Optical limiting response of Ag₂S nanoparticles synthesized by laser ablation of silver target in DMSO

Abstract

Silver sulfide nanoparticles (Ag 2 S NPs) were synthesized by nanosecond pulsed laser ablation of a silver plate in dimethyl sulfoxide. Ultraviolet-visible absorption spectrometry, X-ray diffraction, and transmission electron microscopy were used to characterize the obtained nanocrystal samples. The mechanisms for optical limiting performance of an Ag 2 S NP colloid were investigated under exposure to nanosecond pulsed laser irradiation at 532 nm. The observed aperture dependence of the Ag 2 S NP limiting performance indicates that the nonlinear scattering plays an important role in the limiting action of the sample. The Ag 2 S NPs may enhance the absorption of laser light by the two-photon absorption process and induce a very high rise in the temperature of the sample, which leads to the formation of scattering centers. [17]. This synthetic flexibility of physical and chemical properties is one of the reasons why nanoparticle suspensions are good candidates for nonlinear optical applications like photonic switches, optical limiters, etc. In particular, optical limiters have received significant attention during recent decades due to the ability to protect human eyes and sensors from intense laser pulses. An ideal optical limiter exhibits high transmission for low-intensity light, while it shows low transmission for intense light. This phenomenon can be caused by various nonlinear light-matter interactions, especially nonlinear absorption, nonlinear refraction, and nonlinear scattering. Many organic materials such as phthalocyanines [18], fullerene families [19], and carbon-black suspensions [20] were reported as good limiters due to their excellent nonlinear optical properties.

Origin of Unusual Excitonic Absorption and Emission from Colloidal Ag2S Nanocrystals: Ultrafast Photophysics and Solar Cell

“…Elemental analysis using energy-dispersive X-ray analysis (EDAX) shows Ag/S ratio remains unchanged (1.9:1) before and after the annealing. Therefore, the only possible explanation for this partial appearance of excitonic feature after this mild annealing can be because of improvement of crystallinity through removal of defects. , Further increase in annealing temperature to 200 °C leads to the segregation of Ag impurity phase, similar to a previous report . Results of cation exchange reaction infer that unwanted defect-related broad absorption blurs the features of excitonic absorption and quenches the excitonic emission.…”

“…Please note that Figure d also suggested ∼140 °C is the optimum temperature to anneal out defects from cation-exchanged Ag 2 S NCs. Higher temperatures may lead to the starting of partial segregation of Ag phase …”

“…After optimizing the excitonic absorption, emission, and solar-cell properties of colloidal Ag 2 S NCs, by minimizing the defects, here we show the ultrafast spectroscopy of the optimized sample. To the best of our knowledge, there are only two prior reports on femtosecond (fs) ultrafast optical absorption studies of colloidal Ag 2 S NCs, and both were probed in the NIR region. , Also, there are two reports on nanosecond nonlinear optical absorption of Ag 2 S NCs. , Out of these spectroscopic investigations, three (refs , , and ) studies were carried out on Ag 2 S NCs that do not exhibit any excitonic absorption. Clearly, ultrafast spectroscopy of high-quality Ag 2 S NCs has remained largely unexplored, which motivated us to study the femtosecond transient absorption (TA) of Ag 2 S NCs probing the visible region (450 to 730 nm) and nanosecond TPA at 532 nm.…”

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation

“…Nanoparticles constituted of metallic salts are also attractive for NLO and OL applications. For instance, Ag 2 S NPs were synthesized by ns pulsed laser ablation of a silver plate in dimethyl sulfoxide, 545 and their OL performance was investigated under irradiation with ns pulses at 532 nm. Ag 2 S NPs samples displayed OL behavior, and the observation of an asymmetrical configuration of the data indicated that nonlinear scattering was occurring in this materials.…”

Novel preparation and near-infrared photoluminescence of uniform core-shell silver sulfide nanoparticle@mesoporous silica nanospheres

“…[1][2][3][4][5] Bulk monoclinic a-Ag 2 S, with a band gap of 1.1 eV, a relatively large absorption coefficient, and excellent optical limiting properties, has been synthesized and used in photoconductors, photovoltaic cells, photo detectors, solar cells, etc. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Recently, the NIR photoluminescent (PL) property of Ag 2 S nanocrystals has been developed. [25][26][27] Wang and co-workers reported the preparation of single-crystalline monodisperse Ag 2 S nanocrystals with a size of about 10 nm by using a single source precursor, which yield the first observation to present the NIR emission at 1058 nm.…”