sugar; such detections are based on redox and fluorescence properties . Besides these, H 2 bqca chelates to Cu 2+ ions .…”

“…Besides these, H 2 bqca chelates to Cu 2+ ions . It also forms framework structures with interesting properties– having applications in material science and supramolecular chemistry. [15] H 2 bqca has active hydrogen atoms, hence may show excited state proton transfer observed in structurally related systems .…”

Synthesis, Structural Characterisation, and Spectroscopic Properties of Copper(I) Complexes and their Applications to Dye-Sensitised Solar Cells

“…[7][8][9][10][11][12] DSSCs employing Ru II -based complexes as sensitisers have shown attractive conversion efficiencies, [13][14][15][16][17] but metallic ruthenium is highly expensive and is in short supply. [18] Copper (I) complexes have gained importance as alternatives to Ru II -based complexes in photophysical and photoelectrochemical applications, [19][20][21] especially because of their ease of synthesis and the high abundance of copper in comparison with metallic ruthenium. [22] The excited state and photophysical properties of Cu I complexes involving diphosphine and polypyridyl ligands have been reported.…”