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Pulsed laser ablation in liquid technique (PLAL) had started getting attention in late 1990, particularly for the production of the nanomaterials due to its easy handling and room-temperature synthesis process. Soon after the initial demonstration of nanomaterials generation from the PLAL technique, PLAL gradually becomes a green, facile and inexpensive method for the generation of ultrapure carbon nanomaterials (CNMs). In the past two decades, different allotropic forms of CNMs have been fabricated by using PLAL techniques such as graphene/graphene oxide nanosheet, carbon nanotubes, graphene oxide quantum dots, nanodiamonds, carbogenic nanoparticles, polyynes and carbon-encapsulated metal-based nanoparticles. In this review article, we offer a comprehensive discussion on the progress achieved in the design and development of the PLAL method for the production of CNMs only (the year 1998–2020). Firstly, we have introduced the different types of PLAL methods widely used for CNMs fabrication. Secondly, the different types of factors affecting the physicochemical (structural, morphological, optical) properties of CNMs and the efficiency of CNMs production from PLAL method have been summarized in detail. The laser parameters and experimental conditions of the PLAL method, that affecting the physicochemical properties and efficiency of CNMs production are laser wavelengths, pulse duration and repetition rate, ablation duration, per-pulse energy density (fluence), PLAL setup design and nature of solvents. The results from different spectroscopic techniques for each kind of CNMs have been discussed thoroughly, to unambiguously differentiate the structural integrity of the CNMs from one another. Finally, the uses of CNMs for different applications in the present time, existing challenges in the PLAL methods and the future outlook of laser-assisted synthesized CNMs for novel applications were also discussed.

In this report, silver nanoparticles (Ag-NPs) were prepared by pulsed laser ablation of the silver nitrate salt solution using Nd:YAG laser. Trisodium citrate (TSC) is used as a stabilizing/reducing agent for nanoparticles. Under different laser ablation durations, the morphology of nanoparticles changed. Nanoparticles showed the average size ranging from 5 to 31 nm for 20–80 min of ablation. The theoretical and experimental estimation of the particle sizes is done. Butterfly-shaped silver nanoparticles have been tested for the room-temperature clad-modified fiber optic gas sensors sensitivity with ammonia and ethanol gas. The clad-modified optical fiber sensor exhibits distinct linear variation in the spectral peak intensity with the ammonia concentration (0–500 ppm). The characteristics of the gas sensors when exposed to ethanol and ammonia gases were used for studying the sensor selectivity. The results exhibited good sensor response and selectivity for ammonia with sensitivity of 64 counts/ppm and sensitivity percentage of 27%, whereas for ethanol, sensitivity of 9.5 counts/ppm and sensitivity percentage of only 4% were observed.

This paper reports on the fiber optic gas sensing characteristics of clad-modified Cu-doped ZnO nanopowder for the detection of ammonia, ethanol, methanol and acetone gases at various concentration (0–500 ppm). Pure and Cu-doped (1, 3 and 5 mol%) ZnO samples were fabricated and characterized for its structural, optical and morphological properties. Among the samples studied, the sensor containing 5 mol % Cu shows very good response to acetone with the highest gas sensitivity when compared with other gases. Moreover, it exhibits fast response/recovery time (12 and 15 s) and good selectivity.

The present study employed laser ablation to obtain fluorescent carbon nanoparticles (CNPs) using inexpensive and easily available Bougainvillea alba flower juice extract as the source. The laser ablation of flower juice extract was carried out using 355 nm wavelength of Nd: YAG pulsed laser for 60 min. HR-TEM studies showed the presence of both larger (about 60 nm) and smaller size (about 10 nm) CNPs and average particle size was found to be about 25 nm. Crystalline structure was also observed in CNPs, whose interplanar lattice spacing was 0.27 nm, indicating the contracted lattice spacing from usual graphitic structure. XRD and Raman analysis showed that the crystalline CNPs correspond to non-perfect graphitic carbon structure. Optical spectroscopic studies revealed the down-conversion of photoluminescence emission at 485 nm under the excitation wavelength of 400 nm. The average fluorescence lifetime of carbon nanoparticles was estimated as 1.1 ns from time-resolved spectroscopy. The CNPs were found to be non-toxic to human vein endothelial cells and internalized into the cells with high intensity up to 24 h. Two distinct PL emissions were observed with the large particles emitting at the longer wavelength localized predominantly in the cytosol and smaller particles emitting at the shorter wavelength concentrated on the nuclear membrane. The results suggest that the CNPs are biocompatible and have the potential for bioimaging applications.