Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose
The photophysical behavior of eosin Y adsorbed onto microcrystalline cellulose was evaluated by reflectance spectroscopy, steady-state fluorescence spectroscopy and laser induced time-resolved luminescence. On increasing the concentration of the dye, small changes in absorption spectra, fluorescence...
Guardado en:
| Autores principales: | , , , , |
|---|---|
| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00318655_v88_n4_p831_Rodriguez |
| Aporte de: |
| id |
todo:paper_00318655_v88_n4_p831_Rodriguez |
|---|---|
| record_format |
dspace |
| spelling |
todo:paper_00318655_v88_n4_p831_Rodriguez2023-10-03T14:41:39Z Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose Rodríguez, H.B. Román, E.S. Duarte, P. MacHado, I.F. Vieira Ferreira, L.F. cellulose eosin fluorescent dye microcrystalline cellulose adsorption chemistry cold conference paper fluorescence hydrogen bond laser light luminescence molecular probe spectrofluorometry thermodynamics Adsorption Cellulose Cold Temperature Eosine Yellowish-(YS) Fluorescence Fluorescent Dyes Hydrogen Bonding Lasers Light Luminescence Luminescent Measurements Molecular Probes Spectrometry, Fluorescence Thermodynamics The photophysical behavior of eosin Y adsorbed onto microcrystalline cellulose was evaluated by reflectance spectroscopy, steady-state fluorescence spectroscopy and laser induced time-resolved luminescence. On increasing the concentration of the dye, small changes in absorption spectra, fluorescence redshifts and fluorescence quenching are observed. Changes in absorption spectra point to the occurrence of weak exciton interactions among close-lying dye molecules, whereas fluorescence is affected by reabsorption and excitation energy trapping. Phosphorescence decays are concentration independent as a result of the negligible exciton interaction of dye pairs in the triplet state. Lifetime distribution and bilinear regression analyses of time-resolved phosphorescence and delayed fluorescence spectra reveal the existence of two different environments: long-lived, more energetic triplet states arise from dyes tightly entrapped within the cellulose chains, while short-lived, less-energetic states result from dyes in more flexible environments. Stronger hydrogen bond interactions between the dye and cellulose hydroxyl groups lead in the latter case to a lower triplet energy and faster radiationless decay. These effects, observed also at low temperatures, are similar to those encountered in several amorphous systems, but rather than being originated in changes in the environment during the triplet lifetime, they are ascribed in this case to spatial heterogeneity. © 2012 Wiley Periodicals, Inc. Fil:Rodríguez, H.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00318655_v88_n4_p831_Rodriguez |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
cellulose eosin fluorescent dye microcrystalline cellulose adsorption chemistry cold conference paper fluorescence hydrogen bond laser light luminescence molecular probe spectrofluorometry thermodynamics Adsorption Cellulose Cold Temperature Eosine Yellowish-(YS) Fluorescence Fluorescent Dyes Hydrogen Bonding Lasers Light Luminescence Luminescent Measurements Molecular Probes Spectrometry, Fluorescence Thermodynamics |
| spellingShingle |
cellulose eosin fluorescent dye microcrystalline cellulose adsorption chemistry cold conference paper fluorescence hydrogen bond laser light luminescence molecular probe spectrofluorometry thermodynamics Adsorption Cellulose Cold Temperature Eosine Yellowish-(YS) Fluorescence Fluorescent Dyes Hydrogen Bonding Lasers Light Luminescence Luminescent Measurements Molecular Probes Spectrometry, Fluorescence Thermodynamics Rodríguez, H.B. Román, E.S. Duarte, P. MacHado, I.F. Vieira Ferreira, L.F. Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose |
| topic_facet |
cellulose eosin fluorescent dye microcrystalline cellulose adsorption chemistry cold conference paper fluorescence hydrogen bond laser light luminescence molecular probe spectrofluorometry thermodynamics Adsorption Cellulose Cold Temperature Eosine Yellowish-(YS) Fluorescence Fluorescent Dyes Hydrogen Bonding Lasers Light Luminescence Luminescent Measurements Molecular Probes Spectrometry, Fluorescence Thermodynamics |
| description |
The photophysical behavior of eosin Y adsorbed onto microcrystalline cellulose was evaluated by reflectance spectroscopy, steady-state fluorescence spectroscopy and laser induced time-resolved luminescence. On increasing the concentration of the dye, small changes in absorption spectra, fluorescence redshifts and fluorescence quenching are observed. Changes in absorption spectra point to the occurrence of weak exciton interactions among close-lying dye molecules, whereas fluorescence is affected by reabsorption and excitation energy trapping. Phosphorescence decays are concentration independent as a result of the negligible exciton interaction of dye pairs in the triplet state. Lifetime distribution and bilinear regression analyses of time-resolved phosphorescence and delayed fluorescence spectra reveal the existence of two different environments: long-lived, more energetic triplet states arise from dyes tightly entrapped within the cellulose chains, while short-lived, less-energetic states result from dyes in more flexible environments. Stronger hydrogen bond interactions between the dye and cellulose hydroxyl groups lead in the latter case to a lower triplet energy and faster radiationless decay. These effects, observed also at low temperatures, are similar to those encountered in several amorphous systems, but rather than being originated in changes in the environment during the triplet lifetime, they are ascribed in this case to spatial heterogeneity. © 2012 Wiley Periodicals, Inc. |
| format |
JOUR |
| author |
Rodríguez, H.B. Román, E.S. Duarte, P. MacHado, I.F. Vieira Ferreira, L.F. |
| author_facet |
Rodríguez, H.B. Román, E.S. Duarte, P. MacHado, I.F. Vieira Ferreira, L.F. |
| author_sort |
Rodríguez, H.B. |
| title |
Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose |
| title_short |
Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose |
| title_full |
Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose |
| title_fullStr |
Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose |
| title_full_unstemmed |
Eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose |
| title_sort |
eosin y triplet state as a probe of spatial heterogeneity in microcrystalline cellulose |
| url |
http://hdl.handle.net/20.500.12110/paper_00318655_v88_n4_p831_Rodriguez |
| work_keys_str_mv |
AT rodriguezhb eosinytripletstateasaprobeofspatialheterogeneityinmicrocrystallinecellulose AT romanes eosinytripletstateasaprobeofspatialheterogeneityinmicrocrystallinecellulose AT duartep eosinytripletstateasaprobeofspatialheterogeneityinmicrocrystallinecellulose AT machadoif eosinytripletstateasaprobeofspatialheterogeneityinmicrocrystallinecellulose AT vieiraferreiralf eosinytripletstateasaprobeofspatialheterogeneityinmicrocrystallinecellulose |
| _version_ |
1782024487914438656 |