Organic Kainate Single Crystals for Second-Harmonic and Broadband THz Generation.

Organic crystals with unique nonlinear optical properties have been attracting attention owing to their capability to outperform their conventional nonorganic counterparts. Since nonlinear material responses are linked to a crystal's internal microscopic structure, molecular engineering of maximally unharmonic quantum potentials can boost macromolecular susceptibilities. Here, large-scale kainic acid (kainate) single crystals were synthesized, and their linear and nonlinear optical properties were studied in a broad spectral range, spanning the visible to THz spectral regions.

Multicolor Phenylenediamine Carbon Dots for Metal-Ion Detection with Picomolar Sensitivity.

Carbon dots keep attracting attention in multidisciplinary fields, motivating the development of new compounds. Phenylenediamine CH(NH) dots are known to exhibit colorful emission, which depends on size, composition, and the functional surface groups, forming those structures. While quite a few fabrication protocols have been developed, the quantum yield of phenylenediamine dots still does not exceed 50% owing to undesired fragment formation during carbonization.

Novel Ultra Localized and Dense Nitrogen Delta-Doping in Diamond for Advanced Quantum Sensing.

We introduce and demonstrate a new approach for nitrogen-vacancy (NV) patterning in diamond, achieving a deterministic, nanometer-thin, and dense delta-doped layer of negatively charged NV centers in diamond. We employed a pure nitridation stage using microwave plasma and a subsequent diamond overgrowth. We present the highest reported nitrogen concentration in a delta-doped layer (1.