Environment-Induced Reversible Modulation of Optical and Electronic Properties of Lead Halide Perovskites and Possible Applications to Sensor Development: A Review

none4siLead halide perovskites are currently widely investigated as active materials in photonic and optoelectronic devices. While the lack of long term stability actually limits their application to commercial devices, several experiments demonstrated that beyond the irreversible variation of the material properties due to degradation, several possibilities exist to reversibly modulate the perovskite characteristics by acting on the environmental conditions. These results clear the way to possible applications of lead halide perovskites to resistive and optical sensors. In this review we will describe the current state of the art of the comprehension of the environmental effects on the optical and electronic properties of lead halide perovskites, and of the exploitation of these results for the development of perovskite-based sensors.openDe Giorgi, ML; Milanese, S; Klini, A; Anni, MDe Giorgi, Ml; Milanese, S; Klini, A; Anni,

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Analysis of the demand, of the use of the IDRIN and of new potential developments

Low Energy Pulsed Laser Excitation in UV Enhances the Gas Sensing Capacity of Photoluminescent ZnO Nanohybrids

Nanohybrids, composed of luminescent zinc oxide (ZnO) nanoparticles dispersed in an inert polydimethylsiloxane (PDMS) matrix, exhibit an excellent ability to follow changes in the type and composition of their surrounding atmosphere. These changes are found to affect the UV photoluminescence (PL) emission of the ZnO-PDMS hybrids measured at room temperature. The influence of irradiation parameters, such as excitation intensity and wavelength, on the response of the ZnO-PDMS sensor against ethanol and oxygen, have been systematically investigated in a comparative study performed employing pulsed excitation at 248 and 355 nm. This study represents the first demonstration that the sensing performance of the PL-based ZnO sensors can be optimized by tuning the excitation parameters and it particularly illustrates that maintaining a low pump energy density is crucial for enhancing the sensitivity of the sensor achieving response values approaching 100%

Sub-ps Pulsed Laser Deposition of Boron Films for Neutron Detector Applications

In view of the demand for high-quality thermal neutron detectors, boron films have recently attracted widespread research interest because of their special properties. In this work, we report on the deposition of boron films on silicon substrates by sub-picosecond pulsed laser deposition (PLD) at room temperature. Particular emphasis was placed on the investigation of the effect of the laser energy density (fluence) on the ablation process of the target material, as well as on the morphological properties of the resulting films. In addition, based on the study of the ablation and deposition rates as a function of the fluence, the ablation/deposition mechanisms are discussed. We show that well-adherent and stable boron films, with good quality surfaces revealing a good surface flatness and absence of cracks, can be obtained by means of the PLD technique, which proves to be a reliable and reproducible method for the fabrication of thick boron coatings that are suitable for neutron detection technology

Tuning spectral properties of ultrafast laser ablation plasmas from brass using adaptive temporal pulse shaping

International audienceUsing automated laser pulse temporal shaping we report on enhancing spectral emission characteristics of ablation plasmas produced by laser irradiation of brass on ultrafast time scales. For different input irradiance levels, control of both atomic and ionic species becomes possible concerning the yield and the excitation state. The improved energy coupling determined by tailored pulses induces material ejection with lower mechanical load that translates into hot gas-phase regions with higher excitation degrees and reduced particulates

Electrodeposition of Ni particles on laser nanostructured electrodes for enhanced hydrogen evolution reaction

Part of special issue: International Conferences & Exhibition on Nanotechnologies, Organic Electronics & Nanomedicine – NANOTEXNOLOGY 2021.The authors would like to acknowledge the HELLAS-CH national infrastructure (MIS 5002735) implemented under “Action for Strengthening Research and Innovation Infrastructures,” funded by the Operational Program” Competitiveness, Entrepreneurship and Innovation” (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund).Περίληψη: In this study, a two-step electrode fabrication process is used to enlarge the electrocatalytic area of the electrodes and improve the hydrogen evolution reaction. Nickel electrodes were laser-nanostructured, and afterward, they were galvanostatically electrodeposited, a novel approach for electrodes used for HER. SEM and EDX analysis were performed. The electrochemical evaluation provided enhanced values of overpotential (η10 = 108 mV), Tafel slope (b = −121 mV dec−1) and double layer capacitance (1945 μF cm−2) compared to the literature. The stability of the electrodes was tested by its overpotential (|η100|=264 mV) in a current density of 100 mA cm−2.Παρουσιάστηκε στο: Materials Today: Proceeding

Electrodeposited laser – nanostructured electrodes for increased hydrogen production

PL, MF, AK, NP acknowledge financial support from the European Union’s Horizon 2020 research and innovation program under grant agreement no 871124 Laserlab-Europe. The authors would like to acknowledge the HELLAS-CH national infrastructure (MIS 5002735) implemented under “Action for Strengthening Research and Innovation Infrastructures,” funded by the “Operational Programme Competitiveness, Entrepreneurship and Innovation” (NSRF 2014–2020) and co-financed by Greece and the European Union (European Regional Development Fund).Περίληψη: In the present work, a novel approach has been employed to effectively enlarge the electrocatalytic area of the electrodes in an alkaline electrolysis setup. This approach consists of a two-step electrode fabrication process: In the first step, ultrashort laser pulses have been used to nanostructure the electrode surface. In the second step, electrodeposition of nickel particles was performed in a modified Watt's bath. The resulting electrodes have been found to exhibit a significantly increased hydrogen evolution reaction (HER) activity. Compared to the laser-nanostructured electrode (LN) and an untreated (i.e., flat) electrode, the electrodeposited-laser-nanostructured (ELN) electrode provides (i) enhanced electrochemical values (ii) a significant increase of double-layer capacitance (CDL) (values up to 1945 μF cm−2) compared to that of an LN electrode (288 μF cm−2) (iii) higher Jpeaks at CVs sweeps and (iv) lower Tafel slopes (−121 mV dec−1 compared to −157 mv dec−1). The ELN electrode provides an overpotential value of |η|100 = 264 mV, which shows a noteworthy 34% decrease compared to a flat Ni electrode and a 15% decrease to an (LN) electrode. Scanning electron microscopy (SEM) revealed that the electrodeposition of nickel on the LN nickel electrodes results in a dendrite-like morphology of the surface. Thus, the enhancement of the HER has been attributed to the dendrite-like geometry and the concomitant enlargement of the electrocatalytic area of the electrode, which presents an electrochemical active surface area (ECSA) = 97 cm−2 compared to 2.8 cm−2 of the flat electrode. The electrodes have also been tested in actual hydrogen production condition, and it was found that the ELN electrode produces 4.5 times more hydrogen gas than a flat Ni electrode and 20% more hydrogen gas than an LN electrode (i.e. without the extra nickel electrodeposition).Presented on: International Journal of Hydrogen Energ