Silicon compatible wafer scale MoS2 heterojunctions are reported for the first time using colloidal quantum dots. Size dependent direct band gap emission of MoS2 dots are presented at room temperature. The temporal stability and decay dynamics of excited charge carriers in MoS2 quantum dots have been studied using time correlated single photon counting spectroscopy technique. Fabricated n-MoS2/p-Si 0D/3D heterojunctions exhibiting excellent rectification behavior have been studied for light emission in the forward bias and photodetection in the reverse bias. The electroluminescences with white light emission spectra in the range of 450–800 nm are found to be stable in the temperature range of 10–350 K. Size dependent spectral responsivity and detectivity of the heterojunction devices have been studied. The peak responsivity and detectivity of the fabricated heterojunction detector are estimated to be ~0.85 A/W and ~8 × 1011 Jones, respectively at an applied bias of −2 V for MoS2 QDs of 2 nm mean diameter. The above values are found to be superior to the reported results on large area photodetector devices fabricated using two dimensional materials.

Highly luminescent MoS 2 nanocrystals (NCs) with controlled size distribution have been achieved using a simple yet inexpensive and impurity free sono-chemical exfoliation method followed by gradient centrifugation. The size of nanocrystals could be varied within the diameter range of ∼4 to 70 nm. Typical MoS 2 nanocrystal has exhibited high crystalline quality with 0.25 nm lattice fringe spacing for (002) planes for 2-H phase of MoS 2 . Raman spectra has revealed that both out-of-plane and in-plane vibrational modes are stiffen due to the edge effect of MoS 2 NCs. The size tunable optical properties of MoS 2 NCs have been investigated by optical absorption and photoluminescence spectroscopy. The coexistence of direct band gap emission from 2D MoS 2 nanosheets and quantum confined nanocrystals has been achieved. A strong and tunable photoluminescence (560−518 nm) emission due to the quantum size effect of tiny NCs below a critical dimension is reported for the first time. The photocurrent measurement of the Au/MoS 2 −NCs/Au junction has been performed at room temperature to investigate the optical responsivity and switching characteristics, demonstrating the potential of MoS 2 nanocrystals for next generation photonic devices.

We report the fabrication and optical response of boron-doped single silicon nanowire-based metal-semiconductor-metal photodetector. Typical single nanowire devices with diameter of ∼80-100 nm and electrode spacing of ∼1 μm were made using electron-beam lithography from nanowires, grown by a metal-assisted chemical etching process. A high responsivity, of the order of 10(4) A W(-1), was observed even at zero bias in a single nanowire photodetector with peak responsivity in the near-infrared region. The responsivity was found to increase with increasing bias and decreasing nanowire diameter. Finite element based optical simulation was proposed to explain the diameter dependent performance of a single nanowire. The observed photoresponse is sensitive to the polarization of exciting light source, allowing the device to act as a polarization-dependent near-infrared photodetector.

Template-free, bottom-up synthesized, micron sized few layer 2H-MoS2for photodetector and photocatalytic applications.

The coronavirus disease‐2019 (COVID‐19) pandemic caused by severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) has already resulted in a huge setback to mankind in terms of millions of deaths, while the unavailability of an appropriate therapeutic strategy has made the scenario much more severe. Toll‐like receptors (TLRs) are crucial mediators and regulators of host immunity and the role of human cell surface TLRs in SARS‐CoV‐2 induced inflammatory pathogenesis has been demonstrated recently. However, the functional significance of the human intracellular TLRs including TLR3, 7, 8, and 9 is yet unclear. Hitherto, the involvement of these intracellular TLRs in inducing pro‐inflammatory responses in COVID‐19 has been reported but the identity of the interacting viral RNA molecule(s) and the corresponding TLRs have not been explored. This study hopes to rationalize the comparative binding of the major SARS‐CoV‐2 mRNAs to the intracellular TLRs, considering the solvent‐based force‐fields operational in the cytosolic aqueous microenvironment that predominantly drives these interactions. Our in silico study on the binding of all mRNAs with the intracellular TLRs depicts that the mRNA of NSP10, S2, and E proteins of SARS‐CoV‐2 are possible virus‐associated molecular patterns that bind to TLR3, TLR9, and TLR7, respectively, and trigger downstream cascade reactions. Intriguingly, binding of the viral mRNAs resulted in variable degrees of conformational changes in the ligand‐binding domain of the TLRs ratifying the activation of the downstream inflammatory signaling cascade. Taken together, the current study is the maiden report to describe the role of TLR3, 7, and 9 in COVID‐19 immunobiology and these could serve as useful targets for the conception of a therapeutic strategy against the pandemic.

Microfilarial protein appears to be a new ligand of TLR4 from W. bancrofti. Determination of its functional attributions in the host-parasite relationship, especially immunopathogenesis of filarial infection, may improve our understanding.

A DNA-hydrogel, produced using calf-thymus DNA and a 2′,4′,6′-tri(4-pyridyl)pyridine based luminescent supramolecular hydrogel, can stabilize sunray mediated photochemically synthesized bio-compatible, luminous Ag-NPs.

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