Synthesis, structure, and spectroscopic properties of Cu⁺ complexes and its application to solar cells

Abstract

A series of Cu⁺ complexes, [Cu₂(L)(dppe)₂](BF₄)₂ (1), [Cu₂(L)(dppp)₂](BF₄)₂·2CH₃CN (2), and [Cu₂(L)(dppe)₂](ClO₄)₂ (3) (L = N,N′-bis(dipyridin-2-ylmethylene)benzene-1,4-diamine, dppe = 1,2-bis(diphenylphosphino)ethane, and dppp = 1,3-bis(diphenyl phosphino)propane), have been synthesized and characterized by IR, ¹H NMR, ³¹P NMR, UV–vis spectrum, and X-ray crystal structure analysis. The structural analysis reveals each Cu⁺ is four-coordinate N₂P₂ and adopts a distorted-tetrahedral geometry. Crystal structures of 1–3 contain 1-D supramolecular arrays constructed by intermolecular π⋯π interactions, with variations in π-stacking patterns. The ordered-layer-lattice or CH₃CN is located between 1-D arrays. The absorption peaks of 1 and 2 in acetonitrile at room temperature display ILCT and MLCT absorptions. Emission experiments show solid-state emissions of 1 and 2 are not similar to those of solution samples. The conversion efficiency of 1 and 2 in dye-sensitized solar cells is extremely poor (<0.1%).

Keywords:

• Copper(I) complexes
• Crystal structures
• Spectra
• DSSC

Additional information

Funding

This work was financially sponsored by the Talent Introduction Funds of Sichuan University of Science and Engineering [grant number 2014RC29]; Key Project of Sichuan Education Department [grant number 15ZA0223].