Collective Interactions of Quantum-Confined Excitons in Halide Perovskite Nanocrystal Superlattices.

Collective optical properties can emerge from an ordered ensemble of emitters due to interactions between the individual units. Superlattices of halide perovskite nanocrystals exhibit collective light emission, influenced by dipole-dipole interactions between simultaneously excited nanocrystals. This coupling changes both the emission energy and rate compared to the emission of uncoupled nanocrystals.

Tuning the Colloidal Softness of CsPbBr Nanocrystals for Homogeneous Superlattices.

Perovskite nanocrystal superlattices (NC SLs), made from millions of ordered crystals, support collective optoelectronic phenomena. Coupled NC emitters are highly sensitive to the structural and spectral inhomogeneities of the NC ensemble. Free electrons in scanning electron microscopy (SEM) are used to probe the cathodoluminescence (CL) properties of CsPbBr SLs with a ∼20 nm spatial resolution.

The Role Silver Nanoparticles Plays in Silver-Based Double-Perovskite Nanocrystals.

Lead-free double perovskites are studied as an optional replacement to lead halide perovskites in optoelectronic applications. Recently, double-perovskite materials in which two divalent lead cations are replaced with an Ag and a trivalent cation have been demonstrated. The presence of a reactive silver cation and observations of metallic silver nanodecorations raised concerns regarding the stability and applicability of these materials.

Electromagnetic impedance tomography (EMIT): a new method for impedance imaging.

We propose a new impedance imaging method, electromagnetic impedance tomography (EMIT), in which the boundary electric potential measurements in electrical impedance tomography (EIT) are augmented by measurements of the exterior magnetic field induced by the currents excited in the object by the standard EIT procedures. These magnetic measurements can be obtained reliably and inexpensively by simple pickup coils located around the imaged cross section. We derive expressions for the forward problem and for the Jacobian of the measurements, and propose an iterative reconstruction algorithm using a squared error cost function.