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Spray coating, a simple and low‐cost technique for large‐scale film deposition, is employed to fabricate mesoporous titania films, which are electron‐transporting layers in all‐solid‐state dye‐sensitized solar cells (DSSCs). To optimize solar cell performance, presynthesized crystalline titania nanoparticles are introduced into the mesoporous titania films. The composite film morphology is examined with scanning electron microscopy, grazing incidence small‐angle X‐ray scattering, and nitrogen adsorption–desorption isotherms. The crystal phase and crystallite sizes are verified by X‐ray diffraction measurements. The photovoltaic performance of all‐solid‐state DSSCs is investigated. The findings reveal that an optimal active layer of the all‐solid‐state DSSC is obtained by including 50 wt% titania nanoparticles, showing a foam‐like morphology with an average pore size of 20 nm, featuring an anatase phase, and presenting a surface area of 225.2 m2 g−1. The optimized morphology obtained by adding 50 wt% presynthesized crystalline titania nanoparticles yields, correspondingly, the best solar cell efficiency of 2.7 ± 0.1%., Financial support by TUM.solar in the context of the Bavarian Collaborative Research Project “Solar Technologies Go Hybrid” (SolTech), by the GreenTech Initiative (Interface Science for Photovoltaics – ISPV) of the EuroTech Universities and by the Nanosystems Initiative Munich (NIM) is gratefully acknowledged. V.K. thanks the Bavarian State Ministry of Sciences, Research and Arts for funding this research work via project “Energy Valley Bavaria.” L.S., W.W., and Y.Y. acknowledge the China Scholarship Council (CSC).

A highly-ordered 3D covalent fullerene framework is presented with a structure based on octahedrally functionalized fullerene building blocks in which every fullerene is separated from the next by six functional groups and whose mesoporosity is controlled by cooperative self-assembly with a liquid-crystalline block copolymer. The new fullerene-framework material was obtained in the form of supported films by spin coating the synthesis solution directly on glass or silicon substrates, followed by a heat treatment. The fullerene building blocks coassemble with a liquid-crystalline block copolymer to produce a highly ordered covalent fullerene framework with orthorhombic Fmmm symmetry, accessible 7.5 nm pores, and high surface area, as revealed by gas adsorption, NMR spectroscopy, small-angle X-ray scattering (SAXS), and TEM. We also note that the 3D covalent fullerene framework exhibits a dielectric constant significantly lower than that of the nonporous precursor material.

Solution‐deposited‐converted perovskite solar cells are studied by converting PbI2 planar films into the phase pure, mixed‐halide perovskite (H3CNH3)PbI3‐x Clx . These solar cells exhibit very high photovoltaic performance and close to unity internal incident photon‐to‐electron conversion.

The energetic nitrogen-rich compounds 1,3-bis(1-methyltetrazol-5-yl)triaz-1-ene (4) and 1,3-bis(2-methyltetrazol-5-yl)triaz-1-ene (5) were synthesized by diazotation of 1-methyl-5-aminotetrazole (2) and 2-methyl-5-aminotetrazole (3), respectively, by using half an equivalent of sodium nitrite. The reaction of 4 and 5 with diluted ammonia solution yields ammonium bis(1-methyltetrazol-5-yl)triazenate (6) and ammonium bis(2-methyl-tetrazol-5-yl)triazenate (7). Treating of 4 and 5 with aqueous sodium hydroxide solution yields sodium bis(1-methyltetrazol-5-yl)triazenate (8) and sodium bis(2-methyltetrazol-5-yl)triazenate (9) almost quantitative. Compounds 8 and 9 were methylated using methyl iodide and dimethyl sulfate, respectively, originating bis(1-methyltetrazol-5-yl)-3-methyltriaz-1-ene (10) and bis(2-methyltetrazol-5-yl)-3-methyltriaz-1-ene (11). The products 4–11 were characterized by Raman, IR, multinuclear NMR and UV–Vis spectroscopy, mass spectrometry, elemental analysis and differential scanning calorimetry. The structures of the crystalline state of 4 · H2O, 5, 8 · MeOH, 10 and magnesium bis(2-methyltetrazol-5-yl)triazenate (12) were determined by low temperature single crystal X-ray diffraction. The heats of formation ΔfH∘ of 4–7, 10 and 11 were calculated using energies of combustion ΔcU∘ determined by bomb calorimetry, resulting in strongly endothermic values. With these data and by using calculated (4, 5, 10) as well as measured (6, 7, 11) crystal densities, several detonation parameter (heats of explosion, detonation pressure, detonation velocity, explosion temperature) were calculated by the explo 5 software. In addition, the specific impulse of different propellant mixtures of the most promising compound 6 with ammonium dinitramide (ADN) were computed. Furthermore the n-octanol/water partition coefficients of 4, 5, 6 and 7 were determined and the long-term stability of 6 was tested by thermal safety calorimetry. Lastly the sensitivities toward impact and friction as well as electrical discharge were determined by the BAM drophammer, friction tester and a small scale electrical discharge tester.

Incorporation of conjugated polymers into porous metal oxide networks is a challenging task, which is being pursued via many different approaches. We have developed the guided in situ polymerization of poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV) in porous titania films by means of surface functionalization. The controlled polymerization via the Gilch route was induced by an alkoxide base and by increasing the temperature. The selected and specially designed surface-functionalizing linker molecules mimic the monomer or its activated form, respectively. In this way, we drastically enhanced the amount of MEH-PPV incorporated into the porous titania phase compared to nonfunctionalized samples by a factor of 6. Additionally, photovoltaic measurements were performed. The devices show shunting or series resistance limitations, depending on the surface functionalization prior to in situ polymerization of MEH-PPV. We suggest that the reason for this behavior can be found in the orientation of the grown polymer chains with respect to the titania surface. Therefore, the geometry of the anchoring via the linker molecules is relevant for exploiting the full electronic potential of the conjugated polymer in the resulting hybrid composite. This observation will help to design future synthesis methods for new hybrid materials from conjugated polymers and n-type semiconductors to take full advantage of favorable electronic interactions between the two phases.

Although macroporous titania scaffolds are used for many different applications, not much is known about the importance of the synthesis strategy on the resulting materials' properties. We present a comparative study on the influence of different colloidal titania precursors for direct co-deposition with poly(methyl methacrylate) (PMMA) beads on the properties of the resulting macroporous scaffolds after calcination. The colloidal titania precursors for the film assembly differ in their size and initial crystallinity, ranging from amorphous sol–gel clusters to already crystalline pre-formed particles of 4 nm, 6 nm and 20 nm in size, as well as a combination of sol–gel and nanoparticle precursors in the so-called ‘Brick and Mortar’ approach. The type of the precursor greatly influences the morphology, texture and the specific crystallinity parameters of the macroporous titania scaffolds after calcination such as the size of the crystalline domains, packing density of the crystallites in the macroporous walls and interconnectivity between the crystals. Moreover, the texture and the crystallinity of the films can be tuned by post-synthesis processing of the films such as calcination at different temperatures, which can be also preceded by a hydrothermal treatment. The ability to adjust the porosity, the total surface area and the crystallinity parameters of the crystalline macroporous films by selecting suitable precursors and by applying different post-synthetic treatments provides useful tools to optimize the film properties for different applications.