High selectivity in water soluble MoS₂ quantum dots for sensing nitro explosives

Abstract

Rapid and selective detection of nitro explosives is one of the most promising issues concerning global security. Intensive research has already been carried out, however, the selectivity is still lacking. In the present work, water soluble MoS 2 quantum dots (QDs) are synthesized through a bottom-up approach using (NH 4 ) 6 Mo 7 O 24 Á4H 2 O and Na 2 S as molybdenum and sulfur sources, respectively, and 1,4-diaminobutane as the capping agent. The as-synthesized QDs detect 2,4,6-trinitrophenol (TNP) selectively up to 2.04 ppm and the selectivity reaches 490% which is remarkably higher than the earlier results. In addition to predominant electron transfer (ET) that occurs mostly in fluorescence quenching processes, Forster resonance energy transfer (FRET) also occurs here. As a result of the occurrence of both these ET and FRET processes, high selectivity is achieved for the present samples. The unique advantage of using QDs is the tuning of photoluminescence as a function of dot size to become comparable with the absorption spectra of the TNP to perform the FRET mechanism.

Synthesis of MoS2 Quantum Dots Uniformly Dispersed on Low Dimensional MoS2 Nanosheets and Unravelling its Multiple Emissive States

“…MoS 2 QDNS displayed a broad, excitation dependent fluorescence emission response (Figure B) covering a large region of the visible spectrum, owing to polydispersity of the system, as reported elsewhere ,, . The quantum yield of MoS 2 QDNS was calculated using quinine sulphate as standard at 330 nm excitation and was found to be 3.7 %, comparable to many of the reported MoS 2 QDs ,.…”

“…Hence, we hypothesize that the broad PL emission spectra of MoS 2 QDNS can be split into three regions. The ‘lower wavelength emission’ (referred as region I ) which comes exclusively from small QDs, and the ‘moderate wavelength emission’ (referred as region II ) owing to the synergistic contribution of both QDs and the nanosheets ,. Lastly, the ‘higher wavelength emission’ (referred as region III ) is arising solely from nanosheets .…”

A green luminescent MoS2–CdTe hybrid nanostructure synthesized through surface charge interaction

“…Recently transition metal dichalcogenide (TMDC) quantum dots have been intensively studied because of their superior optical properties. 1,2 Transition metal dichalcogenide materials are a new class of materials which are of vivid interest in the elds of semiconductor nanoscience and optoelectronics. [3][4][5][6] Among metal dichalcogenides, MoS 2 quantum dots (QDs) have become a centre of attraction for researchers due to their wide variety of properties in the semiconductor industry for optoelectronic applications and energy harvesting.…”

Biosensors Based on Advanced Sulfur-Containing Nanomaterials

“…Their stable photoelectric properties made sulfur-containing quantum dots be adapted as excellent probes in biosensors via various strategies, such as electrochemical, PEC, PL and ECL strategy [ 113 , 114 , 115 ]. Soluble sulfur-containing quantum dots can react with biomolecules, thus biosensors for detection biomolecules could be established through specific physiochemical reactions between them [ 81 , 116 , 117 ]. Functionalization of sulfur-containing quantum dots (especially, sulfide quantum dots) with different stabilizing agents to form surface groups can enhance their hydrophilicity and interaction ability with other biomolecules [ 115 , 118 , 119 , 120 ].…”