General p-i-n solar cell structures are suitable hosts for regions where quantum effects might occur; excess photo-carriers can be developed in quantum traps (quantum wells) grown along the direction of the cell (from p to n region). The cell absorbs at two different wavelengths (a) the host (Ehost=hc/λhost band-gap) and (b) the optical gap wavelength (Esolar-photon=hc/λoptical gap). The optica...

In the present work, we report studies on optical and structural phenomenon in as-deposited thin films composed of aligned nanorods of amorphous SexTe100-x (x = 3, 6, 9, and 12). In structural studies, field emission scanning electron microscopic (FESEM) images suggest that these thin films contain high yield of aligned nanorods. These nanorods show a completely amorphous nature, which is verif...

Incorporating biphenyls as co-monomers in electron-deficient diketopyrrolopyrrole (DPP) conjugated polymers enables widening the optical band gap to 1.70 eV. Power conversion efficiencies of 3.7-5.7% and high open-circuit voltages of 0.80-0.93 V are obtained in solar cells based on these wide band gap DPP polymers.

by means of first principles calculations we show that both rutile and anatase phases of bulk tio2 doped by s, se or pb can display substantial decreasing in the band gap (up to 50%), while doping by zr does not sizably affect the band-gap value. moreover, the absorption edge is shifted (up to 1 ev) to the lower energy range in the case of tio2 doped by s or pb that opens a way to enhancing of ...

An optical study of the band structure of both silicon–silica composite and silicon inverse opals is presented. The study is aimed at demonstrating the development of a full photonic band gap for a system already revealed as paradigmatic. The characterization is based on the comparison between the band structure calculations and optical reflectance spectroscopy experiments. This study is carrie...

In this study, density functional theory is used to evaluate the electronic structure of the antimony chalcogenide series. Analysis of the electronic density of states and charge density shows that asymmetric density, or ‘lone pairs’, form on the Sb cations in the distorted oxide, sulphide and selenide materials. The asymmetric density progressively weakens down the series, due to the increase ...

The measured optical and transport properties of singlecrystal SrTiO3 have been determined as a function of oxidation and reduction using spectroscopic ellipsometry, Hall and resistivity measurements. A decrease in the valence to conduction band transitions across the band gap, from O 2p to Ti 3d states, is observed by decreases in both the index of refraction and the extinction coefficient at ...

The structural and optical properties of polyvinyl alcohol (PVA) doped with different concentrations (0, 0.15, 0.5, 1, 2, 2.5, and 3 wt %) of ZnO nanoparticles were studied. ZnO nanoparticles were prepared by the solgel methode, and nanocomposite films were prepared using the solution casting methode. Nanocomposites films were characterized by X-ray diffraction (XRD), Fourier Transformer Infrar...