Conformational NMR Study of Bistriazolyl Anion Receptors.

Conformational features of pyridine- and pyrimidine-based bistriazolyl anion receptors dissolved in acetonitrile-d3 were assessed by multidimensional, heteronuclear NMR spectroscopy. NOESY correlation signals suggested preorganization of both host molecules in solution in the absence of anions. In addition, only a single set of signals was observed in the 1H NMR spectra, which suggested a symmetrical conformation of anion receptors or their conformational exchange that is fast on the NMR time-scale. Furthermore, the predominant conformations of the pyridine- and pyrimidine-based anion receptors are preserved upon addition of chloride, bromide, and acetate anions. Chemical shift changes observed upon addition of anions showed that the NH (thio)urea and triazole protons are involved in anion-receptor interactions through hydrogen bonding.

Anion binding and transport properties of cyclic 2,6-bis(1,2,3-triazol-1-yl)pyridines.

A series of cyclic 2,6-bis-(1,2,3-triazolyl)-pyridine anion receptors with thiourea functionalities were synthesized by click reaction of 2,6-diazidopyridine with protected propargylamine followed by condensation of a bisthiocyanate derivative with a series of diamines. Their chloride binding affinities as well as their transport properties in POPC bilayers were examined. These receptors were found to function as anion carriers, which can mediate both Cl(-)/NO3(-) antiport and H(+)/Cl(-) symport, and the transport activity of these hosts were dominated by their lipophilicity.

Outdoor Measurement and Modeling of Perovskite Module Temperatures.

Photovoltaic cells and modules are exposed to partially rapid changing environmental parameters that influence the device temperature. The evolution of the device temperature of a perovskite module of 225 cm2 area is presented during a period of 25 days under central European conditions. The temperature of the glass-glass packaged perovskite solar module is directly measured at the back contact by a thermocouple. The device is exposed to ambient temperatures from 3 to 34 °C up to solar irradiation levels exceeding 1300 W m-2. The highest recorded module temperature is 61 °C under constant high irradiation levels. Under strong fluctuations of the global solar irradiance, temperature gradients of more than 3 K min-1 with total changes of more than 20 K are measured. Based on the experimental data, a dynamic iterative model is developed for the module temperature evolution in dependence on ambient temperature and solar irradiation. Furthermore, specific thermal device properties that enable an extrapolation of the module response beyond the measured parameter space can be determined. With this set of parameters, it can be predicted that the temperature of the perovskite layer in thin-film photovoltaic devices is exceeding 70 °C under realistic outdoor conditions. Additionally, perovskite module temperatures can be calculated in final applications.