Synthesis and Physico-Chemical Properties of Homoleptic Copper(I) Complexes with Asymmetric Ligands as a DSSC Dye

Abstract

To develop low-cost and efficient dye-sensitized solar cells (DSSCs), we designed and prepared three homoleptic Cu(I) complexes with asymmetric ligands, M1, M2, and Y3, which have the advantages of heteroleptic-type complexes and compensate for their synthetic challenges. The three copper(I) complexes were characterized by elemental analysis, UV-vis absorption spectroscopy, and electrochemical measurements. Their absorption spectra and orbital energies were evaluated and are discussed in the context of TD-DFT calculations. The complexes have high VOC values (0.48, 0.60, and 0.66 V for M1, M2, and Y3, respectively) which are similar to previously reported copper(I) dyes with symmetric ligands, although their energy conversion efficiencies are relatively low (0.17, 0.64, and 2.66%, respectively).

Photoactive Copper Complexes: Properties and Applications

“…In 2021, the Inomata and Masuda groups reported the development of three new homoleptic copper­(I) complexes bearing nonsymmetrical ligands and their application in copper-based DSSCs (entries 26–28 in Table ). The ligands used ( NN 406 , NN 407 , and NN 504 ) possess a single anchoring substituent, and one of them ( NN 504 ) also features one electron-donating substituent on the chelating cycle free from anchoring group, in an attempt to combine the asymmetrical electronic contribution of the ligands around the copper­(I) center with the ease of synthesis and higher stability of homoleptic complexes. The best performing cell reached up to 2.66% overall efficiency and compared well with the 1.9% achieved for the related symmetric dye using dmdcbpy ( NN 279 ).…”

Back to the future: asymmetrical DπA 2,2′-bipyridine ligands for homoleptic copper(i)-based dyes in dye-sensitised solar cells

“…This strategy has been little investigated and has not delivered convincing results to date. 59–61 We also note that the DπA ligands themselves possess the characteristics of a purely organic photosensitiser and it is instructive to compare the performance of the ligand as an organic dye sensitiser with that of the homoleptic [Cu(DπA) 2 ] + complexes.…”

A Fascinating Trip into Iron and Copper Dyes for DSSCs

“…In 2021, Inomata and Masuda et al [45] published the three homoleptic asymmetric dyes 26a-c (structures in Figure 11). Compounds 26a and 26c had two bipyridine ligands while 26b had two 2-pyrazol-1-yl pyridines.…”