Controllable lasing performance in solution-processed organic-inorganic hybrid perovskites.

Solution-processed organic-inorganic perovskites are fascinating due to their remarkable photo-conversion efficiency and great potential in the cost-effective, versatile and large-scale manufacturing of optoelectronic devices. In this paper, we demonstrate that the perovskite nanocrystal sizes can be simply controlled by manipulating the precursor solution concentrations in a two-step sequential deposition process, thus achieving the feasible tunability of excitonic properties and lasing performance in hybrid metal-halide perovskites. The lasing threshold is at around 230 μJ cm in this solution-processed organic-inorganic lead-halide material, which is comparable to the colloidal quantum dot lasers.

Plasmonic nanostructures for light trapping in organic photovoltaic devices.

Over the past decade, we have witnessed rapid advances in the development of organic photovoltaic devices (OPVs). At present, the highest level of efficiency has surpassed 10%, suggesting that OPVs have great potential to become competitive with other thin-film solar technologies. Because plasmonic nanostructures are likely to further improve the efficiency of OPVs, this Article reviews recent progress in the development of metal nanostructures for triggering plasmonic effects in OPVs.

High-performance flexible waveguiding photovoltaics.

The use of flat-plane solar concentrators is an effective approach toward collecting sunlight economically and without sun trackers. The optical concentrators are, however, usually made of rigid glass or plastics having limited flexibility, potentially restricting their applicability. In this communication, we describe flexible waveguiding photovoltaics (FWPVs) that exhibit high optical efficiencies and great mechanical flexibility.

A perceptually tuned watermarking scheme for color images.

Transparency and robustness are two conflicting requirements demanded by digital image watermarking for copyright protection and many other purposes. A feasible way to simultaneously satisfy the two conflicting requirements is to embed high-strength watermark signals in the host signals that can accommodate the distortion due to watermark insertion as part of perceptual redundancy. The search of distortion-tolerable host signals for watermark insertion and the determination of watermark strength are hence crucial to the realization of a transparent yet robust watermark.