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Showing papers by "Vittorio Scardaci published in 2020"


Journal ArticleDOI
TL;DR: Biomedicine, catalysis and sensing are the application areas mainly discussed in this review, highlighting advantages of laser-synthesized nanoparticles for these types of applications and, once partially resolved, the limitations to the technique for large-scale applications.
Abstract: Laser synthesis emerges as a suitable technique to produce ligand-free nanoparticles, alloys and functionalized nanomaterials for catalysis, imaging, biomedicine, energy and environmental applications. In the last decade, laser ablation and nanoparticle generation in liquids has proven to be a unique and efficient technique to generate, excite, fragment and conjugate a large variety of nanostructures in a scalable and clean way. In this work, we give an overview on the fundamentals of pulsed laser synthesis of nanocolloids and new information about its scalability towards selected applications. Biomedicine, catalysis and sensing are the application areas mainly discussed in this review, highlighting advantages of laser-synthesized nanoparticles for these types of applications and, once partially resolved, the limitations to the technique for large-scale applications.

104 citations


Journal ArticleDOI
TL;DR: In this article, a review of various solution-processed methods for the preparation of different 2D materials is presented, and the applications and performance of solution-processing-based materials in fiber lasers are discussed.
Abstract: Abstract Since graphene was first reported as a saturable absorber to achieve ultrafast pulses in fiber lasers, many other two-dimensional (2D) materials, such as topological insulators, transition metal dichalcogenides, black phosphorus, and MXenes, have been widely investigated in fiber lasers due to their broadband operation, ultrafast recovery time, and controllable modulation depth. Recently, solution-processing methods for the fabrication of 2D materials have attracted considerable interest due to their advantages of low cost, easy fabrication, and scalability. Here, we review the various solution-processed methods for the preparation of different 2D materials. Then, the applications and performance of solution-processing-based 2D materials in fiber lasers are discussed. Finally, a perspective of the solution-processed methods and 2D material-based saturable absorbers are presented.

39 citations


Journal ArticleDOI
TL;DR: In this article, a self-started stable Q-switched Yb-doped all-fiber laser based on a solution-processed Ag nanoplates saturable absorber is reported.
Abstract: Abstract We report on a Q-switched Yb-doped all-fiber laser based on a solution-processed Ag nanoplates saturable absorber. Optical deposition procedure is implemented to transfer the Ag nanoplates onto the fiber core area through the thermal effect. The saturable absorber is sandwiched between two fiber connectors, providing simplicity, flexibility, and easy integration into the laser oscillator. The modulation depth and saturation incident fluence are measured to be ~5.8% and ~106.36 μJ/cm2 at 1-μm region, respectively. Self-started stable Q-switched operation is achieved for a threshold pump power of 180 mW. The repetition rates of the pulse trains range from 66.6 to 184.8 kHz when the pump power scales from 210 to 600 mW. The maximum average output power is 10.77 mW, corresponding to the single-pulse energy of 58.3 nJ and minimum pulse duration of ~1.01 μs. To the best of our knowledge, it is the first time that the Ag nanoplates saturable absorbers are utilized in the 1-μm Yb-doped Q-switched fiber laser.

22 citations


Journal ArticleDOI
TL;DR: In this paper, the formation of flat silver nanoparticle colloids through the use of pulsed laser beams and monochromatic LEDs was demonstrated by using monochrome LEDs and H2O2 under the irradiation of light.
Abstract: The size and shape of metal nanoparticles play a key role in most of their technological applications because they determine their optical properties in the UV-vis-NIR range as well as their interaction with molecules in the surroundings. In this paper, we demonstrate the “in liquid” formation of flat silver nanoparticle colloids through the use of pulsed laser beams and monochromatic LEDs. The transformation of spherical to flat nanoparticles is driven and sustained by the addition of H2O2 and citrate under the irradiation of light. In this respect, it is demonstrated that high citrate concentrations limit the growth of some crystalline facets, yielding smaller plates with the plasmon resonance of the final colloid confined to the visible region, while the use of lower concentrations results in the formation of large plates with resonances in the near infrared region. Thus, the manipulation of citrate concentration in the solution and the choice of the irradiation wavelength give rise to the possibility to tune the position of the main plasmon resonance across the visible and near IR part of the spectrum. Plasmon sensitivity measurements show that nanoplates irradiated at the longest wavelength showed the highest response to a refractive index change.

10 citations


Journal ArticleDOI
TL;DR: In this paper, a CW laser beam was employed to study the modifications of graphene oxide scribed under different controlled atmospheres, including air, N2, Ar, and a 95.5% Ar/H2 mixture.
Abstract: Laser scribing, by far proposed as a method for efficiently transforming graphene oxide into reduced graphene, has been employed, using a CW laser beam, to study the modifications of graphene oxide scribed under different controlled atmospheres, including air, N2, Ar, and a 95 : 5 ( ) Ar/H2 mixture. We have found that laser scribing effects, including chemical composition, order degree, and electrical properties, strongly depend upon the atmosphere during the irradiation. The electrical properties of the various materials, obtained in different atmospheres, have been evaluated with respect to the sensing properties towards humidity, the materials produced in pure Argon yielding the highest sensitivity and the fastest response, while related Raman microspectroscopy measurements showed that both Ar and Ar-H2 mixture produce the highest order among the various samples. The results stress the importance and the potentialities of controlling the irradiation atmosphere in order to tune the composition and electrical properties of the laser-scribed graphene oxide materials.

7 citations