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Creating heterojunctions or composites by incorporating noble metals offers a remarkable means to modulate the electronic charge transfer and the nonlinear optical (NLO) properties in 2D transition metal dichalcogenides (TMDCs). The response of such 2D‐TMDC‐noble metal composites to femtosecond (fs) infrared (IR) and terahertz (THz) radiation, however, remains vastly unexplored. While the linear optical characteristics of a prototypical 2D‐TMDC, namely, MoSe2 nanosheets incorporated with noble metal (such as Au, Pt, and Ag) nanoparticles in the UV–Vis and the THz spectral range, the NLO characteristics are measured using a 70‐fs pulse at 800 nm excitation is investigated. The results demonstrate a clear reduction of band gap with the incorporation of noble metals in MoSe2, indicating an effective charge transfer mechanism at play. Notably, the MoSe2‐noble metal nanocomposites depicted a significant enhancement in the THz conductivities. In addition, a dramatic 4‐fold enhancement in the third‐order nonlinear coefficient and ≈2‐fold enhancement in the third‐order NLO susceptibility is achieved in MoSe2‐Ag nanocomposite. These results univocally suggest that the noble metal‐based composites with suitable charge transfer channels promote enhanced carrier mobilities and tunable electron transfer dynamics, making these hybrid materials promising candidates for optoelectronic applications both at IR and THz frequencies. [ABSTRACT FROM AUTHOR]

This study explores the use of Halloysite NanoTubes (HNTs) as photocatalysts capable of decomposing organic dyes under exposure to visible or ultraviolet light. Through a systematic series of photocatalytic experiments, we unveil that the photodegradation of Rhodamine B, used as a model cationic dye, is significantly accelerated in the presence of HNTs. We observe that the extent of RhB photocatalytic degradation in 100 min in the presence of the HNTs is ~four times higher compared to that of bare RhB. Moreover, under optimized conditions, the as-extracted photodegradation rate of RhB (~0.0022 min−1) is comparable to that of the previously reported work on the photodegradation of RhB in the presence of tubular nanostructures. A parallel effect is observed for anionic Coumarin photodegradation, albeit less efficiently. Our analysis attributes this discrepancy to the distinct charge states of the two dyes, influencing their attachment sites on HNTs. Cationic Rhodamine B molecules preferentially attach to the outer surface of HNTs, while anionic Coumarin molecules tend to attach to the inner surface. By leveraging the unique properties of HNTs, a family of naturally occurring nanotube structures, this research offers valuable insights for optimizing photocatalytic systems in the pursuit of effective and eco-friendly solutions for environmental remediation. [ABSTRACT FROM AUTHOR]

Naturally occurring halloysite nanotubes (HNTs) have attracted significant scientific interest due to their multifunctional behavior and biocompatibility. However, the application of HNTs in photonics is still unexplored. Here, natural HNTs with different lengths and diameters have been employed as passive scatterers for the generation of random laser (RL) emission from rhodamine B (RhB) in a colloidal phase. Upon pumping at 532 nm, mixed HNT-RhB disordered colloidal systems are shown to yield orange RL emission with a linewidth as small as ∼4 nm. Moreover, a statistical analysis of shot-to-shot correlations among RL modes reveals an obvious photonic paramagnetic to spin-glass transition with increasing pump energy, which is a unique statistical fingerprint of RL. Interestingly, besides acting as scatterers, the HNTs are also found to improve the photostability of RhB molecules. Indeed, HNTs help to better dissipate the excess energy deposited in the gain medium, thus protecting the dye from photodegradation and facilitating the achievement of RL. The results contribute to the theoretical understanding and technical development of low-cost RL devices based on widely available sources in view of multiple prospective applications in photonics. [ABSTRACT FROM AUTHOR]

The efficient monitoring and early detection of viruses may provide essential information about diseases. In this work, we have highlighted the interaction between DNA and a two-dimensional (2D) metal oxide for developing biosensors for further detection of viral infections. Spectroscopic measurements have been used to probe the efficient interactions between single-stranded DNA (ssDNA) and the 2D metal oxide and make them ideal candidates for detecting viral infections. We have also used fully atomistic molecular dynamics (MD) simulation to give a microscopic understanding of the experimentally observed ssDNA-metal oxide interaction. The adsorption of ssDNA on the inorganic surface was found to be driven by favourable enthalpy change, and 5′-guanine was identified as the interacting nucleotide base. Additionally, the in silico assessment of the conformational changes of the ssDNA chain during the adsorption process was also performed in a quantitative manner. Finally, we comment on the practical implications of these developments for sensing that could help design advanced systems for preventing virus-related pandemics. [ABSTRACT FROM AUTHOR]

Piezoelectric materials have drawn significant attention from researchers in the recent past as the piezo-potential, induced by applied external stress, generates an electric field, which paves the way for the creation and transfer of electrons and holes. After the theoretical prediction of the existence of the piezoelectric effect in transition metal dichalcogenides (TMDCs) semiconductors, intense research efforts have been made by various researchers to demonstrate the effect experimentally. In addition 2D TMDCs exhibit layer-dependent tunable electronic structure, strongly bound excitons, enhanced catalytic activity at their edges, and novel spin/pseudospin degrees of freedom. The edge sites and activated basal planes of 2D TMDCs are shown to be highly active toward catalysis of the hydrogen evolution reaction (HER). However, as compared to electrocatalytic or even photocatalytic performances, TMDC materials exhibit poorer piezocatalytic activity, in general. Therefore, a numbers of research strategies have been made to intensify the piezoelectric effect by synthesizing different types of TMDC nanostructures, by coupling the piezoelectric effect with the photocatalytic effect, by doping with other materials, etc. This review discusses various techniques of synthesis of TMDCs nanostructures and the recent progresses in applications of TMDC nanomaterials in piezocatalysis. In the present article, the piezocatalytic dye degradation performances and HER activity using different TMDCs have been reviewed in detail. Different methods of increasing the piezocatalytic activity of various TMDCs nanostructures have been illustrated. Here, it has also been attempted to systematically summarize and provide an outlook of the charge transfer behaviour and catalytic mechanisms in large varieties of TMDC piezocatalysts and piezo-photocatalysts. In addition, advanced applications of TMDC piezocatalytic materials as piezoelectric nanogenerator, piezocatalytic dye degradation, piezo−phototronic dye degradation and HER studies have been highlighted. [ABSTRACT FROM AUTHOR]

There is a growing demand for the development of sustainable electrical energy generation devices with a high energy-to-price ratio. On the other hand, industrial waste, such as fly ash is a hazard to environmental pollution. However, here for the first time, water-based self-rechargeable batteries have been fabricated by using bio-waste (golden shower tree bark ash (TBA)), a rural pollutant (cow dung ash), and industrial pollutant (coal fly ash). The TBA-based battery, out of all three batteries, shows the highest open-circuit voltage of ∼1.48 V and a specific capacity of 183 mAhg−1. Further, the TBA based cell has retained ∼97% columbic efficiency even after 2000 cycles. It has been found that pH of TBA ash is the highest, i.e. ∼12 in presences of tap water and it is found that the TBA ash is composed of a large number of metal oxides. The materials present in the ash powder have generated oxides and hydroxides ions which have, in turn, caused the generation of the potential difference between the two electrodes. The fabricated devices are portable and can power up a large number of electronic gadgets, including light-emitting diodes (LEDs). It is envisioned that this work may open the door to the development of sustainable, environment-friendly, and low-cost bio-waste ash-based self-rechargeable energy devices in future. Environment friendly self-rechargeable water-based bio-waste ash battery. [Display omitted] • Fabrication of commercial electrolyte free, bio-waste based self-rechargeable batteries. • The TBA based battery shows the highest open-circuit voltage of ∼1.45 V. • The TBA-based cell shows the highest specific capacity of 183 mAhg−1. • The TBA-based battery has retained of 97% columbic efficiency even after 2000 cycles. [ABSTRACT FROM AUTHOR]

Syntheses of few‐layered piezocatalysts from nonlayered materials have gained a huge attention of attention in recent years due to their potential applicability in efficient removal of toxic elements from water. Here, a simple scalable bottom up approach consisting of wet‐chemical synthesis method is used to produce the atomically thin (2D)‐wurtzite ZnO: "wurtzene." The presence of a large number of well‐distributed surface defects in the synthesized wurtzene promotes the separation of charge carriers in it via the excellent piezo‐photocatalytic activity and thereby the efficiency of degradation of a test dye (namely methylene blue) is enhanced by ≈5 times. By taking an innovative approach, a piezoelectric driven power cell is also fabricated by using the wurtzene and the highest open circuit voltage is found out to be ≈40 V at 1.0 kPa of applied periodic pressure. The experimental observations are explained with density functional theory calculation. The confinement effect due to reduced dimension plays a crucial role in the wurtzene's excellent piezoelectric response. It is envisioned that the present findings will provided a clear insight into the synthesis of wurtzene with surface defects for highly efficient sunlight driven photocatalytic activity as well as piezoelectric energy harvesting. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A two-step synthesis approach is proposed to synthesize 2D rGO-ZnO (rGZn) nanocomposites. • Cotton smart fabrics have been prepared with the synthesized rGZn nanocomposites. • Synthesized nanocomposites show high photocatalytic and self-cleaning properties. • The amount of ZnO is varied in nanocomposites to achieved high photo-catalytic efficiency. • Methylene blue dye degradation of ∼91% is achieved only within 60 min. Abstract Recently, research activities are focused on development of 2D reduced graphene oxide (rGO) based semiconductor nanocomposite materials for boosting up its catalytic applications. In this work, a rarely reported green synthesis approach has been envisioned to synthesize in-situ 2D rGO-ZnO (rGZn) nanocomposites from Apple juice and zinc acetate. Also the composition of the samples has been optimized to achieve high photocatalytic and self-cleaning properties by the formation of reactive oxidation species. The samples are characterized for their microstructural, optical absorption and photoluminescence properties. It has been tested that rGZn nanocomposites are capable of removing a test dye, namely methylene blue (MB) from water and achieved the highest dye degradation efficiency of ∼91% within only 60 min under UV–vis light irradiation. A smart cotton fabric (CF) coated with rGZn has been prepared and demonstrated its photocatalytic self-cleaning property by degradation of MB, rhodamine B dyes and tea stains on it even under sunlight irradiation, which is scarcely available in the literature. Therefore, this work may open a new avenue of research for low cost and easy synthesis of rGO-semiconductor nanocomposites with high photocatalytic properties for industrial applications as well as for development of rGO based smart fabric for real-life applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nonlinear optical properties of graphene oxide–bimetallic nanocomposite by fs Z-scan technique. • A massive three orders of magnitude enhancement in the two-photon absorption coefficient is observed. • Graphene oxide–bimetallic nanocomposite exhibited intensity dependent switching of saturable absorption to reverse saturable absorption. • The bi-metallic graphene oxide composite has the lowest optical limiting threshold value of ∼4.6 μJ/cm2. Graphene based 2D materials after suitable modification may results into materials with strong nonlinear optical (NLO) responses. Here, incorporation of Au, and Ag nanoparticles (NPs) in graphene oxide (GO) nanosheet (GO_Au_Ag) is carried out for restructuring of its electronic bands. Reshuffling in the electronic band-to-band transitions and their relaxation process is achieved resulting into achievement of high NLO response in GO_Au_Ag than those of pure GO nanosheets, graphene quantum dot (GQD), and nitrogen doped GQD (N-GQD), by fs Z-scan technique. GO, GQD, and N-GQD, shows only two-photon absorption (2PA), with two times larger absorption coefficient (β) in N-GQD than that of GO and GQD. Interestingly, GO_Au_Ag nanocomposite exhibits simultaneous 2PA and three-photon absorption (3PA) under the excitation of the fs laser pulses. In the presence of prolongated relaxation time and transfer of charge between GO and metal's state through excited state absorption (ESA), GO_Au_Ag showed a larger β value than N-GQD and the giant third order nonlinear susceptibility (χ (3)) of ∼10−9 (esu). Furthermore, GO_Au_Ag sample shows the optical limiting threshold of only 4.6 μJ/cm2, smaller than that of N-GQD. [ABSTRACT FROM AUTHOR]

The article focuses on importance of transformation based learning with connection to education for Indian women and states that to empower women more programs need to be developed and higher education for women will become meaningful if education is more holistic and appealing.