The low artemisinin content in Artemisia has caused this compound to be expensive among medicines. Several attempts have been made to increase its production by altering the expression of different genes. However, no approach has been cost-effective. In this study, the expression levels of SQS and DBR2 genes were quantified by qRT-PCR, and artemisinin content was measured by HPLC in Artemisia annua cell suspension culture under nano cobalt particles elicitation. For this purpose, nano cobalt particles were used in 0.25, 2.5, and 5 mg L -1 concentrations and samples were collected after 8, 24, 48, and 72 h. The highest artemisinin content was observed 24 h after 5 mg L -1 nano cobalt treatment. In this case, artemisinin production was 2.25-fold (113.35 mg g -1 dw) higher than that of the control. Simultaneously, the expression levels of SQS and DBR2 genes decreased. It appears that the decrease in the expression of SQS and DBR2 genes caused the artemisinin content to increase by high concentrations of the nano cobalt particles.

In recent work, the boron hydride anti-B18H22 was announced in the literature as a new laser dye, and, along with several of its derivatives, its solutions are capable of delivering blue luminescence with quantum yields of unity. However, as a dopant in solid polymer films, its luminescent efficiencies reduce dramatically. Clarification of underlying detrimental effects is crucial for any application and, thus, this contribution makes the initial steps in the use of these inorganic compounds in electrooptical devices based on organic polymer thin films. The photoluminescence behavior of the highly luminescent boron hydrides, anti-B18H22 and 3,3′,4,4′-Et4-anti-B18H18, were therefore investigated. The quantum yields of luminescence and photostabilities of both compounds were studied in different solvents and as polymer-solvent blends. The photophysical properties of both boranes are evaluated and discussed in terms of their solvent-solute interactions using photoluminescence (PL) and NMR spectroscopies. The UV degradability of prepared thin films was studied by fluorimetric measurement. The effect of the surrounding atmosphere, dopant concentration and the molecular structure were assessed.

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Poly(9,9-dioctyfluorene-alt-benzothiadiazole), F8BT, thin films were successfully deposited using spin coating and drop-casting methods on glass and silicon substrates. Films with thicknesses varying from tens to hundreds of nanometers were obtained as a result of variation in the deposition conditions, such as concentration or coating methods. The trends in manifestations of 0-0 and 0-1 vibronic transitions in UV-VIS absorption and photoluminescence (PL) spectra correlate with the thickness of the thin films. A threshold in the intensity ratio of the two transitions was observed at the thin film thickness about 250 nm. The observed spectral features are interpreted in terms of the competitive effects of J-and H-aggregation of the macromolecular chains.

Electronic devices based on polymer thin films have experienced a tremendous increase in their efficiency in the last two decades. One of the critical factors that affects the efficiency of polymer solar cells or light emitting devices is the presence of structural defects that controls non-radiative recombination. The purpose of this report is to demonstrate a non-trivial thickness dependence of optoelectronic properties and structure (dis)order in thin conductive poly(9,9-dioctyfluorene-alt-benzothiadiazole), F8BT, polymer films. The UV-Vis absorption spectra exhibited blue shift and peak broadening; significant changes in 0–0 and 0–1 radiative transition intensity was found in photoluminescence emission spectra. The density of state (DOS) was directly mapped by energy resolved-electrochemical impedance spectroscopy (ER-EIS). Satellite states 0.5 eV below the lowest unoccupied molecular orbital (LUMO) band were revealed for the thinner polymer films. Moreover, the decreasing of the deep states density in the band gap manifested an increment in the material structural ordering with increasing thickness. Changes in the ratio between crystalline phases with face-on and edge-on orientation of F8BT chains were identified in the films by grazing-incidence wide angle X-ray scattering technique. A thickness threshold in all investigated aspects of the films at a thickness of about 100 nm was observed that can be attributed to the development of J-H aggregation in the film structure and mutual interplay between these two modes. Although a specific structure–property relationship thickness threshold value may be expected for thin films prepared from various polymers, solvents and under different process conditions, the value of about 100 nm can be generally considered as the characteristic length scale of this phenomenon.