Heteroleptic Cu(I) complex with vapochromism and its application as electrochromic material

Abstract

Cu(I) complexes have garnered substantial attention in recent years because of their intriguing photophysical properties and their applications in different fields. Herein, we have reported a new four‐coordinated heteroleptic Cu(I) complex using dicnq, a 1,10‐phenanthroline‐based cyno‐substituted ligand, and Xantphos, a bulky as well as rigid chelating diphosphine ligand. The synthesized complex is characterized by multinuclear NMR and HRMS and described as [Cu (Xantphos)(dicnq)]PF6 (1). Complex 1 exhibits absorption within the range of 380–500 nm and emits around 700 nm, attributed to the metal‐to‐ligand charge transfer transition. Theoretical calculations suggest that the HOMO is predominantly located on the Cu(I) center, whereas LUMO is associated with the dicnq ligand. Further, 1 was found to show vapochromic behavior and blue‐shifted emission was observed in the presence of solvent vapors which can show π–π interaction with dicnq. Notably, the complex demonstrates electrochromic activity, prompting the fabrication of a device (ITO/P3HT/Cu complex/ITO) for an in‐depth exploration of its electrochromic properties. The working potential range for the device was found to be ±3 V. On and Off states show the device has an impressive contrast ratio of ~40% and 38% at 520 and 800 nm, respectively. In addition to this, the device shows rapid coloration and bleaching times of 0.8 and 0.5 s, respectively. In terms of contrast, switching speed, stability, and efficiency values at two different wavelengths, the device shows good electrochromic results.