Reduction of the wavelength in on-chip light circuitry is critically important not only for the sake of keeping up with Moore’s law for photonics but also for reaching toward the spectral ranges of...

Perovskite–Gallium Phosphide Platform for Reconfigurable Visible-Light Nanophotonic Chip

Structural, electronic and optical properties for halide double perovskites compounds K2GeSnBr6 and K2GeSnI6 are studied in this work. Based on the (FP-LAPW) method, the previous properties are treated within the (GGA-PBE) and the (mBJ-GGA) approximations. The results show that these compounds are stable in the non-magnetic phase (NM). Electronic properties indicate that these compounds have a semiconductor behavior with a direct band gap. The calculated formation energy and cohesive energy indicate that these alloys have good chemical stability. High absorption coefficient and high reflectivity prove that these materials are appropriates for optoelectronic applications, including solar and photovoltaic cells.

Lead-free Semiconductors with High Absorption: Insight into the Optical Properties of K2GeSnBr6 and K2GeSnI6 Halide Double Perovskites

Full Heusler alloys, with high absorption coefficient, insight into the optical properties of Li2CaC and Li2SrC

Bismuth-based perovskites are attracting intense scientific interest due to low toxicity and excellent moisture stability compared to lead-based analogues. However, high exciton binding energy, poor charge carrier separation, and transport efficiencies lower their optoelectronic performances. To address these issues, we have integrated an electronically active organic cation, naphthalimide ethylammonium, between the [BiI52-]n chains via crystal engineering to form a novel perovskite-like material (naphthalimide ethylammonium)2BiI5 (NBI). Single crystal analysis revealed a one-dimensional quantum-well structure for NBI in which inter-inorganic well electronic coupling is screened by organic layers. It exhibited anisotropic photoconductivity and long-lived charge carriers with milliseconds lifetime, which is higher than that of CH3NH3PbI3. Density functional theory calculations confirmed type-IIa band alignment between organic cations and inorganic chains, allowing the former to electronically contribute to the overall charge transport properties of the material.

Anisotropic Photoconductivity and Long-Lived Charge Carriers in Bismuth-Based One-Dimensional Perovskite with Type-IIa Band Alignment.

https://iopscience.iop.org/article/10.1149/2162-8777/abd48a/pdf

Synthesis of CsPbBr3 and CsPbBrXI(3-X) Films by Spray-Coating Technique

Photophysical properties of halide perovskite CsPb(Br1-xIx)3 thin films and nanowires

Organic–inorganic perovskites with a mixed anion composition are widely used in solar cells, light-emitting diodes, and nanophotonic structures. Light nanosources based on resonant perovskite nanoparticles are of particular interest. However, perovskites with such a composition demonstrate the light-induced segregation of anions, which leads to a reversible dynamic rearrangement of the optical properties of a material and photoluminescence spectra. In this work, the photoinduced process of change in optical properties in resonant hybrid perovskite nanoparticles with a mixed anion composition (MAPbBr1.5I1.5, where MA = NH3CH
 3
 +
 ) has been studied. Comparison with a similar process in a perovskite thin film with a similar composition has shown that the photoinduced migration of halogen ions in a nanoparticle occurs cyclically. This is due to the competition of two processes: the concentration of ions near the boundaries of the particle and migration caused by the gradient of the density of light-generated electron–hole pairs. This effect in resonant nanoparticles makes it possible to obtain optically tunable nanoantennas.

E. Yu Tiguntseva

Papers

Photophysical properties of halide perovskite CsPb(Br1-xIx)3 thin films and nanowires

Photoinduced Migration of Ions in Optically Resonant Perovskite Nanoparticles

Fabrication of halide-perovskite resonant microcylinders by nanoimprint lithography