In‐situ Synthesis and Photoluminescence of a Europium Porphyrin Complex Incorporated in the Silica Matrix

A practicable synthesis method is explored to synthesize a europium porphyrin complex in which a water‐soluble positively charged 5,10,15,20‐tetrakis(4‐trimethylammoniophenyl)porphyrin iodide, H₂TMePPI, is immobilized into the sol‐gel silica matrix and then in‐situ metallized with the Eu³⁺ ion. The product is characterized by means of the solid UV diffusion reflection spectra, fluorescence spectra, and thermal gravimetric analysis (TG). The solid UV diffusion reflection spectra show that the number of Q bands in the product is less than that of the H₂TMePPI ligand, which is one of the important characteristics of porphyrin metallization. The fluorescence spectra of the product are different from that of the silica doped with free Eu³⁺ ions, implying the different function of Eu³⁺ ions in the product. The TG curves show that the thermal stability of the Eu(III)TMePPI entrapped into silica is higher than that of the H₂TMePPI. The effect of a heat treatment and an UV‐light irradiation on the photoluminescence properties of the composite is investigated in details. The stronger interaction between Eu(III)TMePPI and SiO₂ in the composite is responsible for the different spectra.

Keywords:

• Europium porphyrin complex
• silica matrix
• in‐situ synthesis
• sol‐gel process
• photoluminescence

We acknowledge the support of the Excellent Youth Teacher Program and Research Foundation of Returned Student Abroad, MOE of China.