Heteroleptic bis(tert-butylimido)bis(N,N'-diisopropylacetamidinato) compounds of molybdenum and tungsten are introduced as precursors for atomic layer deposition (ALD) of tungsten and molybdenum oxide thin films using ozone as the oxygen source. Both precursors have similar thermal properties, but exhibit different growth behavior. With the molybdenum precursor, high growth rates up to 2 Å/cycle at 300 °C and extremely uniform films are obtained, although the surface reactions are not completely saturative. The corresponding tungsten precursor enables saturative film growth with a lower growth rate of 0.45 Å/cycle at 300 °C. Highly pure films of both metal oxides are deposited and their phase as well as stoichiometry can be tuned by changing the deposition conditions. The WOx films crystallize as -WO3 at 300 °C and above while the films deposited at lower temperatures are amorphous. Molybdenum oxide can be deposited as either amorphous ( 250 °C), crystalline suboxide (275 °C), a mixture of suboxide and α-MoO3 (300 °C), or pure α-MoO3 films ( 325 °C). MoOx films are further characterized by synchrotron photoemission spectroscopy and temperaturedependent resistivity measurements. A suboxide MoOx film deposited at 275 °C is demonstrated to serve as an efficient hydrogen gas sensor at a low operating temperature of 120 °C.

Molybdenum disulfide (MoS2) is known for its versatile properties and hence promising for a wide range of applications. The fabrication of high-quality MoS2 either as homogeneous films or as two-dimensional...

This is the first report on a plasma enhanced spatial atomic layer deposition (APP-ALD) process at atmospheric pressure to grow conducting metallic Cu thin films from a carbene stabilized precursor.

Tetrazolium salts are exploited in various fields of research by virtue of their low reduction potentials. Increasingly, associated applications also attend to the photochemical and luminescence properties of these systems. Here, we investigate the photoinduced dynamics of phenyl-benzo[c]tetrazolo-cinnolinium chloride (PTC), one of the very few known fluorescent tetrazolium compounds, by using time-correlated single-photon counting, femtosecond fluorescence upconversion, and ultrafast transient absorption spectroscopy. PTC is generated photochemically by ultraviolet illumination of 2,3,5-triphenyl-tetrazolium chloride (TTC) in various alcohols. Time-resolved fluorescence measurements on PTC with different excitation wavelengths disclose biphasic solvation and vibrational relaxation dynamics. Depending on the solvent, the emission behavior of PTC is characterized by quantum yields on the order of several tens of percent and corresponding excited-state lifetimes of several hundreds of picoseconds. The radiative rate is basically constant for the studied alcohols, whereas the rate of the competing non-radiative process is sensitive to the solvent polarity. Hence, we discuss the possible involvement of intermediate radicals and further presumptive reaction pathways pursued after photoexcitation of PTC.

The unique structural and electronic properties of transition metal dichalcogenides (TMDs) and in particular tungsten disulphide (WS2) makes it interesting for a variety of applications such as electrocatalytic hydrogen evolution...

Thin films of iridium can be utilized in a wide range of applications and are particularly interesting for catalytic transformations. For the scalable deposition of functional Ir thin films, metal-organic chemical vapor deposition (MOCVD) is the method of choice, for which organometallic precursors that embody a high volatility and thermal stability need to be specifically tailored. Herein, we report the synthesis, analysis, and evaluation of new volatile Ir(I)-1,5-cyclooctadiene complexes bearing all-nitrogen coordinating guanidinate (DPDMG), amidinate (DPAMD) and formamidinate (DPfAMD) ligands. The amidinate-based Ir complex [Ir(COD)(DPAMD)] together with O2 was implemented in MOCVD experiments resulting in highly crystalline, dense, and conductive Ir films on a variety of substrate materials. The Ir deposits achieved an outstanding electrochemical performance with overpotentials in the range of 50 mV at –10 mA‧cm-2 for catalytic hydrogen evolution reaction (HER) in acidic solution. The ability to deposit Ir layers via MOCVD exhibiting promising functional properties is a significant step towards large scale applications.

Transition metal ferrites, such as CoFe2O4 (CFO) and NiFe2O4 (NFO), have gained increasing attention as potential materials for supercapacitors. Since chemical vapor deposition (CVD) offers advantages like interface quality to the underlying substrates and the possibility for coverage of 3D substrates, two CVD processes are reported for CFO and NFO. Growth rates amount to 150 to 200 nm h−1 and yield uniform, dense, and phase pure spinel ferrite films according to X‐ray diffraction (XRD), Raman spectroscopy, Rutherford backscattering spectrometry and nuclear reaction analysis (RBS/NRA) and scanning electron microscopy (SEM). Atom probe tomography (APT) and synchrotron X‐ray photoelectron spectroscopy (XPS) give insights into the vertical homogeneity and oxidation states in the CFO films. Cation disorder of CFO is analyzed for the first time from synchrotron‐based XPS. NFO is analyzed via lab‐based XPS. Depositions on conducting Ni and Ti substrates result in electrodes with pseudocapacitive behavior, as evidenced by cyclovoltammetry (CV) experiments. The interfacial capacitances of the electrodes are up to 185 µF cm−2.

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