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Photo-induced dynamics of electronic processes are driven by the coupling between electronic and nuclear degrees of freedom. Here, we construct one- and two-dimensional organic-inorganic tin halides to investigate how dimensionality controls exciton-phonon coupling and exciton self-trapping. The results show that a one-dimensional system has strong exciton-phonon coupling leading to excitation-independent self-trapped exciton emission, whereas a two-dimensional system exhibits over ten times weaker coupling resulting in free exciton emission. The difference originates from enhanced Anderson localization in a one-dimensional system. Femtosecond transient absorption experiments directly resolve room-temperature vibrational wavepackets in a one-dimensional system, some of which propagate along the self-trapped-exciton potential energy surface. A combination of wagging and asymmetric stretching motions (~106 cm^-1) in tin iodide is identified as such a mode, inducing exciton self-trapping. While no room-temperature wavepackets are observed in a two-dimensional system. These findings uncover the interplay between dimensionality-dependent exciton-phonon coupling and electronic/nuclear dynamics, offering constructive guidance to develop multifunctional organic-inorganic metal halides.

The study of artwork is an interesting field that has undergone a major turn the last decades as the use of scientific analysis methods have increased and become a significant part of the investigations. In this study we have employed Raman spectroscopy to analyse the pigments in an old canvas painting of the Roman Emperor Domitian. The painting is of special interest since its creation is historically attributed to Tiziano Vecellio, more known as Titian, but it has recently been found to contain a signature that reads L daVinci. We here perform a rigorous pigment analysis of the painting and signature area to identify and classify the pigments by usage and the potential time of deployment. Microscopic cut outs from selected areas of the painting were analysed in a Raman microscope where 13 different pigments were identified: azurite, carbon black, chalk, cinnabar, gypsum, lead tin yellow type 1, lead white, massicot, Prussian blue, red ochre, titanium white, ultramarine and yellow ochre. Out of these, 12 pigments were contemporary with Titian (1488/90-1567) and Leonardo da Vinci (14521519), one pigment, titanium white, was present during the Roman period but came into common use at a later time and one pigment, Prussian blue, is of newer origin. Complimentary X-ray imaging shows that at least one of the areas where Prussian blue was found has likely been altered at a later stage, providing an explanation for the presence of a modern pigment in an old painting. Special emphasis was also applied to resonant and nonresonant Raman response of Prussian green and blue, expressing different ratios of Fe2+ and Fe3+ states, valuable for identification and discrimination of the compounds in pigment identification and in the more recent field of battery research.

Rational design of high-entropy intermetallic compounds (HEICs) remainschallenging due to complex structure-property relationships and the lackof predictive tools. Here, a data-driven framework is presented to evaluate thehydrogen evolution reaction (HER) activity of L1₂ -type quinary Pt₃M(4) HEICs,where M comprises any four elements from six 3d transition metals (Cr, Mn, Fe,Co, Ni, Zn). Guided by the Pm-3m space group, 15 distinct compositions with numerous microstates are designed. A deep neural network, trained on 453 computed datasets, predicts hydrogen adsorption energy (∆E_H*) across 20 000 microstructures per composition, enabling statistical mapping of site-specificperformance. To capture the effect of local atomic environments, a novelstatistical evaluation approach is introduced that quantifies the number ofmicrostates falling within the optimal ∆E_H* range, advancing beyond conven-tional mean-based evaluations. Among all candidates, Pt₃(CrMnFeCo) emergesas the most promising HER catalyst, validated experimentally over a wide pHrange. Further in-depth data mining reveals that surface Co, Cr, and Fe optimize Pt-Pt-M sites, while subsurface Ni and Co modulate Pt-Pt-Pt interactions. Thisstudy establishes a new paradigm for HEIC catalyst design and deepens themechanistic understanding of activity origin in complex multimetal systems.

Solar cells and catalysis are two important applications in the field of renewable energy where the performances of the materials in these systems are influenced by the structure and stability of the electrodes. Here, we highlight the importance of understanding the dynamic processes in electrodes, such as electrochemical reactions and surface restructuring occurring before and under the catalytic process. To ultimately understand the structure-property relation, increased understanding of the actual catalyst structure at the reaction conditions are necessary. We will outline how operando Raman spectroscopy can be utilized to unveil electrocatalyst reformulations into the active catalyst phase [1,2] and their structural integrity [3, 4]. Apart from more conventional catalysts containing only a few elements, high-entropy alloys (HEAs), composed of five or more principal elements, provide a rich landscape of local atomic arrangements that can be tuned to create tailored catalytic sites with distinct electronic and geometric properties. The enormous combinatorial space of possible compositions and microstructures makes exhaustive experimental or purely first-principles exploration infeasible. Quantum-mechanics–guided AI and machine learning are therefore essential to predict key catalytic descriptors [5], prioritize promising compositions and electrolyte environments [6-7], spectroscopic features [8] and close the loop between high-throughput computation and targeted experiments to fully elucidate HEA design rules. We will exemplify this by showing how AI and machine learning can guide us to predict optimal composition in a Pt-Based HEA for electrocatalytic hydrogen evolution, validated experimentally over a wide pH range. The catalyst required less than 12 mV overpotential at a current density of 10 mA cm−2 under alkaline conditions and less than 9 mV under acidic conditions in repeated measurements, and a mass activity up to 16.69 A mg−1Pt [9].

1. Qiu, Z., Tai, C.-W., Niklasson. G.A., Edvinsson, T. Energy & Environmental Science, 2019, 12, 572.2. Qiu, Z., Ma, Y., Edvinsson, T. Nano Energy, 2019, 66, 104118.3. Dürr, R.N., Maltoni, P., Tian, H., Jousselme, B., Hammarström, L., Edvinsson, T. ACS Nano 2020, 15, 13504.4. Dürr, R.N., Maltoni, P., Feng, S., Ghorai, S., Ström, P., Tai, C-W., Araujo, R B., Edvinsson, T.Inorg. Chem. 2024, 63, 2388.5. Araujo, R B., Pehlivan I. B., Edvinsson T. Nano Energy 2023, 105, 108027.6. Araujo, R.B., Edvinsson T, J. Mater. Chem. A 2023, 11, 1297.7. Araujo. R.B., Edvinsson, T. ACS Catal. 2024, 14, 3742.8. Araujo, R. B., Thyr, J., Pehlivan I. B., Edvinsson T. J. Chem. Phys. 2024, 161, 174711.9. Wang, Z., Chen, X., Lin, T., Zhang, B., Song, K., Gu, L., Edvinsson,T., Liu H., Araujo R.B., Yu, X. Adv. Mater. 2026, e10424.

We report a comprehensive study of the temperature-dependent structural, magnetic, vibrational, and dielectric properties of Al-substituted M-type hexaferrites SrFe_12-xAlxO₁₉. Neutron powder diffraction and Mössbauer spectrometry show that Al³⁺ preferentially replaces Fe³⁺ at spin-up octahedral sites (2a, 12k), disrupting the exchange coupling with the spin-down 4f tetrahedral sites and leading to a progressive reduction of site-specific magnetic moments and a systematic decrease in the Curie temperature, supported by temperature-dependent susceptibility measurements. Raman spectroscopy reveals pronounced phonon anomalies near T_C, particularly in modes associated with bipyramidal Fe-O vibrations, reflecting the weakening of both 4e-12k and 4e-4f exchange pathways. However, the coercive field exhibits a dramatic increase, reaching μ₀H_C ∼1.2 T for SrFe_9.6Al_2.4O₁₉, among the largest values reported for this class. Susceptibility measurements suggest that Al substitution, while weakening the superexchange network, contributes to the stabilization of single-domain behavior.

There is a great demand for efficient electromagnetic interference (EMI) shielding materials due to exponential growth in wireless telecommunication devices. These devices emit electromagnetic radiation that can disrupt electronic devices, and cause health hazards. Therefore, it is crucial to develop materials that can shield devices and humans from exposure to electromagnetic radiation. In this context, nanocomposite materials offer huge advantages due to the dual possibility of tailoring the interfaces as well as using the complementary properties of magnetic and dielectric components in the nanocomposite to enhance the EMI shielding performance. This work shows that by a careful tuning of the synthesis parameters, we can grow biphasic lithium iron oxide (ferrimagnetic α-LiFe₅O₈ and paramagnetic α-LiFeO₂) nanocomposite with different relative fractions of the two phases. The variation of the phase fraction and the simultaneous growth of the two phases allow us to control the interfaces between the two phases as well as the physical properties of the nanocomposite, which have a direct effect on the EMI shielding performance. Detailed structural (X-ray diffraction), compositional (Raman spectroscopy), and morphological (high-resolution transmission electron microscopy) characterization is presented to understand the effect of the synthesis conditions on the EMI shielding parameters. Improved dielectric and magnetic properties together with an increased number of interfaces in the sample with nearly equal amounts of the two phases results in the best performance. This work demonstrates the significant potential of using biphasic magnetic oxide nanocomposites with controllable interfaces and physical properties for EMI shielding, which can form the base for more complex triphasic systems in the future.

Lead-free metal halide perovskites are emerging as less-toxic alternatives to their lead-based counterparts. However, their applicability in optoelectronic devices is limited, and the charge transport dynamics remain poorly understood. Understanding photo-induced charge and structural dynamics is critical for unlocking the potential of these novel systems. In this work, ultrafast optical and Raman spectroscopy combined with band structure calculations are employed to investigate the coupled electronic and vibrational dynamics in Caesium gold bromide, a promising lead-free perovskite. It is found that the band-edge charge transfer states are strongly coupled to Au & horbar;Br stretching phonon modes, leading to frequency modulation of absorption by coherent phonons. Early-stage relaxation is characterized by dynamics of delocalized charge transfer excitation and slowly decaying coherent phonons. The electronic and vibrational relaxation reveals a slow formation of a localized polaronic state in the 10-20 ps timescale. Using a displaced harmonic oscillator model, the polaronic binding energy is estimated to be approximate to 80 meV following lattice relaxation along the phonon modes. Strong exciton-phonon coupling and slow polaron formation via coupling to lattice modes make this material a promising testbed for the control of coherent phonons and localized polaronic states using light.

Al₅C₃N has a nanolaminated crystal structure with layers of AlN separated by layers of Al₂C and Al₂C₂. The physical and chemical properties of Al₅C₃N is more or less unknown due to the high temperatures required to synthesize bulk samples but in analogy with other nanolaminated materials such as MAX-phases, this compound may have potential applications as thin film materials. In this study we have deposited single-phase Al₅C₃N films with magnetron sputtering onto α-Al₂O₃(001) and AlN(001)/α-Al₂O₃(001) substrates at deposition temperatures ranging from 650 °C to 800 °C. The as-sputtered films were analyzed using multiple compositional and structural characterization methods. Epitaxial growth of Al₅C₃N was obtained on AlN(001)/α-Al₂O₃(001) but with a large number of defects mainly with extra stacking planes locally inserted into the structure. Nanoindentation measurements showed a hardness of about 18–19 GPa, which is significantly harder than for the MAX-phases. This can be explained by a high bond strength between the alternating AlN and Al₂C/Al₂C₂ layers giving this compound a more three-dimensional character than the MAX-phases. The band gap measurements show band gaps of 2.2 eV and 2.9 eV for the films deposited at 650 °C, and 1.8 eV and 2.5 eV for films deposited at 800 °C.

The adoption of perovskite solar cells (PSCs) requires improved resistance to high temperatures and temperature variations. Hole-selective self-assembled monolayers (SAMs) have enabled progress in the performance of inverted PSCs, yet they may compromise temperature stability owing to desorption and weak interfacial contact. Here we developed a self-assembled bilayer by covalently interconnecting a phosphonic acid SAM with a triphenylamine upper layer. This polymerized network, formed through Friedel-Crafts alkylation, resisted thermal degradation up to 100°C for 200 h. Meanwhile, the face-on-oriented upper layer exhibited adhesive contact with perovskites, leading to a 1.7-fold improvement in adhesion energy compared with the SAM-perovskite interface. We reported power conversion efficiencies exceeding 26% for inverted PSCs. The champion devices demonstrated less than 4% and 3% efficiency loss after 2,000 h damp heat exposure (85°C and 85% relative humidity) and over 1,200 thermal cycles between -40°C and 85°C, respectively, meeting the temperature stability criteria outlined in the International Electrotechnical Commission 61215:2021 standards.

We report a rapid and controllable solid-state formation process of copper coordination complex hole-transport materials (HTMs) in dye-sensitized solar cells (DSCs), reducing processing times from over 48 h to 20 min. By thermally-induced phase transition of Cu(I/II)(tmby)2-based liquid electrolytes from 50 °C to 110 °C, we demonstrated that a 70 °C post-treatment for 20 min is ideal for creating an amorphous HTM with minimal crystallization. Time-dependent Raman spectra confirmed near-complete solvent removal within 20 min, while scanning electron microscopy highlighted a compact, defect-minimized HTM morphology when 4-tert-butylpyridine was employed versus N-methylbenzimidazole. Transient absorption spectroscopy revealed ultrafast dye regeneration (t1/2,reg = 487 ns) and near-unity regeneration efficiency (99.2%) for short heat treatments, whereas extended treatments (e.g., 60 min) led to μs-scale recombination (26.8 μs) and lower performance. Electrochemical impedance spectroscopy indicated stable charge-transfer resistances at the TiO2/HTM interface (from 25.6 Ω in liquid state to 27.5 Ω in solid state), confirming efficient hole transport pathways. Under 1 sun illumination, devices retained up to ≈10% power conversion efficiency, while indoor (1000 lux) conditions yielded photocurrents up to 79 μA cm−2 and peak efficiencies of 16%. These findings establish a robust, reproducible route to form Cu-based HTMs in solid-state DSCs with enhanced low-light performance and highlight key design parameters controlling morphology, interfacial charge transfer, and photovoltaic yield.