Michael Giese

3D-printable acrylates bearing amine groups are reported allowing the dynamic tuning of the properties of the 3D-printed objects (surface polarity, emission behavior) via imine condensation and exchange reaction on the surface of the samples.

3D-printed porous TiO₂/BiFeO₃ nanocomposite monoliths with surface areas of up to 65 m² g^-1 were fabricated via two ways employing 3D printing. In method A, BiFeO₃ nanoparticles were directly embedded into a TiO₂-based hybrid ink for the direct ink writing (DIW) technique, while in method B, BiFeO₃ nanoparticles were deposited as a surface coating onto a 3D-printed TiO₂ scaffold. The obtained materials were comprehensively characterized by X-ray diffraction (XRD), electron microscopy (SEM, TEM), nitrogen adsorption-desorption, UV-vis spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of the materials was evaluated for the degradation of acyclovir under three different irradiation conditions: a medium-pressure Hg lamp (emission mostly in the UV region, 150 W) and blue LED sources at 420 nm (6 W) and 440 nm (40 W). The sample prepared by method A, including 1 wt % BiFeO₃ inside a TiO₂ matrix, showed the best performance under all irradiation conditions, which could be attributed to the combination of high surface area and the improved charge separation across the heterojunction interface. Additionally, Density Functional Theory (DFT) calculations were performed to confirm the formation of type-II heterojunctions between BiFeO₃ embedded in TiO₂ materials, consistent with the experimentally observed enhancement. These 3D-printed materials represent a significant advancement toward the development of photocatalytic water treatment under visible light conditions.

Control over the circular polarization of emitted light is important for advanced photonic applications, but organic emitters often show weak intrinsic chiroptical responses, limiting their technological application. In this work,...

The development of responsive molecules enables the design of novel smart materials for numerous applications. A series of new arylazopyrazoles is designed as dopants for commercially available liquid crystal hosts and their photoresponse in solution and mesophases is investigated. Furthermore, the solid‐state structure in single‐crystal diffraction is analyzed to gain insight into possible intermolecular interactions of the photoswitches with LC host materials, thus anticipating the effect of photoswitching in the LC phase. Additionally, 3,5‐difluorophenol is implemented as a hydrogen‐bond donor to tune the impact of the photoisomers on the mesogenic behavior. Unprecedented, reversible control of the distribution of E ‐ and Z ‐isomers at the photostationary state of different wavelengths (365, 460, and 520nm) is utilized to induce phase transitions of liquid crystals. This strategy allows for the controlled transition between smectic, nematic, and isotropic phases at isothermic conditions by irradiation with the corresponding wavelength ‐ a new concept in the design of photoresponsive materials.

When visual representations of molecules ( e.g. , skeletal formula) must be decoded to process a task ( e.g. , determine the absolute configuration of a molecule) and the corresponding schemas are not yet sufficiently automated, paper–pencil format notes may help select relevant information, organize it appropriately, and integrate knowledge without exceeding the working memory capacity (encoding and external storage). This article examines the extent to which task difficulty and invested mental effort differ for digital and paper–pencil-based tasks on the topic of chirality (RQ1) and the extent to which note-taking impacts students’ working memory load when working on paper–pencil-based chirality tasks (RQ2). The dataset is based on the responses of 80 students from Germany who completed 19 chirality task tandems (each consisting of one digital and one paper–pencil-based task) and rated their invested mental effort for each task. Item response theory analyses, group comparisons, and moderation analyses were conducted. Paper–pencil-based chirality tasks were found to be significantly easier than digital chirality tasks, and students invested significantly less mental effort in completing the paper–pencil-based chirality tasks (RQ1). Students who took notes in the paper–pencil format were found to be more capable of solving chirality tasks in both formats. Both groups invested a comparable amount of mental effort. A moderation analysis revealed that when note-taking was low, the relationship between invested mental effort and the probability of solving the task was strongest. For the note-takers, the relationship between the invested mental effort and the probability of solving the task decreased as the number of notes increased (RQ2). The results indicate that notes as external storage are relevant for processing tasks requiring handling representation. As the digital format does not offer comparable options for taking notes, notes represent a subject-specific format difference.

The unique combination of two classes of luminophores, showing either aggregation-induced or aggregation-caused quenching within a liquid crystal yielded a thermo-sensor with a temperature induced emission shift from green to red.

Discovering the versatile ability of environment-independent solution and solid-state emission (SSSE) enabled new possibilities of fine-tuning photophysical properties, targeting specific organelles, or developing remarkable materials. Herein, we report an unprecedented design concept for SSSE by employing the “magic methyl” effect in a series of alkylated heteropentacyclic luminophores R8, Y8, and G8. Implementing an increasing amount of ortho-methyl groups influences the vertical electronic transitions, tuning the emission colors from red over yellow to green and inverting the preferred state of luminescence from solution to solely the solid-state or even both. An in-depth analysis was performed using X-ray diffractometric structure elucidation, packing analysis and density functional theory calculations to correlate the photophysical properties with the steric pressure induced by the methyl groups. Additionally, the application scope of these new materials was investigated. Mesoporous silica nanoparticles loaded with the three new luminophores were prepared and employed as additives for 3D printing using digital light processing. Ultimately, these stimuli-responsive molecules performed as optical sensors of microenvironmental temperature and phase transition changes in liquid crystals.

Ultrasmall gold nanoparticles (2 nm) were surface‐coated with photoswitchable 3‐azopyridine ligands by ligand exchange with n‐dodecanethiol‐stabilized gold nanoparticles. Each gold nanoparticle carried about 66 dodecanethiol (DDT) ligands and 49 azo ligands. The azo ligands were reversibly switchable between the stable E ‐ and the metastable Z ‐isomer by UV and green light irradiation as shown by UV‐Vis and NMR spectroscopy. The photoswitching was not significantly affected by the conjugation of the azo ligand to the nanoparticle surface, despite the high density of ligands on the particle surface. This offers a pathway for photoswitchable systems on the nanoscale, for example, to manipulate supramolecular systems. The introduction of 0.5 wt% of the nanoparticles into a liquid crystalline host yielded a photoresponsive material which showed a reversible nematic‐to‐isotropic phase transition upon irradiation

In this study, we present the synthesis and a versatile way to incorporate photoresponsive organic luminophores into polymeric materials using mesoporous silica nanoparticles (MSNs). The encapsulated thioethers within the MSNs were employed in polyvinyl alcohol (PVA) films, resin‐based stereolithography, and electrospinning. Due to light‐induced cyclisation to dibenzothiophenes (DBTs), mmOC₁₂ loaded materials were used to inscribe images using UV light. The DBTs formed from mmOC₁₂ (mmDBT_A/B) exhibit a long phosphorescence afterglow, which was investigated by steady‐state and time‐resolved photoluminescence spectroscopy. In addition, scanning electron microscopy (SEM) imaging, including energy dispersive X‐ray spectroscopy (EDX), revealed the well‐dispersed and intact MSNs in the polymeric materials. This approach shows a general way to incorporate non‐polar organic luminophores into polymeric materials while retaining their unique emission properties.