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Vacuum‐based deposition of optoelectronic thin films has a long‐standing history. However, in the field of perovskite‐based photovoltaics, these techniques are still not as advanced as their solution‐based counterparts. Although high‐efficiency vacuum‐based perovskite solar cells reaching power conversion efficiencies (PCEs) above 20% are reported, the number of studies on the underlying physical and chemical mechanism of the co‐evaporation of lead iodide and methylammonium iodide is low. In this study, the impact of one of the most crucial process parameters in vacuum processes — the substrate material — is studied. It is shown that not only the morphology of the co‐evaporated perovskite thin films is significantly influenced by the surface polarity of the substrate material, but also the incorporation of the organic compound into the perovskite framework. Based on these studies, a selection guide for suitable substrate materials for efficient co‐evaporated perovskite thin films is derived. This selection guide points out that the organic vacuum‐processable hole transport material 2,2″,7,7″‐tetra(N,N‐di‐p‐tolyl)amino‐9,9‐spirobifluorene is an ideal candidate for the fabrication of efficient all‐evaporated perovskite solar cells, demonstrating PCEs above 19%. Furthermore, building on the insights into the formation of the perovskite thin films on different substrate materials, a basic crystallization model for co‐evaporated perovskite thin films is suggested.

In the urge of designing noble metal‐free and sustainable electrocatalysts for oxygen evolution reaction (OER), herein, a mineral Digenite Cu₉S₅ has been prepared from a molecular copper(I) precursor, [{(PyHS)₂CuI(PyHS)}₂](OTf)₂ (1), and utilized as an anode material in electrocatalytic OER for the first time. A hot injection of 1 yielded a pure phase and highly crystalline Cu₉S₅, which was then electrophoretically deposited (EPD) on a highly conducting nickel foam (NF) substrate. When assessed as an electrode for OER, the Cu₉S₅/NF displayed an overpotential of merely 298±3 mV at a current density of 10 mA cm⁻² in alkaline media. The overpotential recorded here supersedes the value obtained for the best reported Cu‐based as well as the benchmark precious‐metal‐based RuO₂ and IrO₂ electrocatalysts. In addition, the choronoamperometric OER indicated the superior stability of Cu₉S₅/NF, rendering its suitability as the sustainable anode material for practical feasibility. The excellent catalytic activity of Cu₉S₅ can be attributed to the formation of a crystalline CuO overlayer on the conductive Cu₉S₅ that behaves as active species to facilitate OER. This study delivers a distinct molecular precursor approach to produce highly active copper‐based catalysts that could be used as an efficient and durable OER electro(pre)catalysts relying on non‐precious metals.

An upscalable chemical vapor deposition setup has been built‐up and employed in producing methylammonium lead iodide (MAPI) thin film perovskite solar cells, leading to a maximum efficiency of 12.9%. The method makes use of methylamine gas and hydrogen iodide gas to transform a predeposited layer of lead(II)iodide (PbI₂) into MAPI. Although the reaction mechanism includes the intermediate phases lead oxide (PbO) and lead hydroxide (Pb(OH)₂), indicated at least on the surface of the samples by XPS, neither species could be observed in XRD measurements of the stepwise reaction, which show a mixture of highly oriented cubic and tetragonal MAPI perovskite lattice systems.

High power conversion efficiency (PCE) perovskite solar cells (PSCs) rely on optimal alignment of the energy bands between the perovskite absorber and the adjacent charge extraction layers. However, since most of the materials and devices of high performance are prepared by solution‐based techniques, a deposition of films with thicknesses of a few nanometers and therefore a detailed analysis of surface and interface properties remains difficult. To identify the respective photoactive interfaces, photoelectron spectroscopy measurements are performed on device stacks of methylammonium‐lead‐iodide (MAPI)‐based PSCs in classical and inverted architectures in the dark and under illumination at open‐circuit conditions. The analysis shows that vacuum‐deposited MAPI perovskite absorber layers are n‐type, independent of the architecture and of the charge transport layer that it is deposited on (n‐type SnO₂ or p‐type NiOₓ). It is found that the majority of the photovoltage is formed at the n‐MAPI/p‐HEL (hole extraction layer) junction for both architectures, highlighting the importance of this interface for further improvement of the photovoltage and therefore also the PCE. Finally, an experimentally derived band diagram of the completed devices for the dark and the illuminated case is presented.

Electroless plating is a powerful tool in nanofabrication and is available for many of the noble transition metals. There is, however, a striking lack of electroless plating procedures for the rarer platinum‐group metals. In this work, two plating baths for nanoscale iridium coatings are developed and their conformality and nanofabrication potential are showcased by coating ion‐track‐etched polycarbonate membranes, creating Ir nanotubes in the process. Both plating solutions yield morphologically different deposits, indicating that the microstructure of the film can be tuned by adjusting the composition of the plating bath. The catalytic performance of the deposited materials is investigated by using membrane‐embedded nanotubes as catalysts for the reduction of 4‐nitrophenol and methyl orange by borohydride, showing remarkable activity and stability. Operation in flow‐through configuration, in which the metallized membrane is implemented as a microreactor greatly enhances the interaction with the catalyst surface, considerably increasing product yield. The results highlight the potential of Ir nanoplating for realizing sophisticated nanostructures and heterogeneous catalysts, but also illustrate the intricacies related to the complex chemistry of electroless Ir plating baths.

The chemical selectivity and faradaic efficiency of high‐index Cu facets for the CO₂ reduction reaction (CO₂RR) is investigated. More specifically, shape‐controlled nanoparticles enclosed by Cu {hk0} facets are fabricated using Cu multilayer deposition at three distinct layer thicknesses on the surface facets of Au truncated ditetragonal nanoprisms (Au DTPs). Au DTPs are shapes enclosed by 12 high‐index {310} facets. Facet angle analysis confirms DTP geometry. Elemental mapping analysis shows Cu surface layers are uniformly distributed on the Au {310} facets of the DTPs. The 7 nm Au@Cu DTPs high‐index {hk0} facets exhibit a CH₄ : CO product ratio of almost 10 : 1 compared to a 1 : 1 ratio for the reference 7 nm Au@Cu nanoparticles (NPs). Operando Fourier transform infrared spectroscopy spectra disclose reactive adsorbed *CO as the main intermediate, whereas CO stripping experiments reveal the high‐index facets enhance the *CO formation followed by rapid desorption or hydrogenation.

Efficient base-modulated product selectivity in the aqueous-phase Ru/C-catalyzed reductive amination of 1,6-hexanediol (HDO) was reported by performing the reaction at mild conditions (463 K, 25 bar H2). High selectivity of amines could be controlled by the addition of different bases; for example, Cs2CO3 addition gave a high yield of 6-amino-1-hexanol (AH, 26%). However, the addition of Ba(OH)2 resulted in the formation of high yield of secondary amination products, hexamethylenediamine (HMDA, 34%) and azepane (26%). The hydroxide base, especially Ba(OH)2, aids in the initial conversion of HDO to AH by significantly decreasing the apparent activation energy from 68 to 48 kJ mol–1. A closer analysis of the formation of secondary products (azepane and HMDA) revealed a faster reaction between NH3 and the carbonyl-containing intermediate by the addition of Ba(OH)2 into the reaction solution.

We consider an overlapping generations model where continuous cultural traits are transmitted from an adult generation to the children. A weighted social network describes how children are influenced not only by their parents but also by other role models within the society. Parents can invest into the purposeful socialization of their children by strategically displaying a cultural trait (which need not coincide with their true cultural trait). We observe a cultural substitution effect when parents choose their behavior optimally. Based on Nash equilibrium behavior, we then study the dynamics of cultural traits throughout generations. These converge if parent’s influence on their children is large enough compared to the social environment’s influence. Under convergent dynamics, closed subgroups fully assimilate, while heterogeneous traits prevail in the other groups. Speed of convergence is low when parents' incentives to socialize their children to the own trait are high.

Since the seminal contribution of Jackson and Wolinsky (J Econ Theory 71(1):44–74, 1996) it has been widely acknowledged that the formation of social networks exhibits a general conflict between individual strategic behavior and collective outcome. What has not been studied systematically are the sources of inefficiency. We approach this omission by analyzing the role of positive and negative externalities of link formation. This yields general results that relate situations of positive externalities with stable networks that cannot be “too dense” in a well-defined sense, while situations with negative externalities tend to induce “too dense” networks. Those results are neither restricted to specific assumptions on the agents’ preferences (e.g. homogeneity), nor to a specific notion of stability or efficiency.