Antimony sulfide (Sb_2S_3) is a semiconductor composed of quasi-one-dimensional ribbon-like structural units, which give rise to pronounced structural anisotropy in the bulk crystal. Despite growing interest in Sb_2S_3, in particular Sb_2S_3 thin films, a detailed understanding of its symmetry-based lattice dynamics remains incomplete. Here, we present a combined experimental and theoretical study of polarization-dependent Raman scattering in Sb_2S_3 thin films. We derive the Raman selection rules from the crystal symmetry and calculate the zone-center phonon modes and corresponding Raman tensors using density functional theory. The calculated polarization dependencies are systematically compared with polarization-dependent Raman measurements performed on oriented crystalline domains of Sb_2S_3 thin films. This combined analysis enables reliable mode assignments, elucidates the anisotropic Raman response associated with the ribbon-like crystal structure, and demonstrates the sensitivity of polarized Raman spectroscopy to crystal orientation and structural order in antimony chalcogenide (Sb_2S_3, Sb_2Se_3) as well as isostructural Bi_2S_3 thin films.

Understanding the decomposition and reaction mechanisms of sulfur precursors used in organometallic colloidal synthesis is critical for controlling the nucleation and growth of nanocrystals. In this work, we investigate the thermal decomposition of thiourea and various N,N '-substituted thioureas in oleylamine to elucidate their distinct decomposition mechanisms, sulfur release pathways, and the implications for strontium sulfide (SrS) nanoparticle syntheses due to these decompositions. Using a combination of in situ quadrupole mass spectrometry (QMS), NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), thermogravimetry (TGA), and DFT-calculated bond dissociation energies (BDEs), our findings reveal that substituent identity and symmetry significantly affect the decomposition onset temperatures and reaction intermediates. Unsubstituted thiourea undergoes initial isomerization with two competing subsequent fragmentation routes, releasing the gaseous products H2S and NH3, respectively. The other fragments from both routes, carbodiimide and isothiocyanic acid, react with oleylamine to form N,N '-dioleylthiourea. The N,N '-dioleylthiourea undergoes a second decomposition process, which releases H2S and the trisubstituted guanidine. Aliphatic N,N '-substituted thioureas exhibit the first fragmentation process, which releases the respective alkylamine, whereby the various chain-length substituents influence the decomposition onset temperature and the decomposition process, which releases H2S from N,N '-dioleylthiourea. Aromatic N,N '-substituted thioureas follow the same sequential decomposition mechanism, but resonance effects in N,N '-diphenylthiourea lower the decomposition temperature. These mechanistic differences are then directly correlated with the formation of strontium sulfide (SrS) nanocrystals. By tracking sulfur and amine release during synthesis, we show that the timing and concentration of reactive sulfur species, such as H2S, determine the nucleation rate, particle size, and morphology of the resulting nanocrystals. This study provides mechanistic insights into thiourea decomposition in oleylamine and establishes a direct link between the precursor structure and nanoparticle outcome. The results lay the foundation for more predictive and tunable synthesis strategies in the design of colloidal metal sulfide nanomaterials.

Lines of indium(III) sulfides are deposited by atomic-layer additive manufacturing (ALAM) based on the reaction of indium tris(acetylacetonate) with hydrogen sulfide established in atomic layer deposition (ALD). At 160 °C, solid accretion occurs at a rate of 0.04 Å per pass. The layers are continuous, free of observable pinholes, dense, and very smooth, with a root-mean-squares roughness on the order of 0.5 nm found for deposits up to 25 nm thick. The material is nearly stoichiometric, with a S/. In ratio of 1.6 found experimentally by energy-dispersive X-ray microanalysis in cross-section examination by transmission electron microscopy, and it is polycrystalline. This work delivers In2S3 as a dopant or interfacial layer in opto-electronic devices to be prototyped and optimized by ALAM.

In this study, we conduct a comprehensive analysis of the energy storage and release of water-soluble 2,5-norbornadiene-2,3-dicarboxylic acid (DC-NBD) integrating spectroscopic characterization, pH-dependent speciation, and photochemical response analysis. We evaluate protonation and dimerization equilibria using potentiometric and 1H-NMR techniques, revealing three well-defined pH intervals that affect the reactivity and stability of the system. The photoinduced conversion of DC-NBD to DC-QC was investigated at different pH conditions, while the catalytic back-conversion of the most stable quadricyclane species (DC-QC2-) was evaluated on Au(111) and Pt(111) single-crystal surfaces by time-resolved photochemical infrared reflection absorption spectroscopy (PC-IRRAS) and density functional theory. Our findings demonstrate that photoisomerization and catalytic back-conversion can be efficiently conducted in an aqueous environment, eliminating the need for organic solvents. This study advances the development of water-soluble MOST systems, offering key insights into the molecular design and optimization of sustainable photoactive materials. Future research should focus on enhancing photochemical efficiency, improving long-term stability, searching for more active catalysts and scaling these systems for practical solar energy storage applications.

Abstract The most conventional atomic layer processing method, atomic layer deposition (ALD), delivers ultrathin blanket coatings with sub-nanometer thickness precision. Lateral confinement underpins the direct atomic layer processing (DALP®) family of deposition techniques. ALD chemistry applied to DALP® is a 3D printing method called atomic-layer additive manufacturing (ALAM). Here, we demonstrate the applicability of ALAM to the additive buildup of the crucial ZnS / Sb2S3 / V2O5 semiconductor stack which constitutes an functional inorganic solar cell. To this goal, ALAM processes are first optimized and evaluated for the individual materials vanadium(V) oxide, zinc sulfide, and antimony(III) sulfide. We establish the layer-by-layer growth mode controlled by self-limiting surface chemistry and characterize the materials’ structure and the smooth surface morphology of ALAM-coated areas. Finally, all three materials are 3D-printed in ALAM mode in combination with electrodes and the electron acceptor titania (TiO2) to form functional solar cells with a 120 nm thick Sb2S3 absorber layer. This novel fabrication of solar cells highlights the advantages of using direct patterning in the prototyping and optimization of photovoltaics in research and development.

ABSTRACT Conducting polymers are widely used in bioelectronic interfaces because of their mixed ionic-electronic conductivity, mechanical compliance, and compatibility with biological systems. However, their electrochemically driven structural dynamics have received little attention as a mechanism for mechanical cell stimulation. Here, we show that electrochemical actuation of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) generates mechanical cues capable of activating endogenous mechanosensitive pathways in HEK293T cells. Transparent PEDOT:PSS films deposited on ITO exhibited a heterogeneous granular morphology and underwent potential-dependent microscopic deformation during electrochemical modulation. Direct optical tracking revealed displacement of the polymer boundary, with structural changes occurring preferentially in polymer-dense regions and propagating toward the film edge. When HEK293T cells were cultured directly on PEDOT:PSS, repeated electrochemical stimulation at -240 mV produced reproducible intracellular Ca 2+ responses. Pharmacological inhibition with GsMTx4 attenuated the calcium response, whereas blockade of voltage-gated sodium channels with tetrodotoxin largely preserved it, supporting the involvement of mechanosensitive pathways in the cellular response. These findings identify PEDOT:PSS as an electromechanical biointerface in which electrochemical modulation can introduce a mechanical component alongside the established electrical function of the interface. This mechanical contribution should therefore be considered when interpreting cellular responses to conducting polymer- based electrical stimulation and provides a basis for engineering bioelectronic interfaces that deliberately couple electrical control with mechanotransduction.

Abstract Fused filament fabrication (FFF) 3D printing provides an accessible route to fabricating retrievable photocatalytic architectures with tunable geometry and composition. Here, we address the limited recoverability and reusability of conventional powder-based photocatalysts by translating a metal-free semiconductor catalyst to 3D printed electrodes. Graphitic carbon nitride (g-C3N4) was functionalized with carbonized polydopamine (cPDA) to create a modified photocatalyst with improved photophysical behavior, consistent, more effective charge separation, and longer-lived photoexcited states, which correlates with enhanced photocatalytic activity. The optimized formulation was compounded into an extrudable PLA-based composite filament and printed into electrodes containing either g-C3N4 or g-C3N4/cPDA. The printed g-C3N4/cPDA electrodes show enhanced photocatalytic rhodamine B degradation under simulated sunlight compared with unmodified printed electrodes. In contrast to suspended powders, the electrodes enable straightforward retrieval, improved operational stability, and reuse without postseparation steps. Furthermore, we demonstrate that electrode performance can be increased by scaling the surface area, highlighting geometry as a simple handle for upscaling. This work demonstrates the potential of photocatalytic 3D printed electrodes made from abundant materials via low-energy processing as a scalable and sustainable route for wastewater treatment.

Perovskite solar cells (PSCs) experience significant photovoltage losses due to nonradiative recombination, especially in p-i-n devices with Fullerene C60 as the electron transport layer (ETL), which limits device performance. To tackle this issue, we propose a strategy that synergistically suppresses nonradiative recombination at the perovskite/C60 interface by employing a 2D heterointerface with a two-site anchor bridge, which reduces the surface defect density. This process elevates the fermi level and enhances the electric field, facilitating electron extraction at the perovskite/C60 heterointerface. As a result, nonradiative recombination at this electron-selective perovskite contact is greatly suppressed. p-i-n PSCs fabricated using this interface engineering approach achieved a power conversion efficiency (PCE) of 26.32% and demonstrated excellent stability under continuous maximum power point tracking, along with an open-circuit voltage (Voc) of 1.217 V. This broadly applicable and scalable approach further delivers an impressive Voc of up to 1.368 V in wide-bandgap (1.8 eV) devices. Overall, the strategy offers a viable pathway toward efficient and stable inverted PSCs, demonstrating broad compatibility with diverse perovskite compositions.

Printable rear electrodes represent a key enabling technology for the upscaling of perovskite solar cells (PSCs). Carbon electrodes are appealing candidates widely employed in n-i-p (so-called “conventional”) architectures, but their integration into p-i-n (so-called “inverted”) architectures is prohibited by interfacial energetic mismatch. We address this challenge by introducing a tin oxide (SnOx) interlayer with desirable mechanical durability and n-doping level. We show in detail how the tailored interlayer converts carbon from a hole-collecting anode to an electron-collecting cathode and how the electron-extraction barrier is minimized, narrowing the efficiency gap between carbon (21.8%) and silver (24.0%) electrodes. The advancement results in a remarkably improved viability of the PSCs: a modest drop in efficiency is outweighed by a 3-fold improvement in projected operational lifetime (>8,000 h) and a 60% reduction in the bill of materials. These results underscore the potential of carbon as a cost-effective alternative to silver in the industrialization of p-i-n PSCs.

Semiconductor nanoparticles (NPs), such as those of nickel oxide (NiO), exhibit catalytic activity toward the urea oxidation reaction (UOR), making it an attractive alternative to the kinetically slow oxygen evolution reaction (OER). Such nanomaterials have demonstrated improved electrochemical performance but experience a transformation in their electronic (defect) structure compared to bulk materials. Thus, we combine optoelectronic transient absorption (TA) with electrochemical characterization to understand the relations of electronic defect structures and morphology to the electrochemical performance of nanosized catalysts. Two distinct syntheses were performed: (I) a sol-gel Ni(OH)2 approach with subsequent calcination, forming mesoporous NiO particles, and (II) an organometallic colloidal NiO NP route. Successful formation of NiO was confirmed for all syntheses by X-ray diffraction, and morphology was explored by scanning (transmission) electron microscopy. When increasing the calcination temperature (from 250 to 700 and 850 degrees C), NiO particles from synthesis (I) grow larger and experience a removal of intra-bandgap states upon more complete formation to NiO. NiO NPs from synthesis (II) present a defined electronic structure with low defect density within the TA ranges probed, whereas an annealing step introduces delocalized defects. During electrocatalytic measurements (KOH or KOH + urea electrolyte), we distinguished surface area effects by morphology from intrinsic catalytic activities governed by defect states and correlated less defective materials with higher intrinsic activities, as well as lower charge transfer resistances. This work advances material characterization by a holistic combination of a comparably rare optoelectronic spectroscopic strategy with electrochemical characterization to understand fundamental material properties and their influence on catalytic performance, demonstrating niche investigation strategies of NiO in UOR catalysis.

Monolithic perovskite–organic tandem solar cells (P–O TSCs) establish a mutual protection system, which enables high-efficiency P–O TSCs (25.12%) to achieve exceptional operational stability, retaining over 91% after 1000-hour illumination.

The ALD precursor tetrakis(dimethylamido)tin and water are exploited towards the atomic-layer additive manufacturing (ALAM) of SnO2 lines. ALAM exploits the surface chemistry principles of ALD (atomic layer depositions) but adds a laterally constrained precursor delivery. Motion of the precursor delivery nozzle over the substrate surface thus deposits the material in a 3D printing mode while maintaining the sub-nanometers thickness control of ALD. We find that the precursor canister temperature can be lowered by approximately 20 degrees C from ALD to ALAM, corresponding to a lower precursor consumption. The temperature window of controlled deposition reaches from 150 degrees C to 250 degrees C, whereas 200 degrees C yields the best stoichiometry and highest growth rate. The material is amorphous initially and crystallizes upon annealing at 500 degrees C in N2 or air. The lines deposited have a flat top profile and a constant thickness along their length.

Atomare Kontrolle über lösungsprozessierte hybride Halogenid‐Perowskite wird experimentell durch Atomlagenabscheidung aus der Lösung (Engl. solution atomic layer deposition , sALD) erreicht. Diese Methode überträgt die oberflächenchemischen Prinzipien der Gasphasen‐ALD (gALD) auf in der Flüssigphase gelöste Präkursoren. Durch das Umgehen der Einschränkungen, die mit der für die gALD nötige Flüchtigkeit der Präkursoren verbunden sind, erweitert die sALD das Spektrum nutzbarer Reaktions‐Chemien und zugänglicher Materialklassen. Wir demonstrieren ihre Anwendbarkeit für die Abscheidung ultradünner Filme ionischer Halbleiter, indem wir ein sALD‐Verfahren für den prominentesten Halogenid‐Perowskit, Methylammonium‐Triiodidoplumbat (CH 3 NH 3 PbI 3 , „MAPI“) entwickeln. Der Prozess zeigt bei Variation der Präkursordosierung ein sättigendes, selbstlimitierendes Wachstum, wie es für ALD typisch ist, was sowohl ex‐situ als auch in‐situ nachgewiesen wird. Die durch sALD abgeschiedenen MAPI‐Filme sind hochrein, stöchiometrisch und polykristallin. Werden MAPI‐Filme paarweise und in jeweils identischer Dicke durch sALD und durch ein modernes Spin‐Coating‐Verfahren hergestellt, so übertreffen die sALD‐Filme ihre Spin‐Coating Gegenstücke deutlich hinsichtlich der Ladungsträgerlebensdauer und der Stabilität. Sie weisen zudem eine hohe Ladungsträgermobilität auf und bilden funktionale lichtabsorbierende Schichten in Solarzellen.

Antimony sulfide (Sb2S3), a compound of earth-abundant elements with a highly anisotropic, quasi-layered crystal structure, has triggered growing interest as a solar absorber in photovoltaics and as a phase-change material in memory devices. However, challenges remain in achieving high-quality thin films with controlled nucleation and growth for optimal performance. Here, we investigate the phase transformation, crystal structure and properties, as well as the growth and degradation of atomic layer-deposited Sb2S3 thin films using in situ TEM and correlative ex situ analysis. The as-deposited amorphous films crystallized at 243 °C, forming grains with an [100] out-of-plane texture that developed into tens to hundreds of micrometer-long, leaf-shaped grains. Introducing an ultrathin ZnS interfacial layer increased nucleation density, resulting in few-micrometer-sized, more uniform grains while retaining the overall [100] texture. In situ observations and subsequent crystal orientation analysis with cutting-edge 4D-STEM and EBSD revealed that the grains grew faster along the [010] ribbon direction and that the bare films underwent early-stage degradation, forming holes in amorphous regions during annealing. The ZnS interlayer mitigated degradation, stabilizing the films and improving their uniformity. These findings offer valuable insights for optimizing Sb2S3 thin films for applications as both solar cell materials and phase-change materials.

Charge transfer and recombination dynamics are key to understanding and optimizing photovoltaic devices. However, metallic contacts are typically used to fabricate devices, making them incompatible with transmission spectroscopic techniques such as transient absorption spectroscopy (TAS). Omission of the top contact to avoid this issue results in mismatched results and has limited previous work examining the dynamics in thin-film Sb2S3-based devices. In this work, this challenge is overcome by developing a new methodology, adding a protective layer of ZnO over hole transport materials, allowing fabrication of transparent (i.e., bifacial) solar cell devices. Photovoltaic characterization reveals similar J-V curves between reference and bifacial cells. Examination with TAS reveals a modified mechanism that builds off of previously proposed models for similar systems. Optical modeling supports the understanding of several important changes to the mechanism. These results provide a path toward the investigation of photo-driven dynamics under more realistic operating conditions.

Visible-light responsive, stable, and abundant absorbers are required for the rapid integration of green, clean, and renewable technologies in a circular economy. Photoactive solid-solid heterojunctions enable multiple charge pathways, inhibiting recombination through efficient charge transfer across the interface. This study spotlights the physico-chemical synergy between titanium dioxide (TiO2) anatase and carbon nitride (CN) to form a hybrid material. The CN(10%)-TiO2(90%) hybrid outperforms TiO2 and CN references and literature homologs in four photo and photoelectrocatalytic reactions. CN-TiO2 achieved a four-fold increase in benzylamine conversion, with photooxidation conversion rates of 51, 97, and 100 % at 625, 535, and 465 nm, respectively. The associated energy transfer mechanism was elucidated. In photoelectrochemistry, CN-TiO2 exhibited 23 % photoactivity of the full-spectrum measurement when using a 410 nm filter. Our findings demonstrate that CN-TiO2 displayed a band gap of 2.9 eV, evidencing TiO2 photosensitization attributed to enhanced charge transfer at the heterointerface boundaries via staggered heterojunction type II.

The conversion of metal-nitrogen-carbon (M-N-C) nanoparticles derived from conventional metal-organic frameworks (MOFs) into self-supporting and well-defined metal-nitrogen-carbon (M-N-C) superstructures is essential for various functional applications but remains a significant challenge. In this study, a versatile chemical vapor deposition (CVD) strategy is developed for solvent-free synthesis of self-supporting carbonaceous nanotubes doped with metal and nitrogen (MNCT). The stable carbonaceous nanotubes doped with Fe and N (FeNCT) fabricated here exhibit excellent electrocatalytic performances for the oxygen evolution reaction (OER) and outperform the carbonaceous film doped with Fe and N grown on carbon foil directly (FeNC/CF), which demonstrates the advantages of the superstructure of FeNCT. This strategy also provides a way to tailor the metal-nitrogen-carbon nanotubes (MNCT) catalyst according to the feature of the reactor and exhibits many advantages, such as wide applicability and facile scalability.

Hydrogen (H 2 ) is increasingly recognized as a crucial energy carrier, and its production via water electrolysis powered by CO 2 -free energy is emerging as a viable large-scale solution. H 2 and O 2 production from H 2 O photoelectrolysis exhibits a similar theoretical efficiency compared to photovoltaics/electrolysis coupling around 35% [1]. It is, however, a straightforward process which involves the direct splitting of water in a photoelectrochemical cell (PEC) under sunlight and heat will improve the kinetics reaction while photovoltaics’ yield suffers from temperature increase. A recent breakthrough achieved an impressive 19% conversion efficiency [2] using an unbiased PEC constructed with high-cost and unstable III-V semiconductors combined with platinum-group catalysts. Despite this progress, H 2 production costs remain higher than those of fossil fuel-derived H 2, highlighting the need for improvements in efficiency, stability, and cost-effectiveness. As photoelectrodes are at the core of these devices, they are the focus of research efforts in three main directions: (i) surface structuring to improve light absorption and increase active surface area, (ii) the deposition of co-catalysts to accelerate reaction kinetics and boost photocurrent and, (iii) protective coatings that extend electrode durability. In recent years, atomic layer deposition (ALD) has demonstrated significant potential to address part of these challenges. ALD’s ability to uniformly coat nanostructured surfaces with either continuous, pinhole-free films or evenly distributed nanoparticles makes it particularly well-suited for these applications. This work starts with a brief overview of water photosplitting, including its principles, key materials, and current challenges. It then explores the role of ALD in advancing this field. We will show our recent works in protecting Si photoelectrodes including the limitations and the corrosion processes that have been elucidated [3] but also on how combining materials (absorbers and co-catalysts) can lead to better PEC efficiency. A special attention will be drawn on the relation between the film deposition conditions and their physico-chemical properties and more importantly their functional properties. [1] S. Keene, R. Bala Chandran, S. Ardo, Energy Environ. Sci. 12 , 261(2019) [2] W.-H. Cheng et al, ACS Energy Lett. 3 , 1795 (2018) [3] M. E. Dufond, J.-N. Chazalviel, L. Santinacci, J. Electrochem. Soc. 168 , 031509 (2021)

This document is the unedited not peer-reviewed Author’s version of a Submitted Work to Chemistry of Materials. The controlled assembly of supraparticles using spray-drying enables the synthesis of nanoporous materials. Changing the size of the constituent nanoparticles or their agglomeration states provides access to a diverse range of pore frameworks. This turns supraparticles into ideal scaffolds in heterogeneous catalysis. The combination of supraparticles with atomic layer deposition (ALD) as a surface functionalization technique offers excellent control over the deposition of a functional material and its distribution over the scaffold on the nanoscale. This work reports the combination of SiO2 supraparticles as tunable scaffolds and their loading with a platinum-based ALD catalyst. The deliberate adjustment of the scaffold pore framework via spray-drying and its effects on the catalyst deposition are highlighted. Furthermore, varying numbers of Pt ALD cycles are applied to explore the capability of the combinational approach with respect to catalyst loading and Pt efficiency. High-resolution electron microscopy reveals ultra-small Pt clusters deposited on the supraparticles after the very first ALD cycle. Using the hydrogenation of 4-nitrophenol as a demonstration, the impact of the pore framework and the Pt deposition variation in ALD on the catalytic functionality is investigated.