Polarized and blue-shifted fluorescent MEH-PPV@MOF synthesized via direct chain-introduction

Polarized fluorescent polymers can be promisingly used for many applications. In this work, the polarized fluorescent poly[2-methoxy,5-(2′-ethylhexyloxy)-1,4-phenylene vinylene]@MOF (MEH-PPV@MOF) composites were synthesized via the direct chain-introduction method. Firstly, long-range ordered porous metal-organic framework (MOF) crystals were synthesized. Through morphology observation and X-ray diffraction measurement, the water stability, thermal stability and structural stability of synthesized MOF were analyzed, to determine the preservation treatment of the material and the process parameters of introducing polymer chains in the subsequent experiment. Then, the MEH-PPV chains were directly introduced into the MOF channels via a solution-mediated incorporation approach. The measurement results of powder X-ray diffraction, nitrogen adsorption and Fourier transform infrared spectroscopy showed that the MEH-PPV chains were successfully introduced into the MOF channels. Finally, the fluorescent properties of the MEH-PPV@MOF composites were characterized via the photoluminescence spectroscopy. It was found that the accommodation of MEH-PPV chains within 1-D channels of MOF led to a strong blue-shift of the photoluminescence spectrum, due to the quantum confinement effect. Also, the polarization ratio calculated from the polarization luminescence spectra of the composites was 2.215. This indicates that the MEH-PPV@MOF composites prepared by the direct chain-introduction method with the help of the solution-mediated approach have good photoluminescence anisotropy.