Hot-exciton harvesting via through-space single-molecule based white-light emission and optical waveguides

Through-space donor–alkyl bridge–acceptor (D–σ–A) luminogens are developed as new organic single-molecule white light emitters (OSMWLEs) involving multiple higher lying singlet (S_n) and triplet (T_m) states (hot-excitons). Experimental and theoretical results confirm the origin of white light emission due to the co-existence of prompt fluorescence from locally excited states, thermally activated delayed fluorescence (TADF), and fast/slow dual phosphorescence color mixing simultaneously. Notably, the fast phosphorescence was observed due to trace amounts of isomeric impurities from commercial carbazole, while H-/J-aggregation resulted in slow phosphorescence. Crystal structure-packing-property analysis revealed that the alkyl chain length induced supramolecular self-assembly greatly influenced the solid-state optical properties. Remarkably, the 1D-microrod crystals of OSMWLEs demonstrated the first examples of triplet harvesting waveguides by self-guiding the generated phosphorescence through light propagation along their longitudinal axis. This work thus highlights an uncommon design strategy to achieve multi-functional OSMWLEs with in-depth mechanistic insights and optical waveguiding applications making them a potentially new class of white emissive materials.

Through-space donor–alkyl bridge–acceptor multifunctional organic single molecules that simultaneously displayed white light emission, thermally activated delayed fluorescence, room temperature dual phosphorescence and optical wave-guiding properties.     

Thermal characterization of titanium–titanium boride composites

Journal of Thermal Analysis and Calorimetry - Numerical simulation of mixed convection heat transfer in a lid-driven triangular cavity filled with power law nanofluid and with an opening was...     

Effect of Molybdenum (Mo) Addition on Phase Composition,Microstructure, and Mechanical Properties of Pre-Alloyed Ti6Al4V Using Spark Plasma Sintering Technique

The effect of molybdenum additions on the phases, microstructures, and mechanical properties of pre-alloyed Ti6Al4V was studied through the spark plasma sintering technique. Ti6Al4V-xMo (where x = 0, 2, 4, 6 wt.% of Mo) alloys were developed, and the sintered compacts were characterized in terms of their phase composition, microstructure, and mechanical properties. The results show that the equiaxed primary alpha and Widmänstatten (alpha + beta) microstructure in pre-alloyed Ti6Al4V is transformed into a duplex and globular model with the increasing content of Mo from 0 to 6%. The changing pattern of the microstructure of the sample strongly influences the properties of the material. The solid solution hardening element such as Mo enhances mechanical properties such as yield strength, ultimate tensile strength, ductility, and hardness compared with the pre-alloyed Ti6Al4V alloy.     

Catalysts based on hyperbranched pyridylphenylene polymers and palladium nanoparticles for the Suzuki—Miyaura cross-coupling reaction

Synthesis of catalysts based on hyperbranched pyridylphenylene polymer and palladium nanoparticles (РРР-Рd) is described. Catalytic activity in the Suzuki—Miyaura cross-coupling reaction is studied for the interaction of bromobenzene with phenylboronic acid. Optimal reaction conditions providing maximum conversion (100%) of the initial compounds are established.     

Inhomogeneous to homogeneous dynamical states through symmetry breaking dynamics

Nonlinear Dynamics - We explore the dynamical transitions facilitated by the symmetry breaking dynamical states in a directly coupled limit-cycle oscillators, when the oscillators are interacting...     

Mechanophotonics: Flexible Single‐Crystal Organic Waveguides and Circuits

We present the one‐dimensional optical‐waveguiding crystal dithieno[3,2‐a:2′,3′‐c]phenazine with a high aspect ratio, high mechanical flexibility, and selective self‐absorbance of the blue part of its fluorescence (FL). While macrocrystals exhibit elasticity, microcrystals deposited at a glass surface behave more like plastic crystals due to significant surface adherence, making them suitable for constructing photonic circuits via micromechanical operation with an atomic‐force‐microscopy cantilever tip. The flexible crystalline waveguides display optical‐path‐dependent FL signals at the output termini in both straight and bent configurations, making them appropriate for wavelength‐division multiplexing technologies. A reconfigurable 2×2‐directional coupler fabricated via micromanipulation by combining two arc‐shaped crystals splits the optical signal via evanescent coupling and delivers the signals at two output terminals with different splitting ratios. The presented mechanical micromanipulation technique could also be effectively extended to other flexible crystals.