Figure 7 TEM selleck images of CdS/MEH-PPV nanocomposites. Obtained
at 185°C starting from a solution with a weight/weight ratio precursor/polymer of 1:4 (a, b) and from a solution with a weight/weight ratio precursor/polymer of 2:3 (c, d). Figure 8a,b shows the high-resolution images of single CdS NCs. The nanoparticles are highlighted (marked by dashed line) in order to better visualize the CdS NCs within the polymer matrix. The (100) and (101) lattice fringes of the wurtzite phase of CdS are well observed and are distinct from the amorphous matrix. The particles are of VX-689 mouse spherical shape, and the average diameter is about 3 to 4 nm. Figure 8 High-resolution TEM images of CdS NCs (marked by dashed lines). Exhibiting (100) and (101) lattice fringes in (a) and (b), respectively. The NCs are of almost spherical in shape and diameter between 3 and 4 nm. Rheological properties of the nanocomposite films Figure 9 shows the viscosity of MEH-PPV and nanocomposite CdS/MEH-PPV with a relative weight ratio of 1:4 depending upon the values of shear rate. At low shear rate, both materials show a Newtonian behaviour, while at high shear rate, the viscosity linearly
decreases as a non-Newtonian fluid described in Carreau model . The fitting AMN-107 order of the experimental data using the Carraeu model yields a viscosity of η 0 = 5.745 × 104 Pa·s and η 0 = 5.498 × 104 Pa·s, for the pristine polymer and CdS/MEH-PPV nanocomposite, respectively. In addition, the transition from a Newtonian to a non-Newtonian behaviour occurs at a viscosity of (a) η 0 = 4.09 × 104 Pa·s and shear rate , and (b) η 0 = 5.213 × 104 Pa·s and shear rate , respectively. Figure 9 Rheological measurements of pristine MEH-PPV and CdS/MEH-PPV nanocomposites. With a weight/weight ratio between precursor and polymer of 1:4 carried out at 200°C. These results indicate that the inclusion of NCs into the polymer matrix does not significantly alter the polymer mafosfamide resistance to deformation. Applications in the field of large-area, flexible, low-cost solar cells require to preserve the nanoflow material rheology
to allow the developing of fabrication process based on spinning or soft moulding lithography. The rheological measurements complete the characterization of prepared CdS/MEH-PPV hybrid nanocomposites. All data acquired by absorption spectroscopy, X-ray diffraction and TEM show the growth of CdS NCs with a regular spherical shape, a narrow size distribution and a homogenous dispersion inside the polymer. The use of 1-methylimidazole ligand to improve the solubility of Cd(SBz)2 has allowed to obtain clear solutions of the complex [Cd(SBz)2]2·MI and MEH-PPV in chloroform, suitable to prepare thin solid film using the cheap and easy technique of spin coating. The CdS NCs size grows from 2.8 to 3.5 nm in the temperature range 175°C to 200°C, demonstrating a slow and controlled diffusion of Cd(SBz)2 molecules inside the matrix.