Tuning the energetics and tailoring the optical properties of silver clusters confined in zeolites

The integration of metal atoms and clusters in well-defined dielectric cavities is a powerful strategy to impart new properties to them that depend on the size and geometry of the confined space as well as on metal-host electrostatic interactions. Here, we unravel the dependence of the electronic properties of metal clusters on space confinement by studying the ionization potential of silver clusters embedded in four different zeolite environments over a range of silver concentrations. Extensive characterization reveals a strong influence of silver loading and host environment on the cluster ionization potential, which is also correlated to the cluster's optical and structural properties. Through fine-tuning of the zeolite host environment, we demonstrate photoluminescence quantum yields approaching unity. This work extends our understanding of structure property relationships of small metal clusters and applies this understanding to develop highly photoluminescent materials with potential applications in optoelectronics and bioimaging

Energy Band Structure Studies Of Zinc-Blende GaAs and InAs

A self-consistent calculation of the structural and electronic properties of zinc blende GaAs and InAs has been carried out. The calculations were done using the full potential-linearized augmented plane wave (FPLAPW) method within the density functional theory (DFT). The exchange-correlation energy used is the generalized gradient approximation as parameterized by Perdew-Burke and Ernzerhof (PBEGGA). Energy band structures, density of states and structural parameters of all the compounds are presented and discussed in context with available theoretical and experimental studies. Our results show that the energy band gaps of the semiconductors are underestimated. But overall our results show reasonable agreement with previous results even though sufficient experimental results are not available for more realistic comparison