Photophysical performance comparison between bulk Cu(I) complex and its electrospinning fibers: Synthesis and characterization

• A ligand having an electron-pulling group and its Cu(I) complex were reported.
• This complex was doped into a polymer host to suppress its geometric relaxation.
• Photophysical comparison between pure and composite samples was performed.
• Polymer immobilization effect improved emissive performance.

In this report, a diamine ligand having an electron-pulling group in its conjugation plane was designed. A methyl group was connected with this diamine ligand, hoping to further increase its steric hindrance. Its Cu(I) complex was synthesized and characterized by NMR, single crystal analysis and photophysical analysis. There was a distorted tetrahedral coordination field in this Cu(I) complex. Its onset electronic transition owned a mixed character of metal-to-ligand-charge-transfer which suffered from bad geometric relaxation. To limit this geometric relaxation and improve emissive performance, this Cu(I) complex was doped into a polymer host through electrospinning technique. Photophysical comparison between solid state sample, solution sample and composite samples indicated that excited state geometric relaxation was effectively limited by polymer immobilization effect, resulting in improved emissive performance, such as emission blue shift, long emission decay lifetime and better photostability.

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