Di-amidosils with tunable structure, morphology and emission quantum yield: the role of hydrogen bonding. Issue 26 (9th June 2015)

• Record Type: Journal Article
• Authors: Nunes, S. C.; Hümmer, J.; Freitas, V. T.; Ferreira, R. A. S.; Carlos, L. D.; Almeida, P.; de Zea Bermudez, V.
• Is Part Of: Journal of materials chemistry. Volume 3:Issue 26(2015)
• Page Start: 6844
• Page End: 6861
• Publication Date: 2015-06-09
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c5tc00721f
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Di-amidosil hybrids with variable structure, morphology and photoluminescence properties were obtained using different experimental conditions. A correlation between the emission quantum yield value and the degree of order of the amide–amide hydrogen-bonded array was established for mono- and di-amidosils. Abstract : Tailoring of the structure (from amorphous to highly ordered lamellar), morphology (from a homogenous texture to fibers, microparticles, seaweeds- and desert rose-like shapes) and photoluminescence features of five di-amide crossed-linked decyl/siloxanes (di-amidosils, d-A(10)) was achieved via sol–gel chemistry and self-assembly from a single precursor through a fine control of the reaction conditions (water content, catalyst presence/type (HCl or NaOH)/concentration and co-solvent presence/type (ethanol or DMSO)). All the hybrids analyzed are multi-wavelength emitters under UV/visible excitation. Irrespective of the degree of order of the materials, the highest emission quantum yield values ( ca. 013 ± 0.01 excited at 400 nm) were found in samples synthesized in the presence of a catalyst. Comparison of the present data with those reported by our group for a shorter chain di-amidosil and for mono-amidosils revealed that in the amidosils the emission quantum yield is intimately associated with the degree of order of the amide–amide hydrogen-bonded network. This enabled us to establish for the first time a rational and straightforward way of predicting grosso modo the magnitude of the emission quantum yield of an amidosil hybrid prior to measurements, which requires simply the analysis of the amide I band of the FT-IR spectrum. This correlation opens the way to exciting new prospects for the design of new luminescent organic–inorganic hybrids with enhanced properties.