7 research outputs found
MXene Printing and Patterned Coating for Device Applications
As a thriving member of the 2D nanomaterials family, MXenes, i.e., transition metal carbides, nitrides, and carbonitrides, exhibit outstanding electrochemical, electronic, optical, and mechanical properties. They have been exploited in many applications including energy storage, electronics, optoelectronics, biomedicine, sensors, and catalysis. Compared to other 2D materials, MXenes possess a unique set of properties such as high metallic conductivity, excellent dispersion quality, negative surface charge, and hydrophilicity, making them particularly suitable as inks for printing applications. Printing and pre/post-patterned coating methods represent a whole range of simple, economically efficient, versatile, and eco-friendly manufacturing techniques for devices based on MXenes. Moreover, printing can allow for complex 3D architectures and multifunctionality that are highly required in various applications. By means of printing and patterned coating, the performance and application range of MXenes can be dramatically increased through careful patterning in three dimensions; thus, printing/coating is not only a device fabrication tool but also an enabling tool for new applications as well as for industrialization
MXene Printing and Patterned Coating for Device Applications
As a thriving member of the 2D nanomaterials family, MXenes, i.e., transition metal carbides, nitrides, and carbonitrides, exhibit outstanding electrochemical, electronic, optical, and mechanical properties. They have been exploited in many applications including energy storage, electronics, optoelectronics, biomedicine, sensors, and catalysis. Compared to other 2D materials, MXenes possess a unique set of properties such as high metallic conductivity, excellent dispersion quality, negative surface charge, and hydrophilicity, making them particularly suitable as inks for printing applications. Printing and pre/post-patterned coating methods represent a whole range of simple, economically efficient, versatile, and eco-friendly manufacturing techniques for devices based on MXenes. Moreover, printing can allow for complex 3D architectures and multifunctionality that are highly required in various applications. By means of printing and patterned coating, the performance and application range of MXenes can be dramatically increased through careful patterning in three dimensions; thus, printing/coating is not only a device fabrication tool but also an enabling tool for new applications as well as for industrialization
Tunable Multipolar Surface Plasmons in 2D Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> MXene Flakes
2D
Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> MXenes were recently shown to exhibit intense surface plasmon
(SP) excitations; however, their spatial variation over individual
Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> flakes remains undiscovered. Here, we use scanning transmission
electron microscopy (STEM) combined with ultra-high-resolution electron
energy loss spectroscopy (EELS) to investigate the spatial and energy
distribution of SPs (both optically active and forbidden modes) in
mono- and multilayered Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> flakes. With STEM-EELS mapping, the
inherent interband transition in addition to a variety of transversal
and longitudinal SP modes (ranging from visible down to 0.1 eV in
MIR) are directly visualized and correlated with the shape, size,
and thickness of Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> flakes. The independent polarizability of
Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> monolayers is unambiguously demonstrated and attributed to
their unusual weak interlayer coupling. This characteristic allows
for engineering a class of nanoscale systems, where each monolayer
in the multilayered structure of Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> has its own set of SPs with
distinctive multipolar characters. Moreover, the tunability of the
SP energies is highlighted by conducting <i>in situ heating</i> STEM to monitor the change of the surface functionalization of Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> through annealing at temperatures up to 900 Ā°C. At temperatures
above 500 Ā°C, the observed fluorine (F) desorption multiplies
the metal-like free electron density of Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub> flakes, resulting
in a monotonic blue-shift in the SP energy of all modes. These results
underline the great potential for the development of Ti<sub>3</sub>C<sub>2</sub><i>T</i><sub><i>x</i></sub>-based
applications, spanning the visibleāMIR spectrum, relying on
the excitation and detection of single SPs
Room-Temperature Reactivity Of Silicon Nanocrystals With Solvents: The Case Of Ketone And Hydrogen Production From Secondary Alcohols: Catalysis?
Although silicon
nanoparticles dispersed in liquids are used in
various applications ranging from biolabeling to hydrogen production,
their reactivities with their solvents and their catalytic properties
remain still unexplored. Here, we discovered that, because of their
surface structures and mechanical strain, silicon nanoparticles react
strongly with their solvents and may act as catalysts for the dehydrogenation,
at room temperature, of secondary alcohols (e.g., isopropanol) into
ketones and hydrogen. This catalytic reaction was monitored by gas
chromatography, pH measurements, mass spectroscopy, and solid-state
NMR. This discovery provides new understanding of the role played
by silicon nanoparticles, and nanosilicon in general, in their reactivity
in solvents in general, as well as being candidates in catalysis
Quantum Tunneling Effect in CsPbBr<sub>3</sub> Multiple Quantum Wells
Two-dimensional
(2D) lead halide perovskites (LHPs) have garnered
incredible attention thanks to their exciting optoelectronic properties
and intrinsic strong quantum confinement effect. Herein, we carefully
investigate and decipher the charge carrier dynamics at the interface
between CsPbBr3 multiple quantum wells (MQWs) as the photoactive
layer and TiO2 and Spiro-OMeTAD as electron and hole transporting
materials, respectively. The fabricated MQWs comprise three monolayers
of CsPbBr3 separated by 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline
(BCP) as barriers. By varying the BCP thickness, we show that charge
carrier extraction from MQWs to the corresponding extracting layer
occurs through a quantum tunneling effect, as elaborated by steady-state
and time-resolved photoluminescence measurements and further verified
by femtosecond transient absorption experiments. Ultimately, we have
investigated the impact of the barrier-thickness-dependent quantum
tunneling effect on the photoelectric behavior of the synthesized
QW photodetector devices. Our findings shed light on one of the most
promising approaches for efficient carrier extraction in quantum-confined
systems