Optical properties of 3,4,9,10-perylene tetracarboxylicacid (PTCA) in the presence of nanocrystallineTiO2 (nominal diameter 15 nm) have beeninvestigated in ethanol solution and in the solid state byUV–Vis absorption spectroscopy and steady-state andtime-resolved fluorescence. Experimental results showthat, in ethanol, the presence of TiO2 nanoparticles causessignificant changes in the typical absorption and fluorescencebands of PTCA and in the fluorescence relaxationtime. Similar effects are also detected in solid samples,obtained by electrospray deposition technique. Thenonlinear optical properties of the PTCA–TiO2 in ethanol solutions were investigated using the single-beam Z-scantechniques at 532 nm. It was found that, at high TiO2nanoparticles content, PTCA exhibits a reverse saturableabsorption with significant nonlinear absorption andintensity-dependent negative nonlinear refractive coefficient,indicating self-defocusing behaviour. The thirdordernonlinear susceptibility and optical limiting thresholdwere also determined. Data analysis leads consistentlyto attribute the observed behaviours to chemicaladsorptionofPTCAto theTiO2 surface both in liquid andsolid samples. Potentialities of these novel luminescentnanostructured composites as components of dye-sensitizedsolar cells or components where the nonlinearoptical behaviour is requested have been highlighted.
|Numero di pagine||10|
|Rivista||Journal of Nanoparticle Research|
|Stato di pubblicazione||Published - 2014|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Modelling and Simulation
- Condensed Matter Physics