Dorothea Wisser

Heterogenized molecular catalysts commonly rely on covalent grafting to solid supports. Cleavage of these linkages under catalytic conditions, however, can compromise structural definition and control at the interface. Here, we introduce a ligand‐encoded anchoring strategy in which a platinum(II) bis(NHC) complex is immobilized on mesoporous silica (SBA‐15) exclusively through directional, non‐covalent F–Si interactions. The molecular pre‐catalyst trans ‐[Pt(L ^F ) ₂ Cl ₂ ] was structurally characterized by single‐crystal X‐ray diffraction and multinuclear solution‐state NMR spectroscopy. Advanced solid‐state MAS NMR experiments, including ¹⁹ F{ ²⁹ Si} REDOR, combined with molecular dynamics simulations, establish well‐defined F–Si contacts with internuclear distances on the Å‐scale and reveal the organization of the pre‐catalyst at the silica interface. A model hydrosilylation reaction demonstrates catalytic activity and retention of the molecular species on the support during turnover. This work establishes non‐covalent interface engineering as a viable strategy for structurally defined heterogenized catalysis.

Flexible lead‐halide perovskite solar modules with carbon electrodes (C‐fPSMs) are promising for printed photovoltaics due to their low cost and compatibility with roll‐to‐roll (R2R) fabrication. However, the mechanical fragility of microcrystalline perovskite films, arising from their high grain‐boundary density, limits their practical application. Here, we report a vapor‐phase grain‐boundary anchoring strategy via thiol vapor annealing to molecularly toughen printed perovskite layers. Thiol molecules interact with intermediate species and preferentially anchor at surfaces and grain boundaries, reprogramming crystallization across the film. This chemomechanical conditioning promotes grain growth, reduces trap density, and transforms the deformation behavior from brittle fracture to ductile strain accommodation, as evidenced by reduced Young's modulus, increased yield strain, and significantly enhanced fracture toughness. As a result, treated devices retain 93% of their initial performance after 25 000 bending cycles, representing a new benchmark for flexible perovskite cells. In addition, improved film uniformity and interfacial contact enable power conversion efficiencies of 15.7% for R2R‐printed cells and 12.1% for modules (20.25 cm ² ), with scalability demonstrated up to 900 cm ² (17.26%). This work provides a scalable strategy to simultaneously enhance mechanical robustness and photovoltaic performance.

Flexible lead‐halide perovskite solar modules with carbon electrodes (C‐fPSMs) are promising for printed photovoltaics due to their low cost and compatibility with roll‐to‐roll (R2R) fabrication. However, the mechanical fragility of microcrystalline perovskite films, arising from their high grain‐boundary density, limits their practical application. Here, we report a vapor‐phase grain‐boundary anchoring strategy via thiol vapor annealing to molecularly toughen printed perovskite layers. Thiol molecules interact with intermediate species and preferentially anchor at surfaces and grain boundaries, reprogramming crystallization across the film. This chemomechanical conditioning promotes grain growth, reduces trap density, and transforms the deformation behavior from brittle fracture to ductile strain accommodation, as evidenced by reduced Young's modulus, increased yield strain, and significantly enhanced fracture toughness. As a result, treated devices retain 93% of their initial performance after 25 000 bending cycles, representing a new benchmark for flexible perovskite cells. In addition, improved film uniformity and interfacial contact enable power conversion efficiencies of 15.7% for R2R‐printed cells and 12.1% for modules (20.25 cm ² ), with scalability demonstrated up to 900 cm ² (17.26%). This work provides a scalable strategy to simultaneously enhance mechanical robustness and photovoltaic performance.

Solid‐state nuclear magnetic resonance spectroscopy under Magic Angle Spinning (MAS) is one of the most powerful analytic techniques and in principle the method of choice to elucidate with molecular detail all components of complex solid or solid‐liquid samples. MAS NMR under light irradiation is yet little developed, with technical solutions and first applications just emerging. We present the first operando observation of photoreforming of methanol to formaldehyde in a transparent rotor, irradiated at 365 nm by four LEDs, at spinning rates up to 11.5 kHz. The photon flux inside the rotor is quantified by an actinometric reaction. Efficient light penetration into the entire rotor volume is crucial. Therefore, we introduce silica monoliths with a continuous network of macropores, coated with TiO ₂ (anatase) as supported heterogeneous catalyst. These monoliths provide a large pore volume to accommodate the liquid substrate and a high surface area. Centrally, the network of pores larger than the visible light enhances light penetration into the material by a factor of two compared to a powder. Silica monoliths may be easily decorated with various photocatalysts and thus provide a versatile platform for observing in real time photocatalytic reactions by solid‐state NMR.

Unprecedented insight into the lanthanide dispersion in mixed-metal Eu _x Tb _{1− x} BTC using high-field ¹ H MAS NMR spectroscopy. Isolation of Eu sites in the TbBTC matrix leads to efficient Tb-to-Eu energy transfer and high temperature sensitivity near RT.

Separation and reuse of the catalytically active metal complexes are persistent issues in homogeneous catalysis. Supported Ionic Liquid Phase (SILP) catalysts, where the catalytic center is dissolved in a thin film of a stable ionic liquid, deposited on a solid support, present a promising alternative. However, the dissolution of the metal center in the film leaves little control over its position and its activity. We present here four novel, task‐specific ionic liquids [FPh_nIm^HR]I (n=1, 2; R=PEG₂, C₁₂H₂₅), designed to self‐assemble on a silica surface without any covalent bonding and offering a metal binding site in a controlled distance to the support. Advanced multinuclear solid‐state NMR spectroscopic techniques under Magic Angle Spinning, complemented by molecular dynamics (MD) simulations, allow us to determine their molecular conformation when deposited inside SBA‐15 as a model silica support. We provide here conceptual proof for a rational design of ionic liquids self‐assembling into thin films, opening an avenue for a second, improved generation of SILP catalysts.

We have developed a comprehensive strategy for quantitatively assessing the hydrophilicity/ hydrophobicity of nanoporous materials by combining advanced adsorption studies, novel liquid intrusion techniques and solid-state NMR spectroscopy. For this we have chosen a well-defined system of model materials, i.e., the highly ordered mesoporous silica molecular sieve SBA-15 in its pristine state and functionalized with different amounts of trimethylsilyl groups allowing one to accurately tailor the surface chemistry while maintaining the well-defined pore structure. For an absolute quantification of the trimethylsilyl group density, quantitative 1H solid-state NMR spectroscopy under Magic Angle Spinning was employed. A full textural characterization of the materials was obtained by high-resolution argon 87 K adsorption, coupled with the application of dedicated methods based on non-local-density functional theory (NLDFT). Based on the known texture of the model materials, we developed a novel methodology allowing one to determine the effective contact angle of water adsorbed on the pore surfaces from complete wetting to non-wetting, constituting a powerful parameter for the characterization of the surface chemistry inside porous materials. The surface chemistry was found to vary from hydrophilic to hydrophobic with increasing TMS functionalization. For wetting and partial wetting surfaces, pore condensation of water is observed at pressures P smaller than the bulk saturation pressure P0 (i.e., at P/P0 1). In this case we investigated the pore filling of water (i.e. the vapour-liquid phase transition) by the application of a novel, liquid water intrusion/extrusion methodology, allowing one to derive the effective contact angel of water on the pore walls even in case of non-wetting. Complementary molecular simulations provide density profiles of water on pristine and TMS-grafted silica surfaces (mimicking the tailored, functionalized experimental silica surfaces) which allow for a molecular view on the adsorbed water phase. Within this context, the presented methodology can be considered a powerful toolbox for a comprehensive surface chemistry assessment for pristine and functionalized mesoporous silica surfaces, but can also be extended to any other nanoporous material. It has the potential to provide important guidance for the design and selection of porous materials for various applications including separation applications (such as chromatography), heterogeneous catalysis etc.