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Indium selenide (γ-In2Se3) films were prepared using RF magnetron sputtering. Influence of deposition time on structural, optical, morphological, and photoelectrochemical (PEC) performance was studied. Formation of γ-In2Se3 is confirmed by low angle XRD, Raman spectroscopy, and XPS analysis. Surface morphology investigated using FE-SEM shows that γ-In2Se3 films are uniform and have a dense grain structure, without cracks and holes. Optical properties show that γ-In2Se3films absorb mainly in the UV region, and the bandgap energy decreases from 2.81 to 2.27 eV as deposition duration increases. Conduction and valance band-edge potential values show that γ-In2Se3 films are suitable for photoelectrochemical hydrogen evolution. PEC activity of γ-In2Se3 photoanodes was evaluated using linear sweep voltammetry (LSV), and there was an increase in photocurrent density with deposition time. Electron impedance spectroscopy (EIS) analysis revealed that γ-In2Se3 photoanodes had high charge transfer resistance, and it decreases with deposition time, which leads to improved PEC performance. Investigation of Mott Schottky's (MS) results shows a shifting of flat band potential towards negative potential, suggesting movement of fermi level towards conduction band edge. Carrier density increases from 3.7 × 1019 cm−3 to 8.9 × 1020 cm−3 and depletion layer width of γ-In2Se3 photoanodes are found in the range of ~ 2.67–9.10 nm. The gradual increase in electron lifetime indicates a decrease in the recombination rate of photo-generated charge carriers. An increase in time-dependent photocurrent density reveals that γ-In2Se3 films have effective electron–hole separation. Our work demonstrates that γ-In2Se3 can be a probable candidate for PEC water splitting and opto-electronic applications.

In this paper, Au plasmons and their synergistic effects with ZnO nanorods (ZNs) have been investigated for photoelectrochemical (PEC) water splitting application. Au plasmons and ZNs are deposited electrochemically. Au modified nanostructures have absorption in the visible region as plasmons enhance charge transfer and inhibit charge recombination. ZNs modified with Au (deposition duration ∼ 60 s) has a photo-current density of ∼ 660 µA cm-2, at a bias of 1.0V/SCE. X-ray diffraction and scanning electron microscopy were used to study the structure and surface morphology of fabricated photoanodes. UV-Visible absorption and Photoluminescence spectroscopy were used for optical characterization. We have recorded current-voltage measurements and photo-conversion efficiency measurements to substantiate our observations of the synthesized photoanodes for prospective application in PEC splitting of water. We have also carried out Mott-Schottky, and electrochemical impedance spectroscopy analysis. The analysis reveals that Au modified ZNs based photoanodes are a better proposition than their bare counterparts for PEC water splitting application.

In present study, CZTS films were fabricated using 2 different processes and their properties have been compared. The first is a 2-stage process which includes deposition of CZT followed by sulfurization and the second is a 3-stage process which includes deposition of identical CZT, soft annealing (pre-heating) and sulfurization. Structural, morphological, optical and compositional properties of CZTS films are investigated by XRD, Raman spectroscopy, FE-SEM, UV–Visible spectroscopy, EDS and photoresponse measurements. Structural analysis revealed that films prepared by both processes have polycrystalline kesterite-CZTS structure and exhibit prefered orientation along (1 1 2) direction. It has been observed that soft annealing temperature in 3-stage process significantly improve the crystal quality of CZTS films. Surface morphology of films sulfurized at 550 °C shows a uniform and compact micrograin (∼0.31 µm) without cracks. The soft annealing temperature significantly improves micrograin size (∼0.49 µm) and compactness of CZTS films. UV–Visible spectroscopy showed that the band gap of all CZTS films is in optimal range. The CZTS films fabricated by 3-stage process, exhibits high photocurrent response under intermittent visible-light irradiation, implying that they can useful as an absorber layer in solar cells.

Diabetes afflicts upwards of 425 million people globally with 80% of that number living in the developing world. The World Health Organization has declared diabetes a global health threat. Here, we describe a Community Theater (CT) project implemented in Fiji, a nation where 30% of the adult population is diabetic. Current diabetes education methods used by the Ministry of Health in Fiji have proven to be ineffective in stemming the growing incidence of the disease. Our research hypothesis was that significant improvements would occur from baseline in the physical and psychosocial markers among a group of outpatients being treated at a diabetic clinic who were exposed to CT interventions over a 23-month period. Significant improvement in HbA1c levels occurred in the intervention group compared to a control group that was not exposed to CT. We conclude that novel educational approaches are needed, including CT, to combat the growing epidemic of diabetes that threatens Fiji and all other Pacific Island nations.

The influence of Ag plasmons and reduced graphene oxide (RGO) on ZnO nanorods (Z-NRs)-based photoanodes for photoelectrochemical splitting of water is the main focus of the present experimental study. Plasmonic layer of Ag is incorporated either as a base (Ag-Z-NRs) layer or as a top layer (Z-NRs-Ag) in an electrochemically deposited Z-NRs-based photoanodes. Z-NRs-Ag photoanodes exhibited better optical absorption as plasmonic layer stimulates charge transfer and restrain charge recombination. It had shown the photocurrent density of ~0.79 mA cm−2, at a bias of 1.4 V/RHE. A mediator layer of RGO when introduced in Z-NRs-Ag photoanodes synergistically with Ag plasmons enhances the photocurrent density to ~1.3 mA cm−2 at a bias of 1.4 V/RHE. Structure and surface morphology of the synthesized photoanodes was studied using x-ray diffraction and field emission scanning electron microscopy. Elemental analysis and optical characterization was done using energy-dispersive x-ray analysis, UV–Visible absorption spectroscopy and Raman spectroscopy. The current–voltage characteristics, electrochemical impedance spectroscopy, Mott–Schottky analysis, photoconversion efficiency and incident photon to current conversion efficiency measurements have been used to substantiate our observations of synthesized photoanodes.

We report synthesis and use of Chlorophyll‐a/ZnO nanorod based hybrid photoanodes for photoelectrohemical (PEC) activity. Hybrid photoanodes consist of vertically oriented self ordered nanorod array of ZnO fabricated via electrodeposition followed by sensitization with chlorophyll‐a. Under AM 1.5 illumination (100 W/cm2), at 0.75 V bias, the hybrid photoanodes achieved a photocurrent density of 0.67 mA/cm2 which is ∼2.6 times increase over bare ZnO nanorods (0.26 mA/cm2). To the best of our knowledge, this is the first report on the use of Chlorophyll‐a/ZnO nanorod based hybrid electrodes in photoelectrochemical cells, with potential applications in switching and sensing.

Carbon functionalized bismuth vanadate (BVO) photoanodes were synthesized using simple wet chemical process. To ascertain and determine various aspects of synthesized photoanodes, different types of characterization and measurements such as, X-ray Diffraction (XRD), Field emission scanning electron microscope (FE-SEM), UV–Visible (UV–Vis), Raman, Photoelectrochemical (PEC), Mott-Schottky (MS), and Electron Impedance Spectroscopy (EIS) have been carried out. Carbon functionalized BVO (C-BVO) photoanodes demonstrated superior photoconversion efficiency (η∼0.38%) and short circuit current (JSC∼0.50 mA/cm2 at 0.5 V vs. SCE) compared to pristine BVO. Bare BVO based PEC OR and AND logic gates have also been designed using pulsed white light beams. The PEC response reveals that for a white light beam with peak pump intensity of 100 mW/cm2, a photocurrent density of 83 μA/cm2 is generated at a bias of ∼0.5 V vs. SCE. Moreover, by tuning bias the photocurrent response can be inverted and further utilized to realize different logic operations simultaneously. The present study paves a new way for bismuth vanadate-based PEC computing devices.

The present work represents successful synthesis of CdTe-sensitized TiO2 nanoarray thin films by two simple chemical routes. Here, we report the sensitization of TiO2 nanoarrays with CdTe nanoparticles through the electrodeposition technique at ambient condition. The electrodeposition of 30 min leads to the formation of shell of CdTe nanoparticles over TiO2 nanoarrays. This core-shell formation structure was further confirmed by TEM and HR-TEM analysis. Optical absorption and photoelectrochemical study revealed that the TiO2/CdTe core-shell heterostructure extend the absorption edge of titania in the visible region of solar spectrum; it also facilitates the efficient charge transport and reduces the recombination losses. The maximum photoconversion efficiency of 0.32% is obtained for TiO2/CdTe core-shell semiconductor-sensitized solar cells (SSSCs).

Mucopolysaccharidosis VII (MPS VII) is a recessively inherited lysosomal storage disorder caused by β-glucuronidase enzyme deficiency. The disease is characterized by widespread accumulation of non-degraded or partially degraded glycosaminoglycans, leading to cellular and multiple tissue dysfunctions. The patients exhibit diverse clinical symptoms, and eventually succumb to premature death. The only possible remedy is the recently approved enzyme replacement therapy, which is an expensive, invasive and lifelong treatment procedure. Small-molecule therapeutics for MPS VII have so far remained elusive primarily due to lack of molecular insights into the disease pathogenesis and unavailability of a suitable animal model that can be used for rapid drug screening. To address these issues, we developed a Drosophila model of MPS VII by knocking out the CG2135 gene, the fly β-glucuronidase orthologue. The CG2135−/− fly recapitulated cardinal features of MPS VII, such as reduced lifespan, progressive motor impairment and neuropathological abnormalities. Loss of dopaminergic neurons and muscle degeneration due to extensive apoptosis was implicated as the basis of locomotor deficit in this fly. Such hitherto unknown mechanistic links have considerably advanced our understanding of the MPS VII pathophysiology and warrant leveraging this genetically tractable model for deeper enquiry about the disease progression. We were also prompted to test whether phenotypic abnormalities in the CG2135−/− fly can be attenuated by resveratrol, a natural polyphenol with potential health benefits. Indeed, resveratrol treatment significantly ameliorated neuromuscular pathology and restored normal motor function in the CG2135−/− fly. This intriguing finding merits further preclinical studies for developing an alternative therapy for MPS VII. This article has an associated First Person interview with the first author of the paper., Summary: The authors generate a new Drosophila model of MPS VII, which offers insights into the pathophysiology of this disease, and also uncovers the therapeutic potential of resveratrol in treating MPS VII.

We present designs of optoelectronic OR, AND, NOR, and NAND logic gates with multiple pulsed pump laser beams based on the photovoltaic response of bacteriorhodopsin (BR) molecules embedded in a polyvinyl matrix coated on ITO. A detailed experimental study of the photovoltaic response reveals that continuous pulsed exposure to 532 nm and 405 nm laser light results in a large photocurrent/photovoltage, due to rapid reprotonation and chromophore reisomerization, taking BR to the ground state in hundreds of nanoseconds. It also helps in sustaining the photovoltage at higher frequencies and in maintaining the shape of the photovoltage. It is shown experimentally that for a pulsed laser beam at 532 nm with peak pump intensity of 1.19 W/cm (2), a photovoltage of 50 mV is generated. A detailed numerical simulation of the photovoltaic response of BR has been carried out taking into account all the six states (B, K, L, M, N, and O) in the BR photocycle to ascertain the effect of various parameters such as lifetime of the M-state, the pump pulse-width, pump intensity, lifetime of excited protons, and rate constant of excited protons. Experimental results are in good agreement with theoretical simulations. The present study opens up new prospects for protein-based optoelectronic computing.

We analyze all-optical switching in chlorophyll-A (Chl-A) molecules for different combinations of pump-probe wavelengths, based on nonlinear intensity-induced excited-state absorption. It is shown that for a pulsed pump beam at 672 nm with peak pump intensity of 5 kW/cm(2) and Chl-A concentration of 1.5 mM, the transmission of a continuous-wave probe beam at 476 nm can be completely switched off (100% modulation) with switch on-off time of 0.58 and 0.18 micros, respectively. It is also shown that the switching characteristics can be inverted by changing the probe beam wavelength. The effect of various parameters, such as concentration, pump beam intensity, pump pulse width, absorption cross section of the ground state, and lifetimes of different states, on the switching characteristics has been analyzed in detail. It is shown that there exists an optimum value of concentration of Chl-A for maximum switching contrast, for the case when the ground state also absorbs the probe beam. The switching characteristics of Chl-A have also been compared with Chl-B and Bchl. Experimental results for all-optical switching in Chl-A with a train of pulses are in good agreement with theoretical results. It is shown that higher contrast and faster switching can be achieved as opposed to what was reported recently in other biomolecules such as archael rhodopsin and phototropin proteins. The results have also been used to design switches and logic gates.

We present a theoretical design of an all-optical reconfigurable logic unit based on optically controlled microcavity switches, for realization of all-optical computing circuits. It can execute different logic and arithmetic operations such as half and full adder or subtractor, by only changing the control inputs on the same circuit. Theoretical designs considering bacteriorhodopsin (BR) protein coated microcavities in tree architecture have been presented. The combined advantages of high Q-factor, tunability, compactness, switching of near-IR signals at telecom wavelengths (1310/1550 nm) with low-power control signals, and flexibility of cascading switches to form circuits, makes the designs promising for practical applications. They combine the ultrahigh sensitivity of both BR and microresonators to define a novel paradigm of all-optical computing based on hybrid nanobiophotonic integration.

We propose an all-optical reconfigurable logic unit based on optically controlled microcavity switches that can execute different logic and arithmetic operations on the same hardware with different configuration. Theoretical designs considering bacteriorhodopsin protein-coated microcavities in a tree architecture have been presented. The combined advantages of high Q-factor, tunability, compactness, low-power control signals and flexibility of cascading switches to form circuits, makes the designs promising for practical applications.

We present designs of all-optical MUX/DEMUX and half-adder/subtractor circuits based on switching of an infrared laser beam at 1310 nm in bacteriorhodopsin protein coated silica microsphere using low power (

We present a design of the conservative, reversible, and universal all-optical Fredkin logic gate based on a single bacteriorhodopsin (BR)-protein-coated silica microcavity. The switching of a near-IR laser beam at 1310 or 1550 nm by photoactivating a silica microsphere coated with BR monolayers with a low power control signal at 532 nm, in contact between two tapered single-mode fibers, is used as a template for a four-port tunable resonant coupler Fredkin gate. The proposed gate has also been used to design low-power all-optical AND, OR, NOT, XOR, and X-NOR gates and full-adder and demultiplexer/multiplexer circuits. The advantages of high Q-factor, tunability, compactness, low-power control signals, high fan-out, and flexibility of cascading switches in 2-D to 3-D architectures to form circuits, makes the designs promising for practical applications. The proposed design provides a new paradigm for hybrid nanobiophotonic integration for all-optical computing.

We show all-optical switching of an input infrared laser beam at 1310 nm by controlling the photoinduced retinal isomerization to tune the resonances in a silica microsphere coated with three bacteriorhodopsin (BR) protein monolayers. The all-optical tunable resonant coupler re-routes the infrared beam between two tapered fibers in 50 μs using a low power (

We theoretically analyze all-optical switching in the Phototropin mutant LOV2-C250S of the LOV2 domain from Chlamydomonas reinhardtii phot protein, based on nonlinear intensity-induced excited-state absorption. The transmission of a cw probe laser beam at 715 nm corresponding to the peak absorption of the first excited L-state, through the LOV2 sample, is switched by a pulsed pump laser beam at 442 nm that corresponds to the maximum initial D state absorption. The switching characteristics have been analyzed using the rate equation approach, considering the two intermediate states and transitions in the LOV2 photocycle. We report a comparative study of the switching response of this genetically modified protein-mutant LOV2-C250S with the wild-type LOV2 and present designs for all-optical logic gates. The switch-off and on time is 3.1 and 28.58 µs. All-optical switching in this mutant is faster than the wild-type. It shows the possibility of optimizing the photoresponse by genetic engineering for faster all-optical biomolecular computing.