Fluorescence properties of dye doped mesoporous silica

Abstract

Abstract. In this paper we present a review of the main results we obtained studying the emission properties of organicinorganic hybrids obtained combining mesoporous silica and Xantene dyes, in particular the standard referenc Rhodamine 6G. The purpose of the review is to show the possibility to efficiently "dope" the transparent inorganic porous matrix to obtain promising systems for photonic and biomedical applications. The strategies to solve the concentration effect and the leaching phenomenon are discussed within the framework of the single exciton theory.

Synthesis and optical properties of covalently bound Nile Red in mesoporous silica hybrids – comparison of dye distribution of materials prepared by facile grafting and by co-condensation routes

“…43 For the synthesis of the co-condensed NR-functionalized silica hybrids a solution of tetraethyl orthosilicate (TEOS), variable amounts of precursor 5, hexadecyl-trimethyl-ammonium bromide (C 16 TMABr), ethylamine, methanol, and deionized water was prepared with molar ratios of 1.00 : x : 0.140 : 2.40 : 2.00 : 100 (molar ratios x of precursor 5 are given in Table 6). First the template C 16 TMABr was dissolved in deionized water and ethylamine, which was employed as a 70 wt% aqueous solution before TEOS and the molar amount x of precursor 5 in methanol were added. For the syntheses of materials 7f-h 10 molar equivalents of methanol were used.…”

Silica-Coated Metal Chelating-Melanin Nanoparticles as a Dual-Modal Contrast Enhancement Imaging and Therapeutic Agent

“…The shift of emission is common phenomenon when dye molecules are labeled on or incorporated with NPs. 45,46 The enhanced fluorescent intensities of Gd-Mel@SiO 2 -1, 2, 3 were measured as gradually increased 7, 15, and 30 times higher fluorescent than that of bare Gd-Mel NP (Figure 4d). The same fluorescent enhancement with silica nanocoating was further confirmed with fluorescein isothiocyanate (FITC; ex/em = 483/530) having different excitation/emission range with TRITC (ex/em = 532/569) (Figure S7).…”

“…The shift of emission is common phenomenon when dye molecules are labeled on or incorporated with NPs. 45,46 The enhanced fluorescent intensities of Gd-Mel@SiO 2 -1, 2, 3 were measured as gradually increased 7, 15, and 30 times higher fluorescent than that of bare Gd-Mel NP (Figure 4d). The same fluorescent enhance- , and 3 that corresponding to Gd-Mel@SiO 2 -1, Gd-Mel@SiO 2 -2, and Gd-Mel@SiO 2 -3, respectively.…”

Photoluminescent Silica Nanostructures and Nanohybrids

“…Highly pure synthetic SiO 2 exhibits red emission at ~650 nm (λ ex = 260 nm and 590 nm) (Figure 2B), [3,73] with lifetime of ~45 μs. [56,73] It is quenched upon exposure to air and is often assigned to NBOHCs. [74] However, this is not the only opinion in this matter.…”

“…The slow, air-resistant band (τ � 7.5 μs) recovered at λ ex = 240 nm (or 388 nm) and λ em = 514 nm is due to dioxasilyrane, �Si(O 2 ). [56,60,61] The green band with microsecond lifetime is attributed to �SiÀ H. [73,76] Two �SiÀ H species are expected to be produced because of the confinement of one water molecule between two nanoparticles. [12] Silanol groups present on the surface of silica play a significant role in the retention of water molecules.…”