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Synthesis of nanocrystalline ZnS/TiO2 films for enhanced NO2 gas sensing

TitoloSynthesis of nanocrystalline ZnS/TiO2 films for enhanced NO2 gas sensing
Tipo di pubblicazioneArticolo su Rivista peer-reviewed
Anno di Pubblicazione2020
AutoriLaera, Anna Maria, Mirenghi L., Cassano Gennaro, Capodieci Laura, Ferrara Maria Cristina, Mazzarelli S., Schioppa M., Dimaio D., Rizzo A., Penza Michele, and Tapfer Leander
Parole chiaveCrystallographic phase, dichloromethane, II-VI semiconductors, Inorganic compounds, Magnetic semiconductors, Nanocomposite films, Nanocomposites, Nanocrystalline TiO2 films, Nanocrystals, Nitrogen oxides, Nucleation and growth, Oxide minerals, Phase structure, Scanning electron microscopy, Semiconducting zinc compounds, Semiconductor nanocrystals, Spatial dispersion, Synthetic strategies, TiO2 nanoparticles, Titanium dioxide, Wide band gap semiconductors, X-ray diffraction measurements, Zinc, Zinc sulfide, Zinc-blende structures, ZnS nanoparticles

Highly porous nanocrystalline TiO2 films were sensitized with ZnS semiconductor nanocrystals by using a three-step facile strategy. The TiO2 matrices were firstly impregnated with the zinc bis(benzyl)thiol precursor that, unlike many other metal chalcogenides, is easily dispersible in the most common organic solvents. In the second step of the adopted synthetic strategy, the TiO2 impregnated with zinc thiolate was annealed at 250 °C in order to induce nucleation and growth of ZnS nanocrystals inside the porous matrices as well as on the film surface. A final cleavage in dichloromethane allowed us to remove all residual organic reagents and products. The size of the ZnS nanocrystals can be tuned by variation of the annealing time as shown by X-ray diffraction measurements, without changing the crystallographic phase structure (zincblende structure). Scanning electron microscopy analysis showed a random spatial dispersion of the ZnS nanocrystals and no remarkable aggregation was observed. The sensor device based on TiO2-ZnS nanocomposite was able to detect NO2 gas at 270 °C down to 1 ppm with negligible response towards reducing gases (CO, CH4). Compared to bare TiO2 film, the TiO2-ZnS nanocomposite shows higher sensitivity and lower recovery time towards an oxidant NO2 gas. © 2020


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Citation Key 20.500.12079_57105