Microfibers doped with a Cu(I) complex for photophysical performance improvement: Synthesis and characterization

•A diamine ligand of steric hindrance, conjugation chain and electron-pulling was designed.•It was anticipated to favor emissive performance of its Cu(I) complex.•Electronic transition of this Cu(I) complex suffered from structural distortion.•This complex was doped into polymer fibers to limit such structural distortion.•Emission blue shift, long excited state lifetime and improved photostability were obtained.

This paper reported a diamine ligand based on a typical electron-pulling group of oxadiazole ring. Its steric hindrance, long conjugation chain and electron-pulling group were anticipated to favor emissive performance of corresponding Cu(I) complex. This Cu(I) complex was prepared and characterized in detail by means of NMR, single crystal analysis, density functional theory calculation and photophysical measurement. It was found that this Cu(I) complex took a distorted tetrahedral coordination field, its electronic transition showed a mixed character of metal-to-ligand-charge-transfer (MLCT) and ligand-to-ligand-charge-transfer (LLCT) which suffered from intense structural distortion. To effectively limit MLCT excited state geometric distortion, this Cu(I) complex was immobilized into poly(vinylpyrrolidone) (PVP) fibers through electrospinning method. Photophysical performance comparison between solid state sample, solution sample and electrospinning fiber samples was performed. It was found that MLCT geometric distortion could be effectively limited by polymer immobilization effect, showing improved emissive performance such as emission blue shift, long excited state lifetime and improved photostability.

Graphical abstractThis paper reported a diamine ligand of steric hindrance, long conjugation chain and electron-pulling group which were anticipated to favor emissive performance of corresponding Cu(I) complex. To effectively limit MLCT excited state geometric distortion, this Cu(I) complex was immobilized into poly(vinylpyrrolidone) (PVP) fibers through electrospinning method, showing improved emissive performance such as emission blue shift, long excited state lifetime and improved photostability.Figure optionsDownload full-size imageDownload as PowerPoint slide