Enhanced NIR-fluorescent properties of Tm3+ complex combined with nano silica

Abstract

Tm3+ has obvious emission characteristics in near-infrared band. In the near-infrared region, Tm3+ are converted downward into fluorescent materials that are unstable under high temperature and acidic conditions. Moreover, the fluorescence performance of Tm3+ complex will be reduced in complex environment. In this work, Tm(TTA)3phen complex combined with nano-SiO2 was prepared by an improved sol-gel method, Tm3+ complex was successfully embedded into nano-SiO2 and on the surface of nano-SiO2, resulting in higher composite density of Tm3+ complex and nano-SiO2. Moreover, the SiO2-Tm(TTA)3phen hybrid materials behave quit stronger fluorescence properties compared with pure Tm(TTA)3phen complex and stronger structural stability compare with pure SiO2. The emission peak of SiO2-Tm(TTA)3phen underwent red shift, and fluorescent intensity at 802 nm was significantly enhanced almost 2 times compared with pure complex, and the intensity of 1231 nm and 1400–1500 nm were also enhanced, the emission lifetime of SiO2-Tm(TTA)3phen is 50.38 μs.