Silicon nanoparticle photophysics and singlet oxygen generation
The effect of molecular oxygen and water on the blue photoluminescence of silicon nanoparticles synthesized by anodic oxidation of silicon wafers and surface functionalized with 2-methyl 2-propenoic acid methyl ester is investigated. The particles of 3 ± 1 nm diameter and a surface composition of Si...
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todo:paper_07437463_v26_n13_p10953_LlansolaPortoles2023-10-03T15:38:41Z Silicon nanoparticle photophysics and singlet oxygen generation Llansola Portolés, M.J. David Gara, P.M. Kotler, M.L. Bertolotti, S. San Román, E. Rodríguez, H.B. Gonzalez, M.C. Aqueous solutions Aqueous suspensions Blue photoluminescence Emission quantum yield Functionalized Heavy atom effects Low energies Low-temperature luminescence Luminescence decay time Luminescence intensity Methyl esters Methylviologen Photophysics Physisorbed Room temperature Silicon nanoparticles Singlet molecular oxygen Singlet oxygen generation Singlet state Spectrum features Surface compositions Time-resolved Toluene suspensions Wavelength ranges Adsorption Anodic oxidation Dissolution Energy transfer Esters Excitons Gas generators Luminescence Molecular oxygen Nanoparticles Plasma diagnostics Semiconducting silicon compounds Silicon oxides Suspensions (fluids) Toluene Silicon wafers nanoparticle silicon singlet oxygen article chemistry infrared spectroscopy luminescence nanotechnology pH photochemistry Hydrogen-Ion Concentration Luminescence Nanoparticles Nanotechnology Photochemistry Silicon Singlet Oxygen Spectroscopy, Fourier Transform Infrared The effect of molecular oxygen and water on the blue photoluminescence of silicon nanoparticles synthesized by anodic oxidation of silicon wafers and surface functionalized with 2-methyl 2-propenoic acid methyl ester is investigated. The particles of 3 ± 1 nm diameter and a surface composition of Si3O6(C5O2H 8) exhibit room-temperature luminescence in the wavelength range 300-600 nm upon excitation with 300-400 nm light. The luminescence shows vibronic resolution and high quantum yields in toluene suspensions, while a vibronically unresolved spectrum and lower emission quantum yields are observed in aqueous suspensions. The luminescence intensity, though not the spectrum features, depends on the presence of dissolved O2. Strikingly, the luminescence decay time on the order of 1 ns does not depend on the solvent or on the presence of O2. To determine the mechanisms involved in these processes, time-resolved and steady-state experiments are performed. These include low-temperature luminescence, heavy atom effect, singlet molecular oxygen (1O2) phosphorescence detection, reaction of specific probes with 1O2, and determination of O 2 and N2 adsorption isotherms at 77 K. The results obtained indicate that physisorbed O2 is capable of quenching nondiffusively the particle luminescence at room temperature. The most probable mechanism for 1O2 generation involves the energy transfer from an exciton singlet state to O2 to yield an exciton triplet of low energy (<0.98 eV) and 1O2. In aqueous solutions, excited silicon nanoparticles are able to reduce methylviologen on its surface. © 2010 American Chemical Society. Fil:Kotler, M.L. 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. Fil:Rodríguez, H.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Gonzalez, M.C. 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_07437463_v26_n13_p10953_LlansolaPortoles |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Aqueous solutions Aqueous suspensions Blue photoluminescence Emission quantum yield Functionalized Heavy atom effects Low energies Low-temperature luminescence Luminescence decay time Luminescence intensity Methyl esters Methylviologen Photophysics Physisorbed Room temperature Silicon nanoparticles Singlet molecular oxygen Singlet oxygen generation Singlet state Spectrum features Surface compositions Time-resolved Toluene suspensions Wavelength ranges Adsorption Anodic oxidation Dissolution Energy transfer Esters Excitons Gas generators Luminescence Molecular oxygen Nanoparticles Plasma diagnostics Semiconducting silicon compounds Silicon oxides Suspensions (fluids) Toluene Silicon wafers nanoparticle silicon singlet oxygen article chemistry infrared spectroscopy luminescence nanotechnology pH photochemistry Hydrogen-Ion Concentration Luminescence Nanoparticles Nanotechnology Photochemistry Silicon Singlet Oxygen Spectroscopy, Fourier Transform Infrared |
| spellingShingle |
Aqueous solutions Aqueous suspensions Blue photoluminescence Emission quantum yield Functionalized Heavy atom effects Low energies Low-temperature luminescence Luminescence decay time Luminescence intensity Methyl esters Methylviologen Photophysics Physisorbed Room temperature Silicon nanoparticles Singlet molecular oxygen Singlet oxygen generation Singlet state Spectrum features Surface compositions Time-resolved Toluene suspensions Wavelength ranges Adsorption Anodic oxidation Dissolution Energy transfer Esters Excitons Gas generators Luminescence Molecular oxygen Nanoparticles Plasma diagnostics Semiconducting silicon compounds Silicon oxides Suspensions (fluids) Toluene Silicon wafers nanoparticle silicon singlet oxygen article chemistry infrared spectroscopy luminescence nanotechnology pH photochemistry Hydrogen-Ion Concentration Luminescence Nanoparticles Nanotechnology Photochemistry Silicon Singlet Oxygen Spectroscopy, Fourier Transform Infrared Llansola Portolés, M.J. David Gara, P.M. Kotler, M.L. Bertolotti, S. San Román, E. Rodríguez, H.B. Gonzalez, M.C. Silicon nanoparticle photophysics and singlet oxygen generation |
| topic_facet |
Aqueous solutions Aqueous suspensions Blue photoluminescence Emission quantum yield Functionalized Heavy atom effects Low energies Low-temperature luminescence Luminescence decay time Luminescence intensity Methyl esters Methylviologen Photophysics Physisorbed Room temperature Silicon nanoparticles Singlet molecular oxygen Singlet oxygen generation Singlet state Spectrum features Surface compositions Time-resolved Toluene suspensions Wavelength ranges Adsorption Anodic oxidation Dissolution Energy transfer Esters Excitons Gas generators Luminescence Molecular oxygen Nanoparticles Plasma diagnostics Semiconducting silicon compounds Silicon oxides Suspensions (fluids) Toluene Silicon wafers nanoparticle silicon singlet oxygen article chemistry infrared spectroscopy luminescence nanotechnology pH photochemistry Hydrogen-Ion Concentration Luminescence Nanoparticles Nanotechnology Photochemistry Silicon Singlet Oxygen Spectroscopy, Fourier Transform Infrared |
| description |
The effect of molecular oxygen and water on the blue photoluminescence of silicon nanoparticles synthesized by anodic oxidation of silicon wafers and surface functionalized with 2-methyl 2-propenoic acid methyl ester is investigated. The particles of 3 ± 1 nm diameter and a surface composition of Si3O6(C5O2H 8) exhibit room-temperature luminescence in the wavelength range 300-600 nm upon excitation with 300-400 nm light. The luminescence shows vibronic resolution and high quantum yields in toluene suspensions, while a vibronically unresolved spectrum and lower emission quantum yields are observed in aqueous suspensions. The luminescence intensity, though not the spectrum features, depends on the presence of dissolved O2. Strikingly, the luminescence decay time on the order of 1 ns does not depend on the solvent or on the presence of O2. To determine the mechanisms involved in these processes, time-resolved and steady-state experiments are performed. These include low-temperature luminescence, heavy atom effect, singlet molecular oxygen (1O2) phosphorescence detection, reaction of specific probes with 1O2, and determination of O 2 and N2 adsorption isotherms at 77 K. The results obtained indicate that physisorbed O2 is capable of quenching nondiffusively the particle luminescence at room temperature. The most probable mechanism for 1O2 generation involves the energy transfer from an exciton singlet state to O2 to yield an exciton triplet of low energy (<0.98 eV) and 1O2. In aqueous solutions, excited silicon nanoparticles are able to reduce methylviologen on its surface. © 2010 American Chemical Society. |
| format |
JOUR |
| author |
Llansola Portolés, M.J. David Gara, P.M. Kotler, M.L. Bertolotti, S. San Román, E. Rodríguez, H.B. Gonzalez, M.C. |
| author_facet |
Llansola Portolés, M.J. David Gara, P.M. Kotler, M.L. Bertolotti, S. San Román, E. Rodríguez, H.B. Gonzalez, M.C. |
| author_sort |
Llansola Portolés, M.J. |
| title |
Silicon nanoparticle photophysics and singlet oxygen generation |
| title_short |
Silicon nanoparticle photophysics and singlet oxygen generation |
| title_full |
Silicon nanoparticle photophysics and singlet oxygen generation |
| title_fullStr |
Silicon nanoparticle photophysics and singlet oxygen generation |
| title_full_unstemmed |
Silicon nanoparticle photophysics and singlet oxygen generation |
| title_sort |
silicon nanoparticle photophysics and singlet oxygen generation |
| url |
http://hdl.handle.net/20.500.12110/paper_07437463_v26_n13_p10953_LlansolaPortoles |
| work_keys_str_mv |
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| _version_ |
1807316634780565504 |