Modulating the Supramolecular Assembly of α-Cyclodextrin and Anderson-type Polyoxometalate through Covalent Modifications.

A series of unprecedented supramolecular complexes of covalently modified Anderson-type polyoxometalates (POMs) and α-cyclodextrins (α-CDs) have been obtained and characterized in solid state by single-crystal X-ray diffraction, and in aqueous solution using various techniques including H DOSY NMR, 2D NOESY H NMR, isothermal titration calorimetry (ITC), and electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS). It has been demonstrated that the supramolecular assembly process could be modulated by different covalent modification modes of the Anderson POMs, giving rise to a new type of POM/α-CD complexes featuring organic-inorganic pseudo-rotaxane structures, which are in good contrast to those of POM/γ-CD complexes of poly-rotaxane structures. Moreover, it is delighted to find that these pseudo-rotaxanes of POM/α-CD complexes exhibit stable chirality in aqueous solution, which has not been accomplished in previously reported POM/CD assemblies.

Performance enhancement of deep-ultraviolet LEDs by using quaternary AlInGaN polarization-engineered multiple-symmetrical-stair quantum barriers without electron blocking layer.

In this paper, a structure design using quaternary AlInGaN as multiple-symmetrical-stair-shaped quantum barriers without an electron blocking layer is shown. The results show this design mitigates the droop effect to ∼0.1, and the internal quantum efficiency reaches about 93.

Prevalence and surveillance of tuberculosis in Yemen from 2006 to 2018.

Tuberculosis is a major public health issue in Yemen, a country located at the southwestern tip of the Arabian Peninsula, while the situation of tuberculosis had been further exacerbated since the war started in 2015. The objective of this study is to investigate the incidence of tuberculosis in Yemen before the outbreak of COVID-19, from 2006 to 2018. During the 13-year period, 92 482 patients were enrolled in the TB programme records from the 22 governorates.

Water-bath assisted convective assembly of aligned silver nanowire films for transparent electrodes.

Manipulating Ag nanowire (AgNW) assembly to tailor the opto-electrical properties and surface morphology could improve the performance of next-generation transparent conductive electrodes. In this paper, we demonstrated a water-bath assisted convective assembly process at the temporary water/alcohol interface for fabricating hierarchical aligned AgNW electrodes. The convection flow plays an important role during the assembly process.

Enhanced photovoltaic performance of organic/silicon nanowire hybrid solar cells by solution-evacuated method.

A method has been developed to fabricate organic-inorganic hybrid heterojunction solar cells based on n-type silicon nanowire (SiNW) and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) hybrid structures by evacuating the PEDOT:PSS solution with dip-dropping on the top of SiNWs before spin-coating (solution-evacuating). The coverage and contact interface between PEDOT:PSS and SiNW arrays can be dramatically enhanced by optimizing the solution-evacuated time. The maximum power conversion efficiency (PCE) reaches 9.

Performance enhancement of blue light-emitting diodes without an electron-blocking layer by using special designed p-type doped InGaN barriers.

In this study, the characteristics of the nitride-based blue light-emitting diode (LED) without an electron-blocking layer (EBL) are analyzed numerically. The emission spectra, carrier concentrations in the quantum wells (QWs), energy band diagrams, electrostatic fields, and internal quantum efficiency (IQE) are investigated. The simulation results indicate that the LED without an EBL has a better hole-injection efficiency and smaller electrostatic fields in its active region over the conventional LED with an AlGaN EBL.