Single and double cyclophenylene–ethynylenes (CPEs) with axial and helical chirality have been synthesized by the Sonogashira cross‐coupling of di‐ and tetraethynyl biphenyls with a U‐shaped prearomatic diiodoparaphenylene followed by reductive aromatization. X‐ray crystallographic analyses and DFT calculations revealed that the CPEs possess highly twisted bent structures. Bend angles on the edge of the paraphenylene units were close to the value of [5]cycloparaphenylene (CPP)—the smallest CPP to date. The double and single CPEs possessed stable chirality despite flexible biphenyl structures because of the high strain in the diethynyl–paraphenylene moiety. In both the single and double CPEs, orbital interactions along the biphenyl axis were observed by DFT calculations in LUMO and LUMO+2 of the single CPE and LUMO+1 of the double CPE, which likely cause lowering of these orbital energies. Concerning chiroptical properties: boosting of the gabs value was observed in the biphenyl‐based double CPE, as well as the binaphthyl‐based single CPE, compared to the biphenyl‐based single CPE.

Photonic crystals are periodic dielectric structural materials that have photonic band gaps, and are divided into on-dimensional, two-dimensional, and three-dimensional structures based on their spatial distributions. One-dimensional photonic crystals have already found real-world applications. Three-dimensional photonic crystals are still in the experimental phase in laboratories. Due to their superior characteristics, photonic crystal materials are sure to be widely developed and applied in the future. This paper briefly introduces the principle of photonic crystals, facts about their theoretical research, production and preparation of materials, as well as their related applications. Photonic crystal materials have a lot of potential, and could be one of the most significant materials of this century. Since the concept was proposed in the late 80’s of the previous century, the research and application of photonic crystals has advanced significantly. Currently, photonic crystals are already used in fiber optics as well as semiconductor lasers. This paper introduces the structures of various types of photonic crystals, including photonic crystals with semiconductor and fiber optic material bases, and describes some of the special optoelectronic characteristics and possible applications of photonic crystals. Photonic crystals can be used in the production of many new types of optoelectronic devices. Most significantly, they can dramatically reduce the size of components and result in dense integration. Photonic crystals are expected to have a revolutionary impact on the development of optoelectronic technologies.

This experiment applied the vapor transport method and the AZO catalyst, and successfully grew ZnO nanowires on silicon substrate. The results showed that the factors such as the position of growth substrate, temperature, temperature rising rate, growth time, gas flow volume, and the proportion of ZnO and carbon composition powder, could decide the quality and characteristics of ZnO nanowire. Optimal conditions for ZnO nanowire growth were: carbon and ZnO powders mixed at a 1:1 weight ratio to serve as the material for growing nanowires, located at a distance of 10 cm from the silicon substrate which already had AZO thin film deposed on it; the growth temperature was set at 1100°C for a continuous duration of 70 minutes; the flow volumes of the nitrogen and oxygen gases within the furnace pipe were 70 and 60 sccm, and the furnace pipe temperature rising rate was 20°C/min. In addition, it was observed by FE-SEM that when the substrate was away from the source material by 10 cm, there was nanowire with the radius of 0.11μm and length of 9.3μm. By X-ray we found the characteristic wave summit of ZnO with lattice parameter a = 0.3249 nm and c = 0.5206 nm, was in fine single crystal structure and the directions were all in (002).In field emission measurements, when the current densities was 0.1μA/cm2, the lower initial electric fields corresponding to it was 0.11 V/μm and had the best field enhancement factor with a value of 1782.

The vapor transport method was used to grow ZnO nanowires on ZnO:Al (AZO) deposited silicon substrate. The optimal characteristic of ZnO nanowires was grown at 1100°C for 70 min, together with a ZnO/graphite weight ratio of 1:1 and N2/O2 flow ratio of 7:6. ZnO nanowires had a single crystalline structure and grew with a prefer direction in the (002) plane. Photoluminescence measurement showed that UV and visible green emission bands were observed. The turn-on electric field of ZnO nanowires was 0.11 V/μm and the maximum field emission current density was 1.8 mA/cm2. A high field enhancement factor of 1782 was evaluated.

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