Laser‐Directed Assembly of Nanorods of 2D Materials

Abstract

transparency thus connected networks of 1D nanomaterials [5] have been studied as a viable alternative to thin films of indium tin oxide, which suffer from drawbacks such as brittleness and indium scarcity. [6] Materials such as graphene and transition metal dichalcogenides (TMDs) exhibit excellent electrical properties due to their "flat" 2D chemical structure. Sheets or flakes of these materials can allow for large area coverage with high conductivity but typically at the expense of transparency. [7,8] An approach to improving transparency is utilizing these materials in 1D nanorod-like structures. Carbon nanotubes (CNTs) are the most popular 1D variant of graphene and have been utilized to form large area conducting films, although challenges remain with respect to their purification [9,10] and aggregation. [5] As an alternative to CNTs, the synthesis of carbon-based nanorods has been reported by utilizing arc discharge [11] and microwave plasma chemical vapor deposition (CVD) [12] methods. However, the arc discharge method requires an extensive filtering (Soxhlet extraction) and drying process, while the CVD method requires a high power and temperature (e.g., 850 °C). The growth of graphene nanoribbons has also been reported by ultrahigh vacuum thermal evaporation [13] and hydrothermal techniques, [14] yielding lengths of 20-450 nm and widths of 2-40 nm.In regards to TMDs, molybdenum disulfide (MoS 2 ) nanorods have been synthesized via a redox reaction in an aqueous solution (yielding a nanorod mixture of binary oxides (Mo x O y ) and binary sulfides (Mo x S y )), [15] hydrothermal synthesis, [16] and hydrothermal synthesis of MoO 3 nanorods combined with sulfurization. [17] Similar to MoS 2 , the synthesis of tungsten disulfide (WS 2 ) nanorods has been accomplished by lengthy hydrothermal [18,19] and sulfidation [20] methods. Zhang et al. used high energy ball milling of WS 2 powder for 122 h, after which the powder was used as a precursor in a hydrothermal reaction for nanorod growth. [21] Ball milling methods have also been used to produce boron nitride (BN) nanorods. Boron carbide powders were milled for 100 h and subsequently treated with nitrogen at high temperature to produce BN nanorods. [22][23][24] In another approach, Museur et al. synthesized BN nanorods embedded in amorphous boron suboxides (B x O y ) through UV laser irradiation of a compacted BN powder pellet in a high-pressure nitrogen environment. [25] Table 1 summarizes these previous efforts to fabricate nanorods of 2D materials. Many of these methods require Herein, the previously unrealized ability to grow nanorods and nanotubes of 2D materials using femtosecond laser irradiation is demonstrated. In as short as 20 min, nanorods of tungsten disulfide, molybdenum disulfide, graphene, and boron nitride are grown in solutions. The technique fragments nanoparticles of the 2D materials from bulk flakes and leverages molecular scale alignment by nonresonant intense laser pulses to direct their assembly into nanorods up to several micrometers i...

Synthesis of Two-Dimensional Plasmonic Molybdenum Oxide Nanomaterials by Femtosecond Laser Irradiation

“…17,21 Therefore, femtosecond laser irradiation has been used to fabricate quantum dots 19,20 and one-dimensional nanoparticles. 17,18,21 In addition, our previous research has demonstrated that the MoS 2 quantum dots fabricated by femtosecond laser irradiation in 50% ethanol/water have abundant oxygen-rich groups. 19 Herein, we introduce an efficient one-pot process to synthesize substoichiometric molybdenum oxide nanosheets from MoS 2 by femtosecond laser irradiation.…”

“…The femtosecond laser is of great interest in nanomaterial fabrication thanks to the high electric field and tunable light polarization directions. − The high electric field can strip the electrons out of bulk materials to break chemical bonds and cause other interatomic interactions. As a result, the bulk materials can be dissociated into nanoparticles.…”

Nanomechanical Gas Sensing with Laser Treated 2D Nanomaterials

“…Solutions of multilayered 2D nanoparticles were fabricated using a previously reported femtosecond laser treatment process, [42][43][44][45][46] where commercially purchased flakes were irradiated in solution by a laser generated with a 1 kHz Ti:Sapphire regenerative amplifier with a central wavelength of 800 nm, pulse duration of 35 fs, and an average power 2 W. A highly concentrated (6.2 mg mL −1 ) graphene oxide solution was treated for 1 and 1.5 h to observe the effect of laser treatment time on the sensor response. To study the effect of dopant atoms, graphene oxide was doped with boron nitride (BN) by adding 5% and 15% of boron nitride by volume.…”

Laser Synthesis and Microfabrication of Micro/Nanostructured Materials Toward Energy Conversion and Storage

“…For the light-thermal conversion materials, not only excellent optical and thermal properties are essential, economic practicality and manufacturing simplicity on a large scale should also be taken into account. The laser processing technique provides a reliable and cost-effective strategy for fabricating nanomaterials with broad-spectrum https://doi.org/10.1007/s40820-020-00577-0 © The authors [144] https://doi.org/10.1007/s40820-020-00577-0 © The authors solar energy absorption on a large scale. In particular, these laser-microfabricated materials are widely applied to various photothermal conversion, anti-reflection and light harvesting applications [152,153].…”

“…Furthermore, the catalytic conversion of quinoline derivatives with methyl, hydroxyl, and halogen groups into corresponding 1,2,3,4-tetrahydroquinolines was also realized by this liberated catalyst [ 130 ]. Musselman et al [ 144 ] utilized the nonresonant intense pulsed laser to fragment and then direct the 2D materials from bulk flakes to assembled nanorod structures. The obtained graphene nanorods, MoS 2 nanorods, WS 2 nanorods and BN nanorods suggested the potential in transparent conducting applications.…”