Ab initiocalculations of structural and electronic properties of CdTe clusters

Abstract

We present results of a study of small stoichiometric CdnT en (1≤n≤6) clusters and few medium sized non-stoichiometric CdmT en [(m, n = 13, 16, 19); (m =n)] clusters using the Density Functional formalism and projector augmented wave method within the generalized gradient approximation. Structural properties viz. geometry, bond length, symmetry and electronic properties like HOMO-LUMO gap, binding energy, ionization potential and nature of bonding etc. have been analyzed. Medium sized non-stoichiometric clusters were considered as fragments of the bulk with T d symmetry. It was observed that upon relaxation, the symmetry changes for the Cd-rich clusters whereas the Te-rich clusters retain their symmetry. The Cd-rich clusters develop a HOMO-LUMO gap due to relaxation whereas there is no change in the HOMO-LUMO gap of the Te-rich clusters. Thus, the symmetry of a cluster seems to be an important factor in determining the HOMO-LUMO gap.

Hydride Generation for Headspace Solid-Phase Extraction with CdTe Quantum Dots Immobilized on Paper for Sensitive Visual Detection of Selenium

“…The structures of these clusters are shown in Figure 3, similar to previous studies. 43,44 The configurations and adsorption energies are also summarized in Figure 3 Previous studies reported 45,46 that a Cd−thiol complex surface layer was created as a shell around the CdTe QDs core to occupy the surface sites and to passivate the QDs. In addition, the binding force of Cd−Se bond was much greater than that of Cd-thiol.…”

Theoretical simulation of CdTe nanocrystals in aqueous synthesis

“…1 and corresponding characters are listed in Table 1. Clearly, Cd 3 Te 3 cluster is a six-atom ring, which has slightly longer bond length (2.770 Å ) than those reported by Bhattacharya and Kshirsagar [19]. This ring is planar but its conformation is not similar to benzene ring.…”

“…Sequentially, Te-Cd-ligand clusters are calculated to further discuss the bond and spectrum qualities of CdTe nanocrystals. In a word, the previous report [19,34] emphasized the conformations and HOMO-LUMO gaps of different CdTe clusters. They also investigated the characters of Te-rich and Cd-rich clusters.…”

“…This report allowed one to model uncoordinated CdSe clusters and generalize the calculations for ligandcoordinated clusters. Bhattacharya and Kshirsagar [19] investigated Cd n Te n (1 B n B 6) clusters and got many structures with ab initio method. Besides, there were many other papers to investigate the clusters of II-V semiconductor in theory [20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Simulating Interface Growth and Defect Generation in CZT – Simulation State of the Art and Known Gaps

“…There have been many studies of defect and absorption energetics of CdTe and CZT using DFT [230,[327][328][329][330][331][332][333][334][335][336][337][338][339][340][341][342][343][344]. Even though DFT has been very successful in predicting structures, properties and reactivities for a wide variety of molecular and solid-state systems, the accuracy of the defect energies from DFT has not been rigorously validated from experiment or higher levels of ab initio theory.…”