Visualization 1: Making few-layer graphene photoluminescent by UV ozonation

Visualization 1 Originally published in Optical Materials Express on 01 November 2016 (ome-6-11-3527

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More results on control devices and discussion on mechanis

Effective Modulation of Interlayer Excitons in WSe₂/WS₂ Heterostructures by Plasmon–Exciton Interaction

Effective charge transfer and carrier separation at the interface are paramount for optimizing the performance of devices based on van der Waals heterostructures. In this investigation, surface plasmons generated by gold nanoparticles are employed to modulate the photocarrier dynamics in WSe2/WS2 heterostructures. The results of pump–probe measurements reveal that the efficiency of carrier transfer across the WSe2/WS2 heterostructure interface can be significantly enhanced via energy transfer mechanisms mediated by gold plasmons. Moreover, the electric field engendered by the plasmonic oscillations can modulate the dipole moment of the interlayer exciton. These well-aligned excitons avoid annihilation, and the extension of the lifetime of the excitons with increased pump power is realized by a screening effect. The findings presented herein offer valuable insights into the active manipulation of charge transfer and extend our understanding of the integral role played by plasmon–exciton coupling in mediating charge separation in van der Waals heterostructures

Shape-Uniform, High-Quality Monolayered MoS₂ Crystals for Gate-Tunable Photoluminescence

Two-dimensional molybdenum disulfide (MoS₂) has recently drawn major attention due to its promising applications in electronics and optoelectronics. Chemical vapor deposition (CVD) is a scalable method to produce large-area MoS₂ monolayers, yet it is challenging to achieve shape-uniform, high-quality monolayered MoS₂ grains as random, diverse crystallographic orientations and various shapes are produced in the same CVD process. Here, we report the growth of high-quality MoS₂ monolayers with uniform triangular shapes dominating (up to 89%) over other shapes on both SiO₂/Si and sapphire substrates. The new confined-space CVD process prevents contamination and helps regulate the Mo/S ratio during the deposition. The as-grown triangular MoS₂ monolayers exhibit grain sizes up to 150 μm and possess better crystalline properties and lighter n-type doping concentration than those of the monolayers grown by common CVD methods. The corresponding field effect transistor devices show high electron mobilities of 50–60 cm² V^–1 s^–1 and positive threshold voltages of 21–35 V. This mild n-type behavior makes it possible to regulate the formation of excitons by back-gate voltage due to the interaction of excitons with free charge carriers in the MoS₂ channel. As a result, gate-tunable photoluminescence (PL) effect, which is rarely achievable for MoS₂ samples prepared by common CVD or mechanical exfoliation, is demonstrated. This study provides a simple versatile approach to fabricating monolayered crystals of MoS₂ and other high-quality transition metal dichalcogenides and could lead to new optoelectronic devices based on gate-tunable PL effect

Synthesis, Optical, and Magnetic Properties of Ba₂Ni₃F₁₀ Nanowires

A low-temperature hydrothermal route has been developed, and pure phase Ba₂Ni₃F₁₀ nanowires have been successfully prepared under optimized conditions. Under the 325 nm excitation, the Ba₂Ni₃F₁₀ nanowires exhibit three emission bands with peak positions locating at 360, 530, and 700 nm, respectively. Combined with the first-principles calculations, the photoluminescence property can be explained by the electron transitions between the t_2g and e_g orbitals. Clear hysteresis loops observed below the temperature of 60 K demonstrates the weak ferromagnetism in Ba₂Ni₃F₁₀ nanowires, which has been attributed to the surface strain of nanowires. Exchange bias with blocking temperature of 55 K has been observed, which originates from the magnetization pinning under the cooling field due to antiferromagnetic core/weak ferromagnetic shell structure of Ba₂Ni₃F₁₀ nanowires

Representative images of immunohistochemical staining showing CLPTM1L is overexpressed in lung cancer relative to normal tissues.

<p>(A) Normal lung tissue (×200); (B) Section from lung adenocarcinoma (×200); (C) Section from lung squamous-cell carcinoma (×200); (D) Section from lung adenocarcinoma (×400).</p

Clinical parameters.

*<p>: p<0.05 vs. not well differentiation group.</p

Knockdown of CLPTM1L increased cisplatin-induced activation of caspase-3/7 and caspase-9.

<p>shRNA-CLPTM1L transfected 95-D cells and control cells were treated with 50 uM cisplatin for 24 h. Caspase-3/7 and caspase-9 activity were measured and the results were represented as fold increase of the activity of the cells without cisplatin treatment. *: p = 0.004 vs NC control group (caspase-3/7) and #: p = 0.000 vs NC control group (caspase-9).</p

Immunochemistry of human lung tissue.

*<p>: p<0.01 vs. adjacent tissues,</p>**<p>: p<0.01 vs. squamous.</p

Overexpression of CLPTM1L in human lung cancer 95-D cells.

<p>(A) The CLPTM1L mRNA level was measured using quantitative real-time PCR in pcDNA3.1(+)-CLPTM1L or pcDNA3.1(+) plasmid transfected cells. *: <i>P</i><0.05 vs control group (p = 0.001). (B) The expression of CLPTM1L protein was investigated using immunocytochemistry. (C) Effects of CLPTM1L overexpression on cell proliferation in the pcDNA3.1(+)-CLPTM1L transfected cells 95-D cells relative to control 95-D cells. (D) Overexpression of CLPTM1L did not change chemosensitivity to cisplatin in human lung cancer 95-D cells transfected with pcDNA3.1(+)-CLPTM1L relative to controls. The cells were treated with the indicated concentrations of cisplatin for 24 h.</p