Zinc oxide is a very promising material for short‐wavelength light‐emitting devices due to its large band gap and high exciton binding energy. Although great progress has been made in recent years, p‐type doping and control over native defects introduced during or after material growth are still significant problems that hinder the development of efficient ZnO based optoelectronic devices. Here we demonstrate a versatile method for the growth or p‐type or n‐type ZnO nanorods from the same growth solution at temperature as low as 90 °C, where the conductivity type is controlled by the preparation of the seed layer for nanorod growth. The differences in the conductivity type can be attributed to dependency of native defect concentrations and hydrogen incorporation on the seed layer preparation method. Room temperature electroluminescence has been demonstrated from homojunction and heterojunction light emitting diodes containing p‐ZnO nanorods.

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An earlier optimisation approach proposed by Luo et al. [Luo, J., Lin, J., Dean, T. A., 2006. A Study on the Determination of Mechanical Properties of a power-law Material by Its Indentation Force-Depth Curve. Philosophical Magazine, 86(19), 2881-2905], which is based on the assumption that the instrumented indentation force-depth response of an elastic-plastic material is a linear combination of the corresponding elastic and elastic-perfect plastic materials, is extended in this work to extract mechanical properties of a power-law material from two given experimental indentation P-h curves for conical indenters of half included angles of 60°and 70.3°. It was found that the non-uniqueness problem encountered in the single P-h curve optimisation approach is effectively removed by the two P-h curves optimisation. The appropriateness of the use of second half included angle of 60°is discussed. For the five representative materials Al, Ti, Fe, Ni and steel, it was found that the maximum relative prediction errors for E, r y and n are 2%, 10.4% and 11.3%, respectively. The prediction accuracy of mechanical properties E, r y and n is generally better than other methods reported in the literature.

Dielectric films are the foundation of power electronic equipment for energy storage in capacitors. However, typical dielectric films exhibit undesirable energy storage density and thermal stability, limiting its further application in the advanced field. For both pure polymers and composites‐based dielectrics, the macromolecular matrix greatly determines the performances. This paper summarizes the research progress of all‐organic polymer materials for the dielectric application from the perspective of molecular structure design. Systematic comparisons on properties, including dielectric constant and dielectric loss, glass transition temperature, and energy density are given, expecting to inspire researchers to devote further efforts in this area. An outlook for the future of all‐polymer dielectrics is also presented.