EXPlainistry: Creating Documentation, Explanations, and Animated Visualizations of Chemistry Experiments Supported by Information and Communication Technology to Help School Students Understand Molecular-Level Interactions

Given that students are constantly communicating and documenting special experiences in their social and private lives with digital devices, we suggest that this behavior could be used to record and deepen learning experiences-such as visualizing reactions at the molecular level-in a chemistry class. An example would be the creation of stop-motion videos to aid the visualization process for the documentation of experiments. This approach makes use of well-established techniques for documentation and visualization (e.g., static models or pictures) and combines them with dynamic approaches (e.g., animations) in order to enhance explanations of chemical experiments. Here, we describe how we use this approach to augment the novel teaching method, EXPlainistry (experiments explained in chemistry) with 5th to 12th graders, and consider how it helps students use ICT (information and communications technology) in order to document, explain, and visualize experiments in chemistry education

Pentacene in 1,3,5-Tri(1-naphtyl)benzene: A Novel Standard for Transient EPR Spectroscopy at Room Temperature

Testing and calibrating an experimental setup with standard samples is an essential aspect of scientific research. Single crystals of pentacene in p-terphenyl are widely used for this purpose in transient electron paramagnetic resonance (EPR) spectroscopy. However, this sample is not without downsides: the crystals need to be grown and the EPR transitions only appear at particular orientations of the crystal with respect to the external magnetic field. An alternative host for pentacene is the glass-forming 1,3,5-tri(1-naphtyl)benzene (TNB). Due to the high glass transition point of TNB, an amorphous glass containing randomly oriented pentacene molecules is obtained at room temperature. Here we demonstrate that pentacene dissolved in TNB gives a typical “powder-like” transient EPR spectrum of the triplet state following pulsed laser excitation. From the two-dimensional data set, it is straightforward to obtain the zero-field splitting parameters and relative populations by spectral simulation as well as the B1 field in the microwave resonator. Due to the simplicity of preparation, handling and stability, this system is ideal for adjusting the laser beam with respect to the microwave resonator and for introducing students to transient EPR spectroscopy

Promoting Education for Sustainable Development with an Interactive Digital Learning Companion Students Use to Perform Collaborative Phosphorus Recovery Experiments and Reporting

Multitouch learning books (MLBs) are learning companions that support learning within a series, independent of the learning location. These MLBs can accompany an experiment itself or an entire learning process. In addition to providing interactive tasks, an all-in-one solution can provide pupils with additional information, supporting and differentiating aids, in-depth exercises, and collaborative tasks in one location. This Article presents an interactive learning companion that facilitates student learning through digital interaction while also developing concepts of sustainability in students’ minds. For this purpose, a learning scenario was developed that simulates a virtual learning company in an interactive e-book that corresponds to real experiments carried out in a laboratory. Using this interactive e-book, pupils receive e-mail messages from their “supervisors,” give account to the “board of directors,” and finally evaluate four real processes for phosphorus recovery. The entire series was qualitatively tested with 89 tenth-grade students. Assessment of these students found a significant increase in their use and understanding of digital tools and awareness of education for sustainable development concepts

Multitouch Experiment Instruction and Self-Regulation: Promoting Self-Regulation with a Multitouch Experiment Instruction on the topic of water analysis

In context of Education for Sustainable Development (ESD), the range of experiments offered by the Schülerlabor NanoBioLab at Saarland University was expanded to include an experiment on the topic of water analysis, which provided the basis of the intervention. In addition to the analogue experiment instruction, there is a digital version which is presented as a Multitouch Experiment Instruction (MEI). MEIs are digitally enriched, interactive experiment instructions that accompany the cognitive learning process of pupils and promote competencies in the digital world (Seibert et al., 2020). In this study, we analysed whether the MEI could support self-regulated learning in an indirect support approach by considering different hierarchical levels of self-regulation in the design of the materials. The results show a significant acquisition of self-regulatory competences of learners in grades ten and eleven by using the MEI compared to the analogue version

Multitouch Experiment Instructions to Promote Self-Regulation in Inquiry-Based Learning in School Laboratories

Multitouch experiment instructions (MEIs), implemented as interactive eBooks, are learning tools for pupils that offer various digital support tools and enable pupils to individualize their learning. They may be applied to contexts such as inquiry-based experiments in school laboratories, which involve highly demanding cognitive processes and require a high level of self-regulation. Self-regulation has been shown to be reliably promoted by interventions which include the targeted training of self-regulation strategies. A MEI was designed as an interactive eBook on experiments on the topic “Analysis of Cola”, suitable for an inquiry-based learning environment such as a school lab. The MEI’s potential to promote self-regulated learning was investigated by comparing it to a MEI with digital, integrated self-regulation training. The data revealed a significant increase of self-regulation in the control group, which consisted of pupils experimenting with the MEI on its own, and one experimental group, which included pupils that were supported by the MEI with an additional self-regulation training. It can be assumed that the MEI’s ability to promote self-regulated learning is comparable to the results achieved by an additional self-regulation training which explicitly addressed self-regulation strategies. This highlights the MEI’s potential to promote self-regulated learning in an indirect approach

Maser threshold characterization by resonator Q-factor tuning

Whereas the laser is nowadays an ubiquitous technology, applications for its microwave analog, the maser, remain highly specialized, despite the excellent low-noise microwave amplification properties. The widespread application of masers is typically limited by the need of cryogenic temperatures. The recent realization of a continuous-wave room-temperature maser, using NV− centers in diamond, is a first step towards establishing the maser as a potential platform for microwave research and development, yet its design is far from optimal. Here, we design and construct an optimized setup able to characterize the operating space of a maser using NV− centers. We focus on the interplay of two key parameters for emission of microwave photons: the quality factor of the microwave resonator and the degree of spin level-inversion. We characterize the performance of the maser as a function of these two parameters, identifying the parameter space of operation and highlighting the requirements for maximal continuous microwave emission

An “interaction-mediating” strategy towards enhanced solubility and redox properties of organics for aqueous flow batteries

Aqueous redox flow batteries using electroactive organic materials are currently attracting significant attention. However, the influence of supporting electrolytes on the aqueous solubility, electrochemical reversibility and chemical stability of the organic components has rarely been investigated. Here, a new electrolyte design strategy towards enhanced solubility and chemical stability of active materials is proposed by using interaction-mediating species. 3 molality aqueous imidazolium chlorides, with high ionic conductivity and water-like flowability, enable a record aqueous solubility of 4.3 M for a commercially available nitroxyl radical and reversible 2e^{-} reaction of unmodified methyl viologen at moderate concentrations. With 0.6 M electrolyte, flow cell shows remarkable chemical stability of the nitroxyl radical, excellent cycling stability over 250 cycles at 80 mA cm^{-2}, and a peak power density of 121.6 mW cm^{-2} at 175 mA cm^{-2}. Furthermore, nitroxyl radical catholyte with a concentration of 3 M is tested in a flow cell. It maintains an impressive steady energy efficiency of 65% at 30 mA cm^{-2}. This work paves a new way for the development of high performance aqueous electrolytes based on organic materials

Effects of Cationic Species in Salts on the Electrical Conductivity of Doped PEDOT:PSS Films

The electrical conductivity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films with four salts that have various cations but the same bis(trifluoromethanesulfonyl)amide (TFSI) anion was studied. We found that doping salts of small-sized cations led to better conductivity because of the improved crystalline order and p-doped level of PEDOT, as revealed by the grazing-incidence wide-angle X-ray scattering (GIWAXS) and UV-vis spectrum. This phenomenon can be rationalized with the fact that small-sized cations with stronger Coulombic interactions can lead to high doping and rearrangement of PEDOT:PSS. These findings will help to develop recipes based on the PEDOT:PSS/salt composite toward the applications for printed flexible electronics

High-temperature antiferromagnetism in molecular semiconductor thin films and nanostructures

The viability of dilute magnetic semiconductors in applications is linked to the strength of the magnetic couplings, and room temperature operation is still elusive in standard inorganic systems. Molecular semiconductors are emerging as an alternative due to their long spin-relaxation times and ease of processing, but, with the notable exception of vanadium-tetracyanoethylene, magnetic transition temperatures remain well below the boiling point of liquid nitrogen. Here we show that thin films and powders of the molecular semiconductor cobalt phthalocyanine exhibit strong antiferromagnetic coupling, with an exchange energy reaching 100 K. This interaction is up to two orders of magnitude larger than in related phthalocyanines and can be obtained on flexible plastic substrates, under conditions compatible with routine organic electronic device fabrication. Ab initio calculations show that coupling is achieved via superexchange between the singly occupied a(1g) ([Image: see text]) orbitals. By reaching the key milestone of magnetic coupling above 77 K, these results establish quantum spin chains as a potentially useable feature of molecular films

Dynamics, cation conformation and rotamers in guanidinium ionic liquids with ether groups

Ionic liquids are modern materials with a broad range of applications, including electrochemical devices, the exploitation of sustainable resources and chemical processing. Expanding the chemical space to include novel ion classes allows for the elucidation of novel structure-property relationships and fine tuning for specific applications. We prepared a set of ionic liquids based on the sparsely investigated pentamethyl guanidinium cation with a 2-ethoxy-ethyl side chain in combination with a series of frequently used anions. The resulting properties are compared to a cation with a pentyl side chain lacking ether functionalization. We measured the thermal transitions and transport properties to estimate the performance and trends of this cation class. The samples with imide-type anions form liquids at ambient temperature, and show good transport properties, comparable to imidazolium or ammonium ionic liquids. Despite the dynamics being significantly accelerated, ether functionalization of the cation favors the formation of crystalline solids. Single crystal structure analysis, ab initio calculations and variable temperature nuclear magnetic resonance measurements (VT-NMR) revealed that cation conformations for the ether- and alkyl-chain-substituted are different in both the solid and liquid states. While ether containing cations adopt compact, curled structures, those with pentyl side chains are linear. The Eyring plot revealed that the curled conformation is accompanied by a higher activation energy for rotation around the carbon-nitrogen bonds, due to the coordination of the ether chain as observed by VT-NMR