Investigations of Al:CdS/PVA nanocomposites: A joint theoretical and experimental approach

• Highly c-axis oriented Al doped CdS/PVA nanocomposites were deposited on glass slide using aqueous solutions.
• Optical band gap reduced on Al doping.
• DFT is used to simulate atomistic models of inorganic–organic hybrid nanocomposites.
• FMOs used to study charge transfer behaviour between inorganic and organic moieties.

In the present work we investigate the aluminium doped cadmium sulphide (Al:CdS) nanoparticles embedded in polyvinyl alcohol (PVA) matrix by chemical route and density functional theory (DFT) based simulations. Supertetrahedron (Tn) cluster models are considered for the simulation of CdS nanoparticles. Using DFT simulations on Tn clusters, we observe that band gap of ligated clusters is slightly more as compare to bare clusters. This indicates the ability of organic ligands (PVA) to open the band gap of inorganic CdS nanoclusters. Negative value of binding energy indicates the stability of the inorganic–organic hybrid system. Frontier molecular orbitals (FMOs) indicate the charge transfer between organic and inorganic moieties which provides stability and longevity to nanoparticles, a prime function of ligands in nanocomposites. Absorption spectra of pure and doped clusters are calculated using time dependent density functional theory (TDDFT). CdS/PVA and Al:CdS/PVA samples are synthesized at room temperature by chemical method. Their structure, size and band gap is characterized by XRD, TEM, FTIR and UV spectroscopy. Optical band gap values as observed experimentally are in agreement with simulated TDDFT results.

Figure optionsDownload as PowerPoint slide