Three-dimensional conjugated poly(azomethine) networks were found to be promising candidates for applications in photocatalytic water splitting. Straightforward synthetic protocols lead to fully organic photocatalysts that showed enhanced long-time stability. Furthermore, the catalytic performance of these materials was correlated to the molecular composition and the optoelectronic properties of the samples.

CH 3 NH 3 PbX 3 (X = Cl, Br, I) perovskites were prepared by self-organization processes using different precursor solutions. The XRD analysis indicates the formation, at room temperature, of a tetragonal structure (space group I 4/mcm) for X = I, of a cubic structure (space group Pm3m) for X = Br and of centro-symmetric cubic structure (space group Pm3m) for X = Cl respectively. The structural analysis revealed the formation of CH3NH3Cl as secondary phase in the Cl-containing system. The morphological investigation revealed the formation of rhombo-hexagonal dodecahedra crystallite for X = I, Br whereas cube-like aggregates were observed for X = Cl. The thermogravimetric analysis performed in air did not reveal any loss until 250°C for X = I and 300°C for X = Br respectively whereas the differential thermal analysis (DTA) detected two endothermic thermal events (at 336°C and 409°C) for X = I and one only (379°C) for X = Br respectively. The infrared spectra (IR) of the powders conformed to the threefold symmetry of the methylammonium ion which rotates around the C-N axis. Optical absorption measurements indicated that the CH 3 NH 3 PbX 3 systems behave as direct-gap semiconductors with energy band gaps of 1.53eV for X = I, 2.20eV for X = Br and 3.00eV for X = Cl respectively at room temperature. The direct-gap semiconductivity for X = I and X = Br was confirmed by the photoluminescence emission measurements whereas the compound for X = Cl is inactive. I-containing powders were dissolved in an organic solvent (di-methyl-formamide, DMF). 100 -300 µL of the dispersion were dropped on glassy substrates on which thick films were obtained by spin-coating and thermal treatment at 120°C for ca. 5 minutes. The preparation of the layers was performed in air at room temperature.

Light-emitting electrochemical cells (LECs) are fabricated by gravure printing. The compromise between device performance and printing quality is correlated to the ink formulation and the printing process. It is shown that the rheological properties of the ink formulations of LECs can be tailored without changing the chemical composition of the material blend.

The synthesis and characterization of soluble azaiptycenes is reported. Optical and physical properties were studied and compared with those of the structurally consanguine azaacenes. Electrochemical experiments and quantum-chemical calculations revealed the electronic structure of the iptycene derivatives. Their crystallization behavior was examined. A highly fluorescent amorphous diazatetracene derivative was integrated into a simple organic light-emitting diode, showing enhanced performance compared with that of previously reported, structurally similar tetracenes.

We describe the modular synthesis of quinoxaline fluorophores exhibiting strong fluorescence over the whole visible spectrum. Based on their fluorescence quantum yield, frontier orbital energies and solidstate aggregation behavior, several compounds work well in fluorescent organic light emitting diodes (OLEDs) with luminances over 1000 cd m À2 at 8 V driving voltage.