| Title |
Grafeno sluoksnių formavimas ir modifikavimas, panaudojant lazerio spinduliuotę / |
| Translation of Title |
Formation and Modification of Graphene Layers Using Laser Irradiation. |
| Authors |
Trusovas, Romualdas |
| Full Text |
|
| Pages |
32 |
| Keywords [eng] |
Graphene ; graphite oxide reduction ; picosecond laser ; chitosan ; Congo red |
| Abstract [eng] |
In this thesis research results on application of laser irradiation for forming and modification of graphene layers are presented. Graphite oxide (GO) films on polycarbonate substrate were prepared using Hummers-Offeman method. Composition of films differed by thickness, additives and their concentration. Picosecond laser irradiation was applied to form heat conductive graphene channels. Laser power, beam scanning speed and atmosphere gases was varied during the experiments. Raman spectroscopy was applied for graphene identification. Spectroscopy measurements showed that reduction level of GO to graphene depends on various factors: applied optical power, scanning speed, concentration of GO additives (Congo Red) and ambient atmosphere. Forming of heat conductive channels was also confirmed by drop of resistance in treated films and thermo-vision measurements. Temperature dynamics of GO film after picosecond laser pulse was modeled. The results of modelling together with Raman spectroscopy measurements confirmed that optimal laser power for GO reduction is 50 mW at 100 kHz pulse repetition rate. Graphene/chitosan composite film on ITO contact was modified with picosecond laser irradiation. Raman spectroscopy showed, that laser treatment increase the disorder in composite film. EIS spectra measurements confirmed that rise of capacitance occurs in samples after laser treatment. The capacitance of modified electrodes is proportional to average power of applied laser irradiation. . |
| Dissertation Institution |
Vilniaus universitetas. |
| Type |
Summaries of doctoral thesis |
| Language |
Lithuanian |
| Publication date |
2015 |
