Energy transfer among dyes on particulate solids
Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00318655_v82_n1_p200_Rodriguez |
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todo:paper_00318655_v82_n1_p200_Rodriguez2023-10-03T14:41:35Z Energy transfer among dyes on particulate solids Rodriguez, H.B. Iriel, A. San Román, E. cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure MB builds up dimeric species on cellulose even at 2 × 10 -8 mol g -1, addition of 2.05 × 10 -7 mol g -1 Pheo largely inhibits aggregation up to nearly 10 -6 mol g -1 MB. At the same time, the absorption spectrum of monomeric MB in the presence of Pheo differs from the spectrum in pure cellulose. Both effects reveal a strong influence of Pheo on the medium properties. A model relying entirely on experimental data is developed, through which energy transfer efficiencies can be calculated for thin and thick layers of dye-loaded cellulose. At the largest concentration of MB assuring no dye aggregation, nonradiative energy transfer efficiencies reach a maximum value of nearly 40%. This value is quite high, taking into account the low fluorescence quantum yield of Pheo, Φ = 0.21, and results from the existence of high local concentrations of the acceptor within the supporting material. These results show that large energy transfer rates can exist in a system devoid of any special molecular organization. © 2006 American Society for Photobiology. Fil:Rodriguez, H.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Iriel, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:San Román, E. 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_v82_n1_p200_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 chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry |
| spellingShingle |
cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry Rodriguez, H.B. Iriel, A. San Román, E. Energy transfer among dyes on particulate solids |
| topic_facet |
cellulose chlorophyll coloring agent drug derivative methylene blue pheophorbide a chemistry conference paper energy transfer spectrophotometry Cellulose Chlorophyll Coloring Agents Energy Transfer Methylene Blue Spectrophotometry |
| description |
Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure MB builds up dimeric species on cellulose even at 2 × 10 -8 mol g -1, addition of 2.05 × 10 -7 mol g -1 Pheo largely inhibits aggregation up to nearly 10 -6 mol g -1 MB. At the same time, the absorption spectrum of monomeric MB in the presence of Pheo differs from the spectrum in pure cellulose. Both effects reveal a strong influence of Pheo on the medium properties. A model relying entirely on experimental data is developed, through which energy transfer efficiencies can be calculated for thin and thick layers of dye-loaded cellulose. At the largest concentration of MB assuring no dye aggregation, nonradiative energy transfer efficiencies reach a maximum value of nearly 40%. This value is quite high, taking into account the low fluorescence quantum yield of Pheo, Φ = 0.21, and results from the existence of high local concentrations of the acceptor within the supporting material. These results show that large energy transfer rates can exist in a system devoid of any special molecular organization. © 2006 American Society for Photobiology. |
| format |
JOUR |
| author |
Rodriguez, H.B. Iriel, A. San Román, E. |
| author_facet |
Rodriguez, H.B. Iriel, A. San Román, E. |
| author_sort |
Rodriguez, H.B. |
| title |
Energy transfer among dyes on particulate solids |
| title_short |
Energy transfer among dyes on particulate solids |
| title_full |
Energy transfer among dyes on particulate solids |
| title_fullStr |
Energy transfer among dyes on particulate solids |
| title_full_unstemmed |
Energy transfer among dyes on particulate solids |
| title_sort |
energy transfer among dyes on particulate solids |
| url |
http://hdl.handle.net/20.500.12110/paper_00318655_v82_n1_p200_Rodriguez |
| work_keys_str_mv |
AT rodriguezhb energytransferamongdyesonparticulatesolids AT iriela energytransferamongdyesonparticulatesolids AT sanromane energytransferamongdyesonparticulatesolids |
| _version_ |
1807315730476040192 |