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The development of robust and efficient photocatalytic constructs for boosting the water oxidation reaction (WOR) is needed for establishing a sunlight-driven renewable energy infrastructure. Here, we synthesized plasmonic core–shell nanoconstructs consisting of triangular gold nanoprism (AuTNP) core with mixed manganese oxide (MnOx) shell for photoelectrocatalytic WOR. These constructs show electrocatalytic WOR with a low onset overpotential requirement of 270 mV at pH 10. Photoexcitation showed further enhancement of their catalytic activity resulting in ∼15% decrease of the onset overpotential requirement along with the generation of photocurrent density of up to 300 μA/cm2. We showed that such light-driven enhancement of AuTNP@MnOx dyad's catalytic activity toward the WOR process includes contributions from both photocatalytic (hot carriers driven) and photothermal effects with photothermal effect playing the major role for wavelength between 532 and 808 nm. The contribution from the photocatalytic effect is appreciable only for high-energy excitations near the interband region, while the photothermal effect largely dominates for lower energy excitations near the LSPR wavelengths of the dyad. [ABSTRACT FROM AUTHOR]

Conventional amine‐capped perovskite nanocrystals (A‐PNCs) often show microscopic fluctuation (blinking) of photoluminescence (PL) between bright and near‐background (dark) states. The transient dark phases spanning milliseconds (ms) to several seconds timescale typically owe to the non‐radiative (NR) fate of charge carriers in crystal defect states, limiting the PNC's efficiency in optoelectronics. A PL study of a novel trioctylphosphine (TOP) capped rhombic cuboctahedron‐shaped amine‐free (AF) PNC is presented, demonstrating their fascinating nonblinking nature. While oleylamine‐capped hexahedron A‐PNCs as a reference system show long dark states, their population is completely suppressed in ≈90% of AF‐PNCs with random large‐amplitude PL fluctuations several times above the background. The PL trajectories of AF‐PNCs primarily comprise constant power spectral densities (PSDs) which are unprecedented and deviate from power‐law distribution as observed for A‐PNCs and most of the other blinking nanocrystals. Such signature of PSDs and frame‐by‐frame intensity jump analysis indicate a fast (<

The mitochondrion has emerged as one of the uncommon targets in cancer therapeutics due to its involvement in cancer generation and progression. Consequently, nanoplatform mediated delivery of anti-cancer drugs into the mitochondria of cancer tissues demonstrated immense potential in cancer treatment. In the last couple of decades, gold nanoparticles have gained incredible attention in biomedical applications due to their easy synthesis, size-shape tenability, optical properties and outstanding photothermal ability. However, application of gold nanoparticles to target mitochondria to induce the chemo-photothermal effect in cancer has remained in its infancy. To address this, herein we have engineered dog-bone shaped gold nanoparticles (Mito-AuDB-NPs) comprising cisplatin and 10-hydroxycamptothecin as chemotherapeutic drugs along with the triphenylphosphonium (TPP) cation for mitochondria homing. Mito-AuDB-NPs exhibited a remarkable increase in temperature till 56 °C upon 18 min irradiation with 740 nm NIR LED light with a power density of 0.9 W cm−2. These Mito-AuDB-NPs successfully homed into the mitochondria of HeLa cervical cancer cells within 1 h and induced mitochondrial outer membrane permeabilization (MOMP) under the chemo-photothermal effect leading to the generation of reactive oxygen species (ROS). This Mito-AuDB-NP-mediated mitochondrial damage triggered programmed cell death (apoptosis) by decreasing the expression of anti-apoptotic Bcl-2/Bcl-xl and increasing the expression of pro-apoptotic BAX followed by caspase-3 cleavage towards extraordinary HeLa cell killing in a synergistic manner without showing toxicity towards non-cancerous RPE-1 human epithelial retinal pigment cells. We anticipate that this dog-bone shaped gold nanoparticle-mediated chemo-photothermal impairment of mitochondria in the cancer cells can open a new direction towards organelle targeted cancer therapy. [ABSTRACT FROM AUTHOR]

Fast and accurate determination of ethanol concentration is important in alcohol industries for testing the purity and quality of their products. Here, we demonstrate a quick, robust, and accurate technique to estimate the concentration of ethanol in aqueous solutions. Our method utilizes the principle of diffraction of light in the presence of high frequency ultrasound waves that create diffraction grating in solution. A monochromatic light interacts with this acoustic grating and produces an intensity distribution pattern, which was used to determine the ethanol concentration. We measured ethanol concentrations in various alcoholic solutions and beverages at room temperature with very high accuracy down to 2 % over a concentration range of 30–100 %. The experimental results have been supported with analytical calculations and simulations. We believe that our method will benefit alcohol production industries and lead to the development of portable, inexpensive, and reliable ethanol concentration measurement devices. [ABSTRACT FROM AUTHOR]

A combination of fluorescence spectroscopy and quantum chemical calculations is used to study the extent of fluorescence enhancement of an epicocconone in different surfactant assemblies, which are found to be very different from each other. The analysis reveals that the depth-dependent microviscosity highly affects the fluorescence quantum that further proves the involvement of fluorophore as a dual emitting marker for fluorescence microscopy.

Bimetallic nanoparticle dyads consisting of a plasmonic core and a catalytic metal shell have attracted significant attention in the context of solar-driven photocatalysts. However, a pertinent design considering both the optical properties of the core and shell and the thickness of the shell material is scarce. Through experiments and simulations, we demonstrated that the photocatalytic efficiency of the Au triangular nanoprisms@Pd (AuTP@Pd) core@shell dyad largely depends on the thickness of the catalytic metal shell. For a lower thickness, the dyad showed enhanced photocatalytic activity compared to bare AuTPs. However, for a higher thickness, the dyad's catalytic activity reduced drastically and showed even lower catalytic activity than pristine AuTPs. From simulations, we showed that for a thin Pd layer, charge carriers were essentially generated at the Pd shell itself and thereby could be easily extracted and utilized. However, a thicker Pd shell screened the plasmonic core and reduced the charge-carrier formation. These findings will be relevant for the optimization of the bimetallic plasmonic catalyst design. [ABSTRACT FROM AUTHOR]

This paper presents a method for simultaneously determining multiple trajectories of single molecules from sequential fluorescence images in the presence of photoblinking. The tracking algorithm is computationally nondemanding and does not assume a model for molecular motion, which allows one to determine correct trajectories even when a distribution of movement speeds is present. We applied the developed procedure to the important problem of monitoring surface motion of single molecules under ambient conditions. By limiting the laser exposure using sample scanning confocal microscopy, long-time trajectories have been extracted without the use of oxygen scavengers for single fluorescent molecules. Comparison of the experimental results to simulations showed that the smallest diffusion constants extracted from the trajectories are limited by detector shot noise giving error in locating the positions of the individual molecules. The simulations together with the single molecule trajectories and distributions of diffusion constants allowed us therefore to distinguish between mobile and immobile molecules. Because the analysis algorithm only requires a time series of images, the procedure presented here can be used in conjunction with various imaging methodologies to study a wide range of diffusion processes. [ABSTRACT FROM AUTHOR]

The mechanism of movement of nanovehicles on nonconducting surfaces is elucidated by describing the synthesis and optical properties of five fluorescently tagged nanocars. The molecules are designed such that the arrangement of their molecular axles and p-carborane wheels relative to the chassis is conducive to the control of directionality in the motion of the nanovehicles.

The dependence of the solute order parameter on the solute molecular weight ([M.sub.n]) is described. The results have shown that the increasing number of defects for larger polymer weights have inherently limited the polarization anisotropy of the polymer solute.

The photophysics of the fluorescent probe Lucifer yellow CH is investigated using fluorescence spectroscopic and computational techniques. Photophysical investigation in solvent mixtures and in deuterated solvents clearly indicates the predominance of the solvent-mediated intramolecular proton transfer in the excited state of the fluorophore in protic solvents.