In the field of forensic science, we have recently introduced Raman imaging as a promising nondestructive technique to efficiently recover obliterated serial numbers in polycarbonate. The present study is extending the investigation toward different polymers for the reconstruction of abraded information by Raman spectroscopy. Samples of polyethylene, nylon, and nylatron, which are mainly used in items such as firearms, banknotes, and package materials, are investigated by monitoring the vibrational modes which are most susceptible to peak shifts and changes in the full width at half-maximum (fwhm) and peak intensity ratios. In all cases, the most affected peak depends on the polymer’s 3D structure and displays a ∼1 cm–1 shift and a broadening above ∼2 cm–1, as well as a relative intensity change of over 50%, more than enough for a successful recovery through confocal imaging. Depending on the polymer’s structural arrangement, any of the three contributions prevails for the strongest contrast. The propagation of the plastic deformations is mainly affected by the Young’s modulus of the material, due to a change in its elasticity. The shift, the width, and the relative intensity of the Raman peaks being three independent parameters, they can be correlated to enhance the contrast and thus to accelerate the image acquisition or to enhance statistical significance.

While machine learning algorithms are becoming more and more elaborate, their underlying artificial neural networks most often still rely on the binary von Neumann computer architecture. However, artificial neural networks access their full potential when combined with gradually switchable artificial synapses. Herein, complementary metal oxide semiconductor-compatible Hf 0.5 Zr 0.5 O 2 ferroelectric tunnel junctions fabricated by radio-frequency magnetron sputtering are used as artificial synapses. On a single synapse level, their neuromorphic behavior is quantitatively investigated with spike-timing-dependent plasticity. It is found that the learning rate of the synapses mainly depends on the voltage amplitude of the applied stimulus. The experimental findings are well reproduced with simulations based on the nucleation-limited-switching model.

Noble‐metal‐free catalytic nanoparticles hold the promise being abundant, low‐cost materials having a small environmental footprint and excellent performance, albeit inferior to that of noble metal counterparts. Several materials have a long‐standing history of success in photocatalysis, in particular titanium dioxide, and in recent years more complex oxides and added functionality have emerged with enhanced performance. We will discuss different approaches related to the use of non‐centrosymmetric and polar oxide nanoparticles and how the bulk photovoltaic effect, piezoelectricity, and pyroelectricity add to photocatalysis and tribocatalysis. We pay special attention to discriminate between the role of free versus that of bound charges within the catalyst, which is crucial to disentangle the different contributions to the catalytic reaction for the benefit of the overall enhanced catalytic performance in e.g. wastewater treatment and ultimately water‐splitting.