A Stepwise Reaction Achieves Ultrasmall AgZnSnS Nanocrystals.

Pirquitasite AgZnSnS (AZTS) nanocrystals (NCs) are emergent, lead-free emissive materials in the coinage chalcogenide family with applications in optoelectronic technologies. Like many multinary nanomaterials, their phase-pure synthesis is complicated by the generation of impurities, e.g.

The smallest PbS nanocrystals pervasively show decreased brightness, linked to surface-mediated decay on the average particle.

PbS semiconductor nanocrystals (NCs) have been heavily explored for infrared optoelectronics but can exhibit visible-wavelength quantum-confined optical gaps when sufficiently small (⌀ = 1.8-2.7 nm).

Photonic enhancement in photoluminescent metal halide perovskite-photonic crystal bead hybrids.

We report two photonic crystal-perovskite nanocrystal microbead hybrids with photoluminescence matching that of the parent nanocrystals but with increased photoluminescence quantum yields. Time-resolved photoluminescence spectroscopy quantifies the radiative enhancement afforded by the photonic environment of the microbeads. The reported hybrids also demonstrate markedly better resistance to degradation in water over 30 days of immersion.

Photon Upconversion in a Vapor Deposited 2D Inorganic-Organic Semiconductor Heterostructure.

Energy transfer processes may be engineered in van der Waals heterostructures by taking advantage of the atomically abrupt, Å-scale, and topologically tailorable interfaces within them. Here, we prepare heterostructures comprised of 2D WSe monolayers interfaced with dibenzotetraphenylperiflanthene (DBP)-doped rubrene, an organic semiconductor capable of triplet fusion. We fabricate these heterostructures entirely through vapor deposition methods.

Sequential Carrier Transfer Can Accelerate Triplet Energy Transfer from Functionalized CdSe Nanocrystals.

Nanocrystal (NC)-sensitized triplet-fusion upconversion is a rising strategy to convert long-wavelength, incoherent light into higher-energy output photons. Here, we chart the photophysics of tailor-functionalized CdSe NCs to understand energy transfer to surface-anchored transmitter ligands, which can proceed via correlated exciton transfer or sequential carrier hops. Varying NC size, we observe a pronounced acceleration of energy transfer (from = 0.

Synthesis and optoelectronic properties of radical conjugated polyfluorenes.

A novel redox-active fluorene monomer is synthesized and copolymerized with 9,9-dioctylfluorene and benzo[][1,2,5]thiadiazole Suzuki cross-coupling to produce alternating and tertiary copolymers. Electrochemical and chemical reduction of the copolymers generates organic polymeric radical anions. Electrochemical, spectroscopic, and photophysical characterization grant insight into the structure-property relationship for open-shell conjugated polymers.

Ultra-small PbS nanocrystals as sensitizers for red-to-blue triplet-fusion upconversion.

Photon upconversion is a strategy to generate high-energy excitations from low-energy photon input, enabling advanced architectures for imaging and photochemistry. Here, we show that ultra-small PbS nanocrystals can sensitize red-to-blue triplet-fusion upconversion with a large anti-Stokes shift (Δ = 1.04 eV), and achieve max-efficiency upconversion at near-solar fluences ( = 220 mW cm) despite endothermic triplet sensitization.

Triplet-Fusion Upconversion Using a Rigid Tetracene Homodimer.

We demonstrate that a structurally rigid, weakly coupled molecular dimer can replace traditional monomeric annihilators for triplet fusion upconversion (TUC) in solution by observing emitted photons (λ = 540 nm) from a norbornyl-bridged tetracene homodimer following excitation of a triplet sensitizer at λ = 730 nm. Intriguingly, steady-state spectroscopy, kinetic simulations, and Stern-Volmer quenching experiments show that the dimer exhibits qualitatively different photophysics than its parent monomer: it is less effective at diffusion-mediated triplet exciton transfer, but it fuses extracted triplets more efficiently. Our results support the development of composite triplet-fusion platforms that go beyond diffusion-mediated triplet extraction, ultimately circumventing the concentration dependence of solution-phase TUC.

The Hepatitis Delta Virus accumulation requires paraspeckle components and affects NEAT1 level and PSP1 localization.

The Hepatitis Delta Virus (HDV) relies mainly on host proteins for its replication. We previously identified that PSF and p54nrb associate with the HDV RNA genome during viral replication. Together with PSP1, these proteins are part of paraspeckles, which are subnuclear bodies nucleated by the long non-coding RNA NEAT1.

Orthogonally Processable Carbazole-Based Polymer Thin Films by Nitroxide-Mediated Polymerization.

Cross-linking of hole-transporting polymer thin films in organic light emitting diodes (OLEDs) has been shown to increase device efficacy when subsequent layers are deposited from solution. This improvement, due to resistance of the films to dissolution, could also be achieved by covalently grafting the polymer film to the substrate. Using nitroxide-mediated polymerization (NMP), we synthesized a novel poly(9-(4-vinylbenzyl)-9H-carbazole) (poly(VBK)) copolymer which can be cross-linked and also developed two simple methods for the grafting-to or grafting-from, also known as surface-initiated polymerization, of poly(VBK) to indium tin oxide (ITO) substrates.