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| Author(s): |
Tarcísio Rocha Figueredo
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT) |
| Defense date: | 2014-02-14 |
| Examining board members: |
Cleber Renato Mendonça;
Francisco Eduardo Gontijo Guimarães;
Ricardo Elgul Samad
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| Advisor: | Cleber Renato Mendonça |
| Abstract | |
This work investigated the photodegradation of Rhodamine-B assisted by Titanium Dioxide semiconductor catalyst, using as irradiation source a Ti:Sapphire laser system delivering 40 fs pulses. The laser pulses were spectrally shaped (sinusoidal modulation), generating pulse trains whose separation was chosen to be resonant with an intense catalysts Raman mode. The Rh-B photodegradation was monitored by two photon excited fluorescence measurements. We have not observed dye photodegradation by the ultrashort pulses irradiation, in the absence of the catalyst, neither with the shortest pulse obtained, nor with pulse trains. Nevertheless, we observed a decrease in the excitation light scattering due to the Titanium Dioxide nanoparticles. Such process was studied by analyzing the influence of sinusoidal spectral phase mask in the signal. The results indicate a relationship between femtosecond pulse irradiation and the breaking of nanoparticles clusters, which was also corroborated by scanning electron microscopy measurements. (AU) | |
| FAPESP's process: | 12/02553-4 - Coherent control of TiO2-mediated photocatalysis induced by fs-laser pulses |
| Grantee: | Tarcísio Rocha Figueredo |
| Support Opportunities: | Scholarships in Brazil - Master |