Original Core–Shell Structure of Cubic CsPbBr₃@Amorphous CsPbBr_<i>x</i> Perovskite Quantum Dots with a High Blue Photoluminescence Quantum Yield of over 80%

All-inorganic perovskite cesium lead halide quantum dots (QDs) have been widely investigated as promising materials for optoelectronic application because of their outstanding photoluminescence (PL) properties and benefits from quantum effects. Although QDs with full-spectra visible emission have been synthesized for years, the PL quantum yield (PLQY) of pure blue-emitting QDs still stays at a low level, in contrast to their green- or red-emitting counterparts. Herein, we obtained core–shell structured cubic CsPbBr₃@amorphous CsPbBr_<i>x</i> (A-CsPbBr_<i>x</i>) perovskite QDs via a facile hot injection method and centrifugation process. The core–shell structure QDs showed a record blue emission PLQY of 84%, which is much higher than that of blue-emitting cubic CsPbBr₃ QDs and CsPbBr_<i>x</i>Cl_3–<i>x</i> QDs. Furthermore, a blue-emitting QDs-assisted LED with bright pure blue emission was prepared and illustrated the core–shell QDs’ promising prospect in optoelectrical application

Programming Saposin-Mediated Compensatory Metabolic Sinks for Enhanced Ubiquinone Production

Microbial synthesis of ubiquinone by fermentation processes has been emerging in recent years. However, as ubiquinone is a primary metabolite that is tightly regulated by the host central metabolism, tweaking the individual pathway components could only result in a marginal improvement on the ubiquinone production. Given that ubiquinone is stored in the lipid bilayer, we hypothesized that introducing additional metabolic sink for storing ubiquinone might improve the CoQ₁₀ production. As human lipid binding/transfer protein saposin B (hSapB) was reported to extract ubiquinone from the lipid bilayer and form the water-soluble complex, hSapB was chosen to build a compensatory metabolic sink for the ubiquinone storage. As a proof-of-concept, hSapB-mediated metabolic sink systems were devised and systematically investigated in the model organism of <i>Escherichia coli</i>. The hSapB-mediated periplasmic sink resulted in more than 200% improvement of CoQ₈ over the wild type strain. Further investigation revealed that hSapB-mediated sink systems could also improve the CoQ₁₀ production in a CoQ₁₀-hyperproducing <i>E. coli</i> strain obtained by a modular pathway rewiring approach. As the design principles and the engineering strategies reported here are generalizable to other microbes, compensatory sink systems will be a method of significant interest to the synthetic biology community

High-Voltage-Efficiency Inorganic Perovskite Solar Cells in a Wide Solution-Processing Window

Inorganic halide perovskites exhibit significant photovoltaic performance due to their structural stability and high open-circuit voltage (<i>V</i>_oc). Herein, a general strategy of solution engineering has been implemented to enable a wide solution-processing window for high <i>V</i>_oc (∼1.3 V) and power conversion efficiency (PCE, ∼12.5%). We introduce a nontoxic solvent of dimethyl sulfoxide (DMSO) and an assisted heating process in the fabrication of CsPbI₂Br (CPI2) to control the improved crystallization. A wide solution-processing window including a wide range of solvent components and solute concentrations has been realized. The CPI2-based inorganic perovskite solar cells (IPSCs) exhibit a high PCE up to 12.52%. More importantly, these devices demonstrate a remarkable <i>V</i>_oc of 1.315 V. The performance has possessed such a region with high <i>V</i>_oc and PCE in all Cs-based IPSCs, unveiling wide solution-processing windows with enhanced solution processability facilitating potential industrial application especially for tandem solar cells