Scalable Production of Metal Oxide Nanoparticles for Optoelectronics Applications.

This work describes the scalability process of a continuous-injection protocol employed to produce tin-doped indium oxide nanocrystal dispersions. Different levels of manipulation starting from the synthesis and processing also related to the tuning of the optical response (considering the peculiar combination of UV and NIR absorption with visible transparency) make these materials incredibly versatile. But one of the most attractive features concern the modulation of their charge carrier density through chemical or post-synthetic doping, as for the case of core-shell materials, expanding the properties of the core composition.

Development of an automated SILAR method for the sustainable fabrication of BiOI/TiO photoanodes.

BiOI is a promising material for use in photoelectrocatalytic water oxidation, renowned for its chemical inertness and safety in aqueous media. For device integration, BiOI must be fabricated into films. Considering future industrial applications, automated production is essential.

Two-Dimensional Layered Heterojunctions for Photoelectrocatalysis.

Two-dimensional (2D) layered nanomaterial heterostructures, arising from the combination of 2D materials with other low-dimensional species, feature a large surface area to volume ratio, which provides a high density of active sites for catalytic applications and for (photo)electrocatalysis (PEC). Meanwhile, their electronic band structure and high electrical conductivity enable efficient charge transfer (CT) between the active material and the substrate, which is essential for catalytic activity. In recent years, researchers have demonstrated the potential of a range of 2D material interfaces, such as graphene, graphitic carbon nitride (g-CN), metal chalcogenides (MCs), and MXenes, for (photo)electrocatalytic applications.

2D MoS/BiOBr van der Waals heterojunctions by liquid-phase exfoliation as photoelectrocatalysts for hydrogen evolution.

As a semiconductor used for the photocatalytic hydrogen evolution reaction (HER), BiOBr has received intensive attention in recent years. However, the high recombination of photoexcited charge carriers results in poor photocatalytic efficiency. The combination with other photoactive semiconductors might represent a valuable approach to deal with the intrinsic limitations of the material.

High Open-Circuit Voltage Cs AgBiBr Carbon-Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray-Coated Carbon Electrodes from Waste Tire Sources.

Invited for this month cover is the group of Teresa Gatti at the Justus Liebig University (JLU) in Giessen, Germany, the group of Federico Bella at Politecnico di Torino (POLITO), Italy, and the group of Francesco Lamberti at the University of Padova (UNIPD), also in Italy. The image shows how waste tires can be converted in a conductive carbon powder that undergoes a green processing step to produce carbon electrodes for lead-free perovskite solar cells. Similar devices can be employed to harvest indoor light in order to power the Internet of Things (IoT) ecosystem.

Nanostructured 2D WS@PANI nanohybrids for electrochemical energy storage.

2D materials are interesting flat nanoplatforms for the implementation of different electrochemical processes, due to the high surface area and tunable electronic properties. 2D transition metal dichalcogenides (TMDs) can be produced through convenient top-down liquid-phase exfoliation (LPE) methods and present capacitive behaviour that can be exploited for energy storage applications. However, in their thermodynamically stable 2H crystalline phase, they present poor electrical conductivity, being this phase a purely semiconducting one.

High Open-Circuit Voltage Cs AgBiBr Carbon-Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray-Coated Carbon Electrodes from Waste Tire Sources.

Costs and toxicity concerns are at the center of a heated debate regarding the implementation of perovskite solar cells (PSCs) into commercial products. The first bottleneck could be overcome by eliminating the top metal electrode (generally gold) and the underlying hole transporting material and substituting both with one single thick layer of conductive carbon, as in the so-called carbon-based PSCs (C-PSCs). The second issue, related to the presence of lead, can be tackled by resorting to other perovskite structures based on less toxic metallic components.

Deciphering Photoinduced Charge Transfer Dynamics in a Cross-Linked Graphene-Dye Nanohybrid.

The search for synthetic materials that mimic natural photosynthesis by converting solar energy into other more useful forms of energy is an ever-growing research endeavor. Graphene-based materials, with their exceptional electronic and optical properties, are exemplary candidates for high-efficiency solar energy harvesting devices. High photoactivity can be conveniently achieved by functionalizing graphene with small molecule organic semiconductors whose band-gaps can be tuned by structural modification, leading to interactions between the π-conjugated electronic systems in both the semiconductor and graphene.

Tuning the optical properties of 2D monolayer silver-bismuth bromide double perovskite by halide substitution.

Silver-bismuth double perovskites are promising replacement materials for lead-based ones in photovoltaic (PV) devices due to the lower toxicity and enhanced stability to environmental factors. In addition, they might even be more suitable for indoor PV, due to the size of their bandgap better matching white LEDs emission. Unfortunately, their optoelectronic performance does not reach that of the lead-based counterparts, because of the indirect nature of the band gap and the high exciton binding energy.

Lanthanide-Induced Photoluminescence in Lead-Free CsAgBiBr Bulk Perovskite: Insights from Optical and Theoretical Investigations.

Emphasis was recently placed on the CsAgBiBr double perovskite as a possible candidate to substitute toxic lead in metal halide perovskites. However, its poor light-emissive features currently make it unsuitable for solid-state lighting. Lanthanide doping is an established strategy to implement luminescence in poorly emissive materials, with the additional advantage of fine-tuning the emission wavelength.

Self-Powered and Broadband Lead-Free Inorganic Perovskite Photodetector with High Stability.

Metal halide perovskite materials have opened up a great opportunity for high-performance optoelectronic devices owing to their extraordinary optoelectronic properties. More than lead halide ones, stable and nontoxic bismuth halide perovskites exhibit more promise in their future commercialization. In this work, we developed for the first time photodetectors based on full-inorganic CsBiIBr perovskites and modulate their performance by varying in the composition systematically.

Physico-Chemical, Electrochemical and Structural Insights Into Poly(3,4-ethylenedioxythiophene) Grafted from Molecularly Engineered Multi-Walled Carbon Nanotube Surfaces.

Composites of multi-walled carbon nanotubes (MWCNTs) and poly(3,4-ethylenedioxythiophene) (PEDOT) are attracting the attention of material scientists since more than a decade as potential next-generation optoelectronic materials for their peculiar features, arising from the combination of the intrinsic electrical, thermal and morphological properties of the two components. They are indeed a promising platform for the development of low-cost, portable and environmentally friendly electronic devices such as supercapacitors, sensors and actuators. Here a novel synthetic strategy for their preparation is envisaged, exploiting the possibility to covalently functionalize the external surface of MWCNTs with tailored molecular units, starting from which the growth of the conjugated polymer can be induced oxidatively.

Probing photoinduced electron-transfer in graphene-dye hybrid materials for DSSC.

We investigated the photophysical properties of a newly synthesized hybrid material composed of a triphenylamine dye covalently bound to reduced graphene oxide, potentially relevant as a stable photosensitizer in dye-sensitized solar cells. The photophysical characterization has been carried out by means of fluorescence quenching and fluorescence lifetime measurements, complemented by Electron Paramagnetic Resonance (EPR) spectroscopy, aimed at the detailed description of the photoinduced processes occurring in the hybrid and in the mixed hybrid/N-doped TiO material. The combined optical/magnetic study unequivocally demonstrates a fast quenching of the dye excited state in the isolated hybrid and an efficient electron transfer to N-doped titania nanopowders.

Neuronal commitment of human circulating multipotent cells by carbon nanotube-polymer scaffolds and biomimetic peptides.

Aim: We aimed to set up a self-standing, biomimetic scaffold system able to induce and support per se neuronal differentiation of autologous multipotent cells.

Materials & Methods: We isolated a population of human circulating multipotent cells (hCMCs), and used carbon nanotube/polymer nanocomposite scaffolds to mimic electrical/nanotopographical features of the neural environment, and biomimetic peptides reproducing axon guidance cues from neural proteins.

Results: hCMCs showed high degree of stemness and multidifferentiative potential; stimuli from the scaffolds and biomimetic peptides could induce and boost hCMC differentiation toward neuronal lineage despite the absence of exogenously added, specific growth factors.

Structure-Photoluminescence Correlation for Two Crystalline Polymorphs of a Thiophene-Phenylene Co-Oligomer with Bulky Terminal Substituents.

Two crystal polymorphs of a thiophene-phenylene hexamer with bulky terminal substituents are characterized by different molecular conformations and parallel versus herringbone packing. Irrespective of their similar emissive spectra and common H-aggregate features, evidenced by crystal structure analysis and confirmed by solid-phase and excited-state first-principles calculations, their luminescence is relatively high and, for one form, nearly double than that for the other. Interaromatic packing energy contributions are established by quantum chemical calculations and can be compared quantitatively as the same species in different crystal environments is examined.

Improving the efficiency of the photoinduced charge-separation process in a rhenium(I)-zinc porphyrin dyad by simple chemical functionalization.

We demonstrate here that, whereas the rhenium(I)-zinc porphyrin dyad fac-[Re(CO)3(bpy)(Zn·4'MPyP)](CF3SO3) [1; 4'MPyP = 5-(4'-pyridyl)-10,15,20-triphenylporphyrin] shows no evidence for photoinduced electron transfer upon excitation in the visible region because the charge-separated state ZnP(+)-Re(-) is almost isoenergetic with the singlet excited state of the zinc porphyrin (ΔG = -0.05 eV), the introduction of electron-withdrawing ethyl ester groups on the bpy ligand significantly improves the thermodynamics of the process (ΔG = -0.42 eV).

Concerted motions in supramolecular systems: metal-mediated assemblies of porphyrins that behave like nanometric step-machines.

According to NMR evidence the metal-mediated sandwich assemblies of porphyrins 2 and 3 undergo in solution a thermally driven motion that resembles that of a stepper: the spontaneous rotational motion of the pyridyl rings is converted into a reciprocating linear motion of the porphyrins.