Ultrathin Bi Nanosheets with Superior Photoluminescence

et al. 2020

Materials Today

The rise of nanotechnology has been propelled by low dimensional metals. Albeit the long perceived importance, synthesis of freestanding metallic nanomembranes, or the so-called 2D metals, however has been restricted to simple metals with a very limited in-plane size (< 10 m). In this work, we developed a low-cost method to synthesize 2D metals through polymer surface buckling enabled exfoliation. The 2D metals so obtained could be as chemically complex as high entropy alloys while possessing in-plane dimensions at the scale of bulk metals (> 1 cm). With our approach, we successfully synthesized a variety of 2D metals, such as 2D high entropy alloy and 2D metallic glass, with controllable geometries and morphologies.Moreover, our approach can be readily extended to non-metals and composites, thereby opening a large window to the fabrication of a wide range of 2D materials of technologic importance which have never been reported before.

Section: As Seen Inmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

The controlled large-area synthesis of two dimensional metals

Wang

et al. 2020

Materials Today

“…[39] We believe that our findings might hold key importance in understanding nanoscale optical responses from ultrathin Bi 2 Te 3 NSs and help realize next-generation photonic/optoelectronic devices such as flexible and transparent light-emitting diodes (LEDs), lasers, and solar cells. Significant PL enhancement and quenching with a number of QLs in Bi 2 Te 3 NSs has been observed, while thickness modulation as an effective route to control visible SPR modes and intensities is reported in this work.…”

Section: Introductionmentioning

confidence: 88%

“…Furthermore, this method has been successfully implemented recently for the fabrication of ultrathin bismuth (Bi) nanosheets. [39] We believe that our findings might hold key importance in understanding nanoscale optical responses from ultrathin Bi 2 Te 3 NSs and help realize next-generation photonic/optoelectronic devices such as flexible and transparent light-emitting diodes (LEDs), lasers, and solar cells.…”

Section: Introductionmentioning

confidence: 88%

Ultrahigh Room‐Temperature Photoluminescence from Few to Single Quintuple Layer Bi₂Te₃ Nanosheets

Hussain

Advanced Optical Materials

Lang

et al. 2018

Self Cite

photoluminescence is considered as one of the primary figures of merit for a 2D semiconductor to be a promising material for nano-optoelectronic, [10,11] sensing, [12,13] and photodetector applications. [14,15] Therefore, it remains challenging to achieve substantial room-temperature photoluminescence response from Bi 2 Te 3 nanocrystals. Additionally, surface plasmon resonance (SPR) defines collective oscillations of conduction electrons and has been attracting highly devoted research interest owing to its promising applications in on-chip subwavelength electro-optical devices, [16][17][18] sensing, [19,20] and energy harvesting. [15,[20][21][22] Due to limited plasmonic materials and modulation methods, effective control over the energy modes and intensities of surface plasmon resonances in the visible region remains challenging.The effective mass approximation (EMA) model describes the opening of bandgaps in ultrathin nanostructures, due to quantum confinement effects. [23] Therefore, dimensionally restricted 2D nanocrystals of Bi 2 Te 3 might provide an opportunity to achieve remarkably enhanced PL properties through the bandgap opening/transition and potentially hold SPR. In recent past, 2D nanocrystals of Bi 2 Te 3 have been reported to support surface plasmons and exhibit PL responses. For instance, visible SPR from 2D Bi 2 Te 3 nanoplates by cathodoluminescence [24] and tunablity of visible SPR modes by Se doping in Bi 2 Te 3 [25] have been demonstrated using PL spectroscopy. Meanwhile, PL spectroscopy, in particular, offers a great opportunity to study quantum confinement-induced exciting phenomena originating from light-matter interactions at the nanoscale. The size-dependent characteristics and physical Owing to its narrow indirect bandgap, bulk bismuth telluride (Bi 2 Te 3 ) exhibits exceptionally low room-temperature photoluminescence (PL). Consequently, it remains challenging to achieve promising optical and optoelectronic performance from Bi 2 Te 3 . Moreover, due to the lack of plasmonic materials and available modulation methods, it is challenging to effectively control the surface plasmon resonance intensities in the visible region. Herein, thickness-dependent photoluminescence studies unveil ultrahigh (282-fold) room-temperature photoluminescence (visible) from 20 quintuple layer Bi 2 Te 3 nanosheets (NSs) compared to 200 quintuple layer NSs, attributable to a significant bandgap opening. Intriguingly, considerable photoluminescence quenching is observed beyond the thickness of 20 quintuple layer Bi 2 Te 3 . The PL emission is further optimized with reference to the number of quintuple layers, and the mechanism possibly responsible for such PL behavior is elucidated. Moreover, the thickness modulation is put forward as an effective strategy to control visible surface plasmon resonance energy modes and their intensities. Bi 2 Te 3 nanosheets with large area and high crystallinity are fabricated on various silicon substrates by a facile hot-pressing strategy, which facilitates investigation of in...

“…Recently, 2D materials such as graphene, metal oxide, metal carbide, metal dichalcogenides, and pure metal, have played an important role in electronics, sensors, optics, electrocatalysis, and energy storage, owing to the unique atomic thin feature, high specific surface area, and large aspect ratios. Many methods for the preparation of 2D materials have been explored, including liquid phase exfoliation (LPE), mechanical repeated folding and calendaring (RFC), chemical vapor deposition (CVD) or van der Waals epitaxy approach, and salt‐templated or molten salt‐templated method (MSM) .…”

mentioning

confidence: 99%

Rapid and Low‐Temperature Salt‐Templated Production of 2D Metal Oxide/Oxychloride/Hydroxide

et al. 2019

Small

2D materials have played an important role in electronics, sensors, optics, electrocatalysis, and energy storage. Many methods for the preparation of 2D materials have been explored. It is crucial to develop a high‐yield, rapid, and low‐temperature method to synthesize 2D materials. A general, fast (5 min), and low‐temperature (≈100 °C) salt (CoCl2·6H2O)‐templated method is proposed to prepare series of 2D metal oxides/oxychlorides/hydroxides in large scale, such as MoO3, SnO2, SiO2, BiOCl, Sb4O5Cl2, Zn2Co3(OH)10 2H2O, and ZnCo2O4. The as‐synthesized 2D materials possess an ultrathin feature (2–7 nm) and large aspect ratios. Additionally, these 2D metal oxides/oxychlorides/hydroxides exhibit good electrochemical properties in energy storage (lithium/sodium‐ion batteries) and electrocatalysis (hydrogen/oxygen evolution reaction).