Phosphorescent MoS₂ quantum dots as a temperature sensor and security ink

Abstract

The embedding of MoS2 quantum dots in polyvinyl alcohol matrices produces long afterglow phosphorescent materials.

Tunable band gaps and optical absorption properties of bent MoS2 nanoribbons

“…Since the typical lifetime of an exciton in monolayer MoS 2 can be about 10 nanoseconds 48 , it is feasible to optically excite the system from one triplet state to another in the bent nanoribbon. Also, the intersystem crossing in MoS 2 system is realizable, evidenced by the phosphorescence application of MoS 2 quantum dots 49 , and it becomes more realizable in bent nanoribbons since bending usually increases the spin–orbit coupling, which assists in changing the spin during the intersystem crossing process. Besides, by appropriate doping or introducing defects, one may realize combination or hybridization between localized states and edge states in the nanoribbons, creating possible novel quantum states.…”

Enhanced Photoluminescence Quantum Yield of Colloidal MoS2 Quantum Dots by Optimization of Oleic Acid and Oleylamine for Light-Emitting Diode Applications

“…2,3 A detailed study of optical properties of MoS 2 QDs will be beneficial for optimization of PLQY of these similar structured materials also. 29−32 Most of the work on the synthesis of MoS 2 QDs has been focused on mechanical or liquid phase-assisted exfoliation, 10,12,20 chemical vapor deposition, 33,34 and solvothermal methods. 11,17,18,35 The limitation of mass production, long fabrication duration, and small PLQY restricts the application potential of MoS 2 QDs prepared with the above-mentioned techniques.…”

“…The reduction in size in all dimensions in QDs is expected to significantly enhance the optical properties as compared to the monolayer (PLQY ≈ 10 –3 %) due to strong quantum confinement of charge carriers, resulting in a large number of exciton generation. The enhanced optical properties of MoS 2 QDs make them highly suitable for application in optoelectronic devices such as photodetectors, , optical sensors, − electrochromic devices, and light-emitting diodes (LEDs) . The toxicity of QDs such as CdSe, PbS, and CdS curtails their usage in biomedical applications, while the low toxicity MoS 2 QDs is a good substitute. − Apart from enhanced optical properties, the increase in surface-to-volume ratio enables these QDs to find application in catalysis , and energy storage devices such as supercapacitors. − There are other materials in transition metal dichalcogenide family such as WS 2 and MoSe 2 with a bandgap larger than MoS 2 . , A detailed study of optical properties of MoS 2 QDs will be beneficial for optimization of PLQY of these similar structured materials also. − …”

“…Most of the work on the synthesis of MoS 2 QDs has been focused on mechanical or liquid phase-assisted exfoliation, ,, chemical vapor deposition, , and solvothermal methods. ,,, The limitation of mass production, long fabrication duration, and small PLQY restricts the application potential of MoS 2 QDs prepared with the above-mentioned techniques. As an alternative method to synthesize MoS 2 QDs, the vastly used colloidal heat-up method for QD synthesis offers large-scale production with controllable dimensions, size distribution, and surface properties in a short reaction span as compared to reported exfoliation and other methods.…”

High‐Resolution Afterglow Patterning Using Cooperative Vapo‐ and Photo‐Stimulation

“…Room-temperature phosphorescence (RTP) from pure organic molecules has attracted attention for use in bioimaging [1][2][3][4][5] and security media. [6][7][8][9][10][11][12][13][14][15][16][17] Persistent (decay lifetime >0.1 s) RTP (pRTP) enables the detection of emission signals, independent of fluorescent impurities, using cost-effective and small-scale photodetectors with slow response times. [18][19][20] Additionally, pRTP materials enable high-resolution and autofluorescence-free emission DOI: 10.1002/smll.202308103 imaging [21,22] because they have a brighter capability compared with those of conventional long-persistence luminescent materials under strong excitation.…”