The particle size distribution and the average particle sizes (<D>) for the samples diluted in water and isopropanol are shown in Fig. and Fig. , respectively. The <D> size of Sn(S0,5Se0,5)2 samples diluted in isopropanol are clearly higher compared to the samples diluted in water. In addition, it is worth noting that this sample shows a tendency to form agglomerates, as highlighted in the insets of Fig. indicate that the balance between selenium and sulfur ions in the crystal structure, may lead to an electrostatic interaction between these particles, that is favored in the presence of isopropanol. In the annealed samples, the <D> size of Sn(S0,5Se0,5)2 decreases, since the increase in the temperature promotes the separation of agglomerates. Then, the gas sensor measurements were performed in the samples diluted in isopropanol, once they showed better dispersion when dropped into the electrode sensor device, and this step is crucial to obtain a homogeneous coating that ensure good gas sensing measurements.