Giant Optical Anisotropy in 2D Metal-Organic Chalcogenates.

Optical anisotropy is a fundamental attribute of some crystalline materials and is quantified via birefringence. A birefringent crystal gives rise to not only asymmetrical light propagation but also attenuation along two distinct polarizations, a phenomenon called linear dichroism (LD). Two-dimensional (2D) layered materials with high in-plane and out-of-plane anisotropy have garnered interest in this regard.

Brightening deep-blue perovskite light-emitting diodes: A path to Rec. 2020.

Deep-blue perovskite light-emitting diodes (PeLEDs) of high purity are highly sought after for next-generation displays complying with the Rec. 2020 standard. However, mixed-halide perovskite materials designed for deep-blue emitters are prone to halide vacancies, which readily occur because of the low formation energy of chloride vacancies.

Highly Efficient Vacuum-Evaporated CsPbBr Perovskite Light-Emitting Diodes with an Electrical Conductivity Enhanced Polymer-Assisted Passivation Layer.

Highly efficient vacuum-deposited CsPbBr perovskite light-emitting diodes (PeLEDs) are demonstrated by introducing a separate polyethylene oxide (PEO) passivation layer. A CsPbBr film deposited on the PEO layer via thermal co-evaporation of CsBr and PbBr exhibits an almost 50-fold increase in photoluminescence quantum yield intensity compared to a reference sample without PEO. This enhancement is attributed to the passivation of interfacial defects of the perovskite, as evidenced by temperature-dependent photoluminescence measurements.