Francesco De Boni

Lead-free chalcohalides are promising semiconductors, combining chalcogenide stability with mixed-anion versatility and low toxicity. Among them, CuBiSCl2 is attractive due to its quasi-direct band gap and strong near-infrared absorption. However, its synthesis has been limited to high-temperature solid-state methods, hindering thin film processing. Here, we report the first low-temperature (150 °C) colloidal hot-injection synthesis of phase-pure CuBiSCl2 submicron crystals with a platelet-like morphology and demonstrate their integration into solution-processed thin films and planar photoconductive devices. Spin-coated films are compact and uniform, exhibiting a band gap of ∼1.49 eV. The materials are stable under controlled conditions but undergo irreversible phase evolution upon exposure to air and heating. A proof-of-concept device made with CuBiSCl2 exhibits a photoresponse under 590 nm illumination, with a spectral responsivity of 5 × 10–6 A/W under an applied bias of 2 V and a photocurrent of ∼100 nA. This result establishes CuBiSCl2 as a promising material for optoelectronic and photovoltaic applications.

Light-emitting diodes (LEDs) based on colloidal InAs quantum dots (QDs) have emerged as promising light sources for the short-wave infrared (SWIR) range. However, their development is limited by relatively low photoluminescence quantum yield as well as intrinsic device design challenges. Here, we report LEDs with electroluminescence (EL) in the SWIR based on InAs/ZnSe core/shell colloidal QDs, synthesized via a seedless one-pot approach that enables the rapid growth of relatively large InAs cores. Zirconium-doped indium oxide (InZrO) was used as the bottom transparent electrode owing to its significantly higher infrared transparency compared to the commonly employed tin-doped indium oxide (ITO). These two key innovations pushed the EL beyond 1500 nm, with external quantum efficiencies of 3.0, 1.2, and 0.6% at 1093, 1198, and 1547 nm, respectively.

This article presents a correlative analytical strategy for studying nanoparticle–microbe interactions. Understanding the intracellular transformations of metallic nanoparticles (MNPs) provides critical insights into their antimicrobial mechanisms and informs the design of safe, durable antimicrobial materials. Conventional analytical techniques, however, are limited in their ability to simultaneously capture nanoscale morphological changes and the chemical‐state evolution of nanoparticles within microbial cells. To address this, a strategy integrating high‐resolution scanning electron microscopy (HR‐SEM) with sputtering‐enabled intracellular x‐ray photoelectron spectroscopy (SEI‐XPS) was developed, enabling depth‐resolved, chemically specific analysis of nanoparticle–microbe interactions. Using AgNPs and PtNPs as model systems, their fate was investigated in one bacterium ( Arthrobacter sp.) and two phylogenetically distinct fungi (Alternaria obovoidea and Cladosporium sp.). SEM revealed rapid membrane disruption in bacteria and slower, species‐dependent structural impairment in fungi. SEI‐XPS demonstrated biologically induced oxidation of AgNPs, with increasing Ag(I) and higher‐order oxidized species correlating with exposure time and microbial damage, while PtNPs remained predominantly metallic, confirming an ion‐release‐independent antimicrobial mechanism. Depth profiling enabled direct chemical‐state mapping of intracellular nanoparticle residues, revealing persistent metallic cores for both AgNPs and PtNPs. This approach provides mechanistic insight inaccessible through conventional assays and establishes SEI‐XPS as powerful, laboratory‐based method for probing nanoparticle transformations in living microbial systems. The methodology also offers a framework for rational design of next‐generation antimicrobial coatings, including those intended for cultural heritage conservation.

Glycerol electrooxidation (GEOR) is a compelling alternative to the oxygen evolution reaction (OER) in water electrolysis, lowering energy demand while simultaneously producing valuable chemicals. However, efficient and selective catalysts for GEOR remain limited, and a significant gap exists between laboratory research and industrial application. In this study, Ni-based chalcogenides and pnictogenides (NiXy, X = O, S, P, Se) were synthesized to investigate the role of heteroatoms in active-site formation and GEOR selectivity. Among the materials studied, NiSe2 exhibited the best GEOR activity, delivering 100 mA cm–2 at 1.45 VRHE while achieving ≈100% Faradaic efficiency (FEGEOR), with 95% selectivity toward formate. In situ spectroscopy, diffraction analysis, and first-principles calculations reveal that this improved performance originates from rapid γ-NiOOH formation and optimized glycerol adsorption energy. This work reports a dry-cathode zero-gap GEOR-HER electrolyzer successfully operating under industrially relevant conditions (i.e., 400 mA cm–2 at 60 °C), achieving nearly unity FEGEOR at 1.7 V with complete suppression of OER, highlighting GEOR-HER potential to enhance both energy efficiency and economic viability of electrolytic hydrogen production.

Theoretical steps of the oxygen evolution reaction (OER), alongside optical microscopy images of the samples as a function of manganese doping. A colour transition from yellow, through green, to blue is observed as the manganese content increases.

We report the synthesis and optoelectronic characterization of a two-dimensional layered halide perovskite (2DLP), TPA2PbBr4, incorporating tryptammonium (TPA) as a π-conjugated organic spacer molecule. TPA-Br, derived from indole-containing tryptamine, enables CH-π and NH-π interactions, enhancing structural rigidity and electronic coupling with the layered framework. TPA2PbBr4 microcrystals grown via a slow vapor diffusion method exhibit a highly oriented Ruddlesden–Popper-type structure, confirmed by powder and single-crystal X-ray diffraction (XRD) analyses. In situ temperature-dependent XRD confirms high thermal stability without phase transition from 183 to 433 K. Optical measurements reveal a sharp excitonic absorption peak near 398 nm and a narrow photoluminescence peak at 407 nm. Uniform spin-coated thin films display an excitonic double peak and pronounced Fabry–Pérot microcavity modes in their reflectance spectra, indicating strong optical confinement. The Fabry–Pérot microcavity sustained by the TPA2PbBr4 thin films facilitates such strong light-matter coupling, manifested by the formation of polariton modes. Planar photodetectors (PDs) with TPA2PbBr4 films exhibit stable ultraviolet photoresponse, low dark current, responsivity (R) of 1 mA/W, and detectivity (D*) of 2.2 × 1010 Jones. Vertically configured PDs based on TPA2PbBr4 thin films exploit their built-in electric field, enabling self-powered operation. The combination of strong excitonic features, microcavity-enhanced light absorption, and self-biased device operation highlights TPA2PbBr4 as a promising material for UV-selective PDs and low-power optoelectronic applications, benefiting from its strong excitonic features and π-conjugated organic spacer chemistry.

Indium arsenide (InAs) gas sensors are conventionally fabricated using epitaxial methods, which rely on costly equipment and are less suitable for low-cost manufacturing; therefore, the number of studies on InAs-based gas sensors has remained limited. In this paper, we report the gas-sensing properties of colloidal InAs quantum dots (QDs) and InAs-ZnSe core-shell QDs synthesized via a cost-effective and scalable hot-injection chemical route. This approach presents significant advancements and offers a practical and accessible alternative to epitaxial methods. The growth of the ZnSe shell over InAs enhances the chemical stability of QDs and improves their sensing response. Our findings demonstrate that colloidal InAs QD-based sensors show a response of 2.97 to 50 ppm H₂S gas, which remarkably enhanced to 26 under the same conditions after growing the ZnSe shell and the formation of InAs-ZnSe core-shell QDs. These findings establish the feasibility and effectiveness of colloidal III-V QDs for gas-sensing applications, offering a new low-cost pathway for developing sensors based on III-V semiconductors.

Short-wave infrared (SWIR) optoelectronics based on colloidal quantum dots (QDs) have been dominated by heavy-metal chalcogenides for many years (e.g., PbS, HgTe). Here, we present Restriction of Hazardous Substances-compliant InAs/ZnSe core/shell QD light-emitting diodes (LEDs) operating in the SWIR spectral range. The InAs cores are synthesized via a tris­(dimethylamino)­arsine-based continuous-injection method, enabling size control and SWIR spectral tuning. The LEDs employ a hybrid charge-injection stack comprising organic hole-transport layers (poly-TPD/PTAA) and an inorganic ZnMgO electron-transport layer to balance injection into the InAs/ZnSe core/shell QD film. Four different LEDs, with electroluminescence (EL) peaks centered at 1007, 1275, 1300, and 1410 nm, achieve external peak quantum efficiencies of 6.20%, 3.75%, 2.04%, and 1.10%, respectively. This work is the first demonstration of EL from InAs QDs beyond 1100 nm, advancing III–V QDs for SWIR optoelectronic systems in fields such as machine vision and bioimaging.