INVESTIGADORES
MARTINO Debora Marcela
congresos y reuniones científicas
Título:
Optical Properties and EPR Studies for Interactions between Ascorbic Acid and TiO2 Nanoparticles for Photovoltaic Applications
Autor/es:
D.M. MARTINO
Lugar:
Buenos Aires, Argentina, Abril 27 - Mayo 1
Reunión:
Conferencia; XIV International Biophysics Conference; 2002
Resumen:
<!--
/* Font Definitions */
@font-face
{font-family:Garamond;
panose-1:2 2 4 4 3 3 1 1 8 3;
mso-font-charset:0;
mso-generic-font-family:roman;
mso-font-pitch:variable;
mso-font-signature:647 0 0 0 159 0;}
@font-face
{font-family:Times;
panose-1:2 2 6 3 5 4 5 2 3 4;
mso-font-charset:0;
mso-generic-font-family:roman;
mso-font-pitch:variable;
mso-font-signature:536902279 -2147483648 8 0 511 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0cm;
margin-bottom:.0001pt;
text-align:justify;
text-indent:36.0pt;
line-height:150%;
mso-pagination:widow-orphan;
tab-stops:36.0pt 57.6pt 108.0pt 144.0pt 208.8pt 252.0pt;
font-size:11.0pt;
mso-bidi-font-size:10.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";
mso-ansi-language:EN-US;
mso-fareast-language:EN-US;}
p.texto, li.texto, div.texto
{mso-style-name:texto;
margin:0cm;
margin-bottom:.0001pt;
text-align:justify;
text-indent:28.8pt;
line-height:17.0pt;
mso-pagination:widow-orphan;
font-size:12.0pt;
mso-bidi-font-size:10.0pt;
font-family:Garamond;
mso-fareast-font-family:"Times New Roman";
mso-bidi-font-family:"Times New Roman";
mso-ansi-language:ES-TRAD;
mso-fareast-language:EN-US;}
@page Section1
{size:612.0pt 792.0pt;
margin:70.85pt 3.0cm 70.85pt 3.0cm;
mso-header-margin:36.0pt;
mso-footer-margin:36.0pt;
mso-paper-source:0;}
div.Section1
{page:Section1;}
/* List Definitions */
@list l0
{mso-list-id:2134907769;
mso-list-type:simple;
mso-list-template-ids:984907656;}
@list l0:level1
{mso-level-text:"%1\)";
mso-level-tab-stop:none;
mso-level-number-position:left;
mso-level-legacy:yes;
mso-level-legacy-indent:-14.2pt;
mso-level-legacy-space:0cm;
margin-left:0cm;
text-indent:0cm;}
ol
{margin-bottom:0cm;}
ul
{margin-bottom:0cm;}
-->
<!--
/* Font Definitions */
@font-face
{font-family:Times;
panose-1:2 2 6 3 5 4 5 2 3 4;
mso-font-charset:0;
mso-generic-font-family:roman;
mso-font-pitch:variable;
mso-font-signature:536902279 -2147483648 8 0 511 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0cm;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";
mso-ansi-language:EN-US;
mso-fareast-language:EN-US;}
@page Section1
{size:612.0pt 792.0pt;
margin:72.0pt 90.0pt 72.0pt 90.0pt;
mso-header-margin:36.0pt;
mso-footer-margin:36.0pt;
mso-paper-source:0;}
div.Section1
{page:Section1;}
-->
Electron transfer reactions
catalyzed by semiconductor nanoparticles are of great interest for their
application to solar energy conversion, degradation of pollutants, electronic
devices, synthetic processes, etc. The alteration of the surface of titanium
dioxide nanoparticles (TiO2) using ascorbic acid (AA) gives rise to
the formation of a charge transfer complex (CT). The optical properties of
modified TiO2-AA exhibited a red shift of the absorption spectra
compared to unmodified nanoparticles, increasing the use of the solar spectrum.
In these CT complexes, the charge carriers are separated instantaneously, holes
in the organic modifier (AA) and electrons in the semiconductor conduction band
(CB). Thus, the photochemistry is initiated by excitation of modifier AA
molecules with visible light, followed by electron injection in the CB of TiO2,
which afterward are transferred to acceptor molecules in solution. With the aid
of the Electron Paramagnetic Resonance technique (EPR) the time evolution of
the reduction of anthraquinone (AQ) catalyzed by TiO2 was studied.
The effect of the surface modification on the electron transfer process was
determined. The topography of the surface was analyzed using an atomic force
microscope (AFM).
