Fluorescence of Intrinsic Milk Chromophores as a Novel Verification Method of UV-C Treatment of Milk.

The European Food Safety Authority (EFSA) has approved the use of a 1045 J/L UV-C dose as an adjunct to pasteurization to increase the shelf life and vitamin D3 content of milk. However, there are no verification methods analogous to the alkaline phosphatase test for pasteurized milk to ensure that the desired UV-C dose has been correctly applied. The aim is to develop a real-time in-line detector based on fluorescence spectroscopy.

All-Perovskite Multicomponent Nanocrystal Superlattices.

Nanocrystal superlattices (NC SLs) have long been sought as promising metamaterials, with nanoscale-engineered properties arising from collective and synergistic effects among the constituent building blocks. Lead halide perovskite (LHP) NCs come across as outstanding candidates for SL design, as they demonstrate collective light emission, known as superfluorescence, in single- and multicomponent SLs. Thus far, LHP NCs have only been assembled in single-component SLs or coassembled with dielectric NC building blocks acting solely as spacers between luminescent NCs.

Flexible, Free-Standing Polymer Membranes Sensitized by CsPbX3 Nanocrystals as Gain Media for Low Threshold, Multicolor Light Amplification.

Lead halide perovskite nanocrystals (NCs) are highly suitable active media for solution-processed lasers in the visible spectrum, owing to the wide tunability of their emission from blue to red via facile ion-exchange reactions. Their outstanding optical gain properties and the suppressed nonradiative recombination losses stem from their defect-tolerant nature. In this work, we demonstrate flexible waveguides combining the transparent, bioplastic, polymer cellulose acetate with green CsPbBr or red-emitting CsPb(Br,I) NCs in simple solution-processed architectures based on polymer-NC multilayers deposited on polymer micro-slabs.

Structural Diversity in Multicomponent Nanocrystal Superlattices Comprising Lead Halide Perovskite Nanocubes.

Nanocrystal (NC) self-assembly is a versatile platform for materials engineering at the mesoscale. The NC shape anisotropy leads to structures not observed with spherical NCs. This work presents a broad structural diversity in multicomponent, long-range ordered superlattices (SLs) comprising highly luminescent cubic CsPbBr NCs (and FAPbBr NCs) coassembled with the spherical, truncated cuboid, and disk-shaped NC building blocks.

Unraveling the Radiative Pathways of Hot Carriers upon Intense Photoexcitation of Lead Halide Perovskite Nanocrystals.

The slowdown of carrier cooling in lead halide perovskites (LHP) may allow the realization of efficient hot carrier solar cells. Much of the current effort focuses on the understanding of the mechanisms that retard the carrier relaxation, while proof-of-principle demonstrations of hot carrier harvesting have started to emerge. Less attention has been placed on the impact that the energy and momentum relaxation slowdown imparts on the spontaneous and stimulated light-emission process.

Robust Hydrophobic and Hydrophilic Polymer Fibers Sensitized by Inorganic and Hybrid Lead Halide Perovskite Nanocrystal Emitters.

Advances in the technology and processing of flexible optical materials have paved the way toward the integration of semiconductor emitters and polymers into functional light emitting fabrics. Lead halide perovskite nanocrystals appear as highly suitable optical sensitizers for such polymer fiber emitters due to their ease of fabrication, versatile solution-processing and highly efficient, tunable, and narrow emission across the visible spectrum. A beneficial byproduct of the nanocrystal incorporation into the polymer matrix is that it provides a facile and low-cost method to chemically and structurally stabilize the perovskite nanocrystals under ambient conditions.