Large-grained CuInSe 2 absorber layers are synthesized using a non-vacuum process based on nanoparticle ink precursors and selenization by rapid thermal processing (RTP). The use of hydroxide-based particles in organic solvents allows for the conversion with elemental selenium without the need to employ explosive and/or toxic H 2 or H 2 Se gasses. Lateral grain sizes up to 4 μm are obtained through a novel RTP route, overcoming the inherently high layer porosity for previous nanoparticle processes. Morphological and elemental characterization at interrupted selenization steps suggests that liquid selenium can play a beneficial role in promoting layer densification and grain growth. Long carrier collection lengths in CuInSe 2 enable notable conversion efficiencies, despite the low minority carrier lifetimes of below 1 ns. Record efficiencies up to 8.73% highlight the potential of low-cost, non-vacuum deposition of chalcopyrite absorber layers with safe and simple precursors and processing routes.

The adsorption of diastereoisomers of tartaric acid, namely, meso (R,S)-tartaric acid, (R,R)-tartaric acid, and the racemic mixture of (R,R) and (S,S) tartaric acid on the (111) surface of a copper single crystal has been studied by means of reflection-absorption IR Spectroscopy, X-ray photoelectron spectroscopy, low-energy electron diffraction, and thermal desorption spectroscopy. Two distinct adsorption modes are identified for all three adsorbate systems. All molecules undergo an identical thermally induced autocatalytic decomposition reaction above 510 K. The pure enantiomers show 2D chiral long-range ordered structures of opposite handedness.

Surface-adsorbed macrocycles exhibit a number of interesting physical and chemical properties; many of them are determined by their transition-metal centers. The hierarchical exchange of the central metal atom in such surface-adsorbed complexes is demonstrated, specifically in the porphyrin-like macrocycle pyrphyrin adsorbed on Cu(111). Using scanning tunneling microscopy and X-ray photoelectron spectroscopy, we show that Cu as central metal atom is easily exchanged with Ni or Fe atoms supplied in trace amounts to the surface. Atom exchange of Ni centers with Fe atoms also occurs, with moderate yield. These results allow ranking the stability of the surface-adsorbed Cu, Ni, and Fe complexes. The fact that the atom exchange occurs at 423 K shows that surface-adsorbed macrocycles can be surprisingly easily transformed.

Chemical reactions occurring on surfaces may provide an alternate route to materials beyond traditional methods, e.g. large polymers or compounds that would react further in ambient conditions or lack solubility. Many on-surface reactions yield atomic hydrogen which then desorbs swiftly from noble metals of group 11 (Cu, Ag, Au). Using a porphyrin-related macrocycle, so-called pyrphyrin, also bearing two cyano groups at the periphery, we show that dehydrogenation of the center of the macrocycle leads to selective formation of hydrogen cyanide, created from the rim-cyano groups and the hydrogen of the center imine (=NH). Formally, the surface-remaining reaction product is a dicarbene, bearing two divalent carbon atoms. It reacts readily with Fe atoms at room temperature, unlike its pyrphyrin precursor, which requires annealing for metalation with Fe. The hydrogen cyanide abstraction becomes suppressed when pyrphyrin is metalated with iron atoms, because the absence of the two hydrogen atoms does not allow the tautomerization.

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