Lead
halide perovskites (LHPs) are emerging as promising materials
for light-emitting device applications because of the tunability of
the band gap, narrow emission, solution processability, and flexibility.
Typically, LHP nanocrystals (NCs) with surface ligands show high photoluminescence
quantum yields because of charge-carrier confinement with higher exciton
binding energy (E
b). However, the conventionally
used oleylamine (OAm) ligands result in the low electrical conductivity
and stability of perovskite NCs (PNCs) because of a long carbon chain
without conjugation bonds and weak interaction with the surface of
NCs. Here, we report the effect of bulkiness and chain length of ligand
materials on the properties and stability of CsPbBr3 PNCs
by replacing OAm with other suitable ligands. The effect of the bulkiness
of quaternary ammonium bromide (QAB) ligands was systemically studied.
The less bulky QAB ligands surrounded the surface of NCs effectively,
and brought better surface passivation and less aggregation compared
to bulky QAB ligands, and finally the optical property and stability
of CsPbBr3 PNCs were enhanced. Furthermore, the electrical
property of CsPbBr3 PNCs was optimized by tuning the long-chain
length of QAB ligands for balanced charge-carrier transport. Finally,
we achieved highly efficient green emissive CsPbBr3 PNC
light-emitting diodes (LEDs) by using PNCs with optimized didecyldimethyl
ammonium bromide ligands with a current efficiency of 31.7 cd A–1 and external quantum efficiency of 9.7%, which were
enhanced 16-fold compared to those of CsPbBr3 LEDs using
PNCs with conventional OAm ligands.
It is well known that embryos cultured in a group can create a microenvironment through secretion of autocrine and paracrine factors that can support and improve the embryos' development when compared to the embryos cultured individually. In this study, we used a co-culture system for paracrine communication between different kinds of embryos. The results showed that co-culture of porcine parthenogenetic (PA) embryos significantly improved the in vitro development of cloned (nuclear transfer, NT) embryos. To reveal the possible mechanism of communication between the two groups, we isolated exosomes/microvesicles (EXs/MVs) from the PA embryos conditioned medium (PA-CM) through differential centrifugation and identified them through transmission electron microscope and immunoflourescence against exosomal/membrane marker CD9. Furthermore, these EXs/MVs were found to contain mRNA of pluripotency genes (Oct4, Sox2, Klf4, c-Myc, and Nanog), and the PKH67-labeled EXs/MVs could be internalized by the NT embryos. The current study demonstrates that cloned embryos' developmental competence can be improved through co-culturing with PA embryos and revealed, for the first time, that in vitro-produced embryos can secrete EXs/MVs as a possible communication tool within their microenvironment. Moreover, it provides a new paradigm for embryo-to-embryo communication in vitro.
Colloidal quantum dots can control the bandgap by controlling the particle size, and are capable of solution processing, which is cost competitive, and has a narrow half width of the emission wavelength.Using these characteristics, it is possible to utilize various kinds of LED, solar cell, and bio imaging.Among them, indium phosphide (InP) quantum dots have a bandgap capable of emitting light in the near-infrared region from the visible light region, and are less toxic to humans and the environment than cadmium-based quantum dots, and are attracting attention as next generation light emitting materials.However, the limited choice and high cost of P precursors have a negative impact on their practical applicability. In this work, I report the large-scale synthesis of highly luminescent InP@ZnS QDs from an elemental P precursor (P4), which was simply synthesized via the sublimation of red P powder. The size of the InP QDs was controlled by varying the reaction parameters such as the reaction time and temperature, and the type of In precursors. This way, the photoluminescence properties of the synthesized InP@ZnS QDs could be easily tuned across the entire visible range, while their quantum yield could be increased up to 60% via the optimization of reaction conditions. Furthermore, possible reaction pathways for the formation of InP QDs using the P4 precursor have been investigated with nuclear magnetic resonance spectroscopy and it was demonstrated that the direct reaction of P4 precursor with In precursor produces InP structures without the formation of intermediate species. The large-scale production of InP@ZnS QDs was demonstrated by yielding more than 6 g of QDs per onebatch reaction.In the case of InP using different precursor P except the Tris(Trimethylsilyl) phosphine ((TMS)3P) there has been a problem that the size distribution is poor. Two kinds of P precursors with different reactivities were used to separate the nucleation and growth processes and to induce growth along the Lamer mechanism to produce uniform particles. For this, (TMS)3P and DEAP were used as fast reacting P precursors, and P4 was used as a slow reacting P precursor. Through this, the possibility of uniform particle formation was observed. I strongly believe that the newly developed approach bears the potential to be widely used for manufacturing inexpensive high-quality QD emitters.
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We demonstrate that oviduct cells at the estrus stage highly expressed MAPK1/3, SMAD2/3, and BMP15. Furthermore, canine oviduct cells from the estrus stage enhance the culture environment for canine oocyte maturation.
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