- Award ID(s):
- 1728309
- NSF-PAR ID:
- 10274630
- Date Published:
- Journal Name:
- Nanoscale
- Volume:
- 12
- Issue:
- 45
- ISSN:
- 2040-3364
- Page Range / eLocation ID:
- 23116 to 23124
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
null (Ed.)Two-dimensional (2D) transition metal dichalcogenide (TMD) layers have gained increasing attention for a variety of emerging electrical, thermal, and optical applications. Recently developed metallic 2D TMD layers have been projected to exhibit unique attributes unattainable in their semiconducting counterparts; e.g. , much higher electrical and thermal conductivities coupled with mechanical flexibility. In this work, we explored 2D platinum ditelluride (2D PtTe 2 ) layers – a relatively new class of metallic 2D TMDs – by studying their previously unexplored electro-thermal properties for unconventional window applications. We prepared wafer-scale 2D PtTe 2 layer-coated optically transparent and mechanically flexible willow glasses via a thermally-assisted tellurization of Pt films at a low temperature of 400 °C. The 2D PtTe 2 layer-coated windows exhibited a thickness-dependent optical transparency and electrical conductivity of >10 6 S m −1 – higher than most of the previously explored 2D TMDs. Upon the application of electrical bias, these windows displayed a significant increase in temperature driven by Joule heating as confirmed by the infrared (IR) imaging characterization. Such superior electro-thermal conversion efficiencies inherent to 2D PtTe 2 layers were utilized to demonstrate various applications, including thermochromic displays and electrically-driven defogging windows accompanying mechanical flexibility. Comparisons of these performances confirm the superiority of the wafer-scale 2D PtTe 2 layers over other nanomaterials explored for such applications.more » « less
-
A new type of soft actuators based on a vertical stack of nanoporous 2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐oxidized cellulose nanofibers (TOCNs) and atomically thin 2D platinum ditelluride (PtTe2) layers is reported. The actuation of TOCNs is driven by the interfacing 2D PtTe2layers whose electrothermal proficiency precisely controls their hydration/dehydration states sensitive to mechanical deformation. These vertically stacked TOCN/2D PtTe2actuators present excellent actuation characteristics such as high linearity of bending curvature versus applied voltage and well‐preserved reversibility during cyclic operations. Most notably, they exhibit an extremely large weight‐lifting ratio, i.e., ≈1000 times the mass of the TOCN layers, confirming superior mechanical robustness. Furthermore, complicated actuations such as twisting in a 3D manner are demonstrated by judiciously controlling the surface wettability of TOCN layers. This study unveils opportunities for CNFs and 2D materials for actuator applications, as well as suggests new design strategies broadly applicable to soft robotics and biomimetic devices.
-
Abstract Biomorph actuators composed of two layers with asymmetric thermal expansion properties are widely explored owing to their high mechanical adaptability. Electrothermal nanomaterials are employed as the Joule heating components in them for controlled thermal expansion, while their large integration thickness often limits resulting actuation performances. This study reports high‐performance ultrathin soft biomorph actuators enabled by near atom‐thickness 2D platinum ditelluride (PtTe2) layers—a new class of emergent metallic 2D transition metal dichalcogenides. The actuators employ wafer‐scale 2D PtTe2layers sandwiched in between two polymer films of largely mismatched thermal expansion coefficients, which are electrically biased to generate Joule heating. This electrical‐to‐thermal conversion causes the asymmetric expansion of the polymers achieving outstanding actuation motions; i.e., large bending curvature, fast responsiveness, as well as high reversibility and endurance, which surpass the performances of previously explored graphene‐based actuators with much smaller dimensions. Furthermore, the 2D PtTe2layers‐enabled actuators are demonstrated to function as soft grippers in lifting and relocating heavier objects, implying the great potential of near atom‐thickness materials in biomimetic devices.
-
null (Ed.)Two-dimensional (2D) molybdenum disulfide (MoS 2 ) layers are suitable for visible-to-near infrared photodetection owing to their tunable optical bandgaps. Also, their superior mechanical deformability enabled by an extremely small thickness and van der Waals (vdW) assembly allows them to be structured into unconventional physical forms, unattainable with any other materials. Herein, we demonstrate a new type of 2D MoS 2 layer-based rollable photodetector that can be mechanically reconfigured while maintaining excellent geometry-invariant photo-responsiveness. Large-area (>a few cm 2 ) 2D MoS 2 layers grown by chemical vapor deposition (CVD) were integrated on transparent and flexible substrates composed of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNs) by a direct solution casting method. These composite materials in three-dimensionally rollable forms exhibited a large set of intriguing photo-responsiveness, well preserving intrinsic opto-electrical characteristics of the integrated 2D MoS 2 layers; i.e. , light intensity-dependent photocurrents insensitive to illumination angles as well as highly tunable photocurrents varying with the rolling number of 2D MoS 2 layers, which were impossible to achieve with conventional photodetectors. This study provides a new design principle for converting 2D materials to three-dimensional (3D) objects of tailored functionalities and structures, significantly broadening their potential and versatility in futuristic devices.more » « less
-
Abstract Heterogeneous integrations of functionally and chemically distinct materials have been explored to develop promising building blocks for opto‐electronic device applications. Recently, the Van der Waals (vdW)‐assembly of near atom thickness materials has provided excellent opportunities beyond what has been previously been difficult to realize. However, its up‐to‐date demonstrations remain far from achieving the scalability and versatility demanded for practical device applications, that is, the integration is generally demonstrated with intrinsically layered 2D materials of very small lateral dimensions. Herein, the large centimeter‐scale vdW assembly of two different materials with structurally, chemically, and functionally distinct properties, that is, 2D platinum ditelluride (PtTe2) metallic multilayers and non‐layered 3D semiconducting platinum sulfide (PtS) are reported. Both materials are precisely delaminated from their growth wafers inside water and are subsequently integrated on unconventional substrates of desired functionalities. The large‐area vdW‐assembled 2D/3D PtTe2/PtS hetero‐materials on flexible substrates exhibit an excellent photodetection in a spectral range of visible‐to‐near infrared (NIR) wavelength, which is well preserved under severe mechanical deformation. This study paves the way for exploring large‐area flexible opto‐electronic devices solely based on near atom thickness materials.