Equilibrium densities of intrinsic defects in transition metal diselenides of molybdenum and tungsten.

Point defects are thermodynamically stabilized in all crystalline materials, with increased densities negatively impacting the properties and performance of transition metal dichalcogenides (TMDs). While recent point defect reduction methods have led to considerable improvements in the optoelectronic properties of TMDs, there is a clear need for theoretical work to establish the lower limit of defect densities, as represented by thermal equilibrium. To that end, an ab initio and thermodynamic analysis of the equilibrium densities of intrinsic point defects in MoSe2 and WSe2 is presented.

Charge state-dependent symmetry breaking of atomic defects in transition metal dichalcogenides.

The functionality of atomic quantum emitters is intrinsically linked to their host lattice coordination. Structural distortions that spontaneously break the lattice symmetry strongly impact their optical emission properties and spin-photon interface. Here we report on the direct imaging of charge state-dependent symmetry breaking of two prototypical atomic quantum emitters in mono- and bilayer MoS by scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM).

Tetradic phosphor white light with variable CCT and superlative CRI through organolead halide perovskite nanocrystals.

In this work, the emission spectral range of halide perovskite nanocrystals is extended from violet to infrared, the widest emission range for halide perovskites to date. This range extension was made possible by a cost-effective solution-based synthesis process that only involves two halides [MAPb(Br I ) and MA = CHNH]. Furthermore, the correlated-color temperature (CCT) of white light is tuned by blending an appropriate fraction of the as-synthesized blue, green, yellow, and red emitting nanocrystals.