Designing transparent nanophotonic gratings for ultra-thin solar cells.

Integration of a rear surface nanophotonic grating can increase photocurrent in ultra-thin solar cells. Transparent gratings formed of dielectric materials and high bandgap semiconductors can offer efficient diffraction with lower parasitic absorption than more widely studied metal/dielectric equivalents. In these systems, the maximum photocurrent which can be obtained for a grating made of a given combination of materials is shown to follow a simple empirical model based on the optical constants of these materials and independent of grating dimensions.

Assessing the Nature of the Distribution of Localised States in Bulk GaAsBi.

A comprehensive assessment of the nature of the distribution of sub band-gap energy states in bulk GaAsBi is presented using power and temperature dependent photoluminescence spectroscopy. The observation of a characteristic red-blue-red shift in the peak luminescence energy indicates the presence of short-range alloy disorder in the material. A decrease in the carrier localisation energy demonstrates the strong excitation power dependence of localised state behaviour and is attributed to the filling of energy states furthest from the valence band edge.

Blue-Green Color Tunable Solution Processable Organolead Chloride-Bromide Mixed Halide Perovskites for Optoelectronic Applications.

Solution-processed organo-lead halide perovskites are produced with sharp, color-pure electroluminescence that can be tuned from blue to green region of visible spectrum (425-570 nm). This was accomplished by controlling the halide composition of CH3NH3Pb(BrxCl1-x)3 [0 ≤ x ≤ 1] perovskites. The bandgap and lattice parameters change monotonically with composition.

Controlling self-assembly of reduced graphene oxide at the air-water interface: quantitative evidence for long-range attractive and many-body interactions.

Industrial-scale applications of two-dimensional materials are currently limited due to lack of a cost-effective and controlled synthesis method for large-area monolayer films. Self-assembly at fluid interfaces is one promising method. Here, we present a quantitative analysis of the forces governing reduced graphene oxide (rGO) assembly at the air-water interface using two unique approaches: area-based radial distribution functions and a theoretical Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction potential for disks interacting edge-to-edge.