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Rutile-TiO2 microspheres were synthesized by the single-step hydrothermal method and were subsequently annealed in an argon environment at 200 °C, 400 °C, and 600 °C. The influence of annealing temperature on structural, optical, morphological, and humidity sensing performance of rutile-TiO2 microspheres was examined. As-synthesized and annealed rutile-TiO2 microspheres were characterized using different characterization techniques. SEM confirmed the spherical shape morphology of TiO2 microspheres. XRD confirmed the tetragonal structure and rutile phase of TiO2 microspheres. The rutile phase of TiO2 was also confirmed by Raman spectroscopy. No significant change in the bandgap has been observed in rutile-TiO2 with increased annealing temperature. The presence of various chemical groups in rutile-TiO2 microspheres was studied using FTIR spectroscopy. The Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analysis showed a decrease in surface area and pore volume and an increase in average pore radius with an increase in annealing temperature. The humidity sensing performance of TiO2 microspheres thin films deposited on interdigital electrodes (IDEs) was studied between 11 to 97% relative humidity (RH). The humidity sensor fabricated using rutile-TiO2 microspheres annealed at 600 °C showed excellent humidity sensing properties. The sensor has the highest sensitivity (~ 71.5%), fast response, and recovery time of ~ 11.1 s and ~ 0.8 s, respectively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, we report the effect of sulfur (S) substitution with selenium (Se) in CZTS nanocrystals prepared by hot injection method. The formation of kesterite-copper zinc tin sulfide (Cu2ZnSnS4, CZTS) and copper zinc tin selenide (Cu2ZnSnSe4, CZTSe) nanocrystals is confirmed by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM) analysis. The XRD, TEM and atomic force microscopy (AFM) analysis shows an overall increase in average crystallite size upon Se substitution. AFM images revealed an increase in root mean square surface roughness (Sq) and average surface roughness (Sa) when S in CZTS is replaced by Se. The substitution of S by Se in host CZTS narrows the optical band gap from 1.56 to 1.03 eV. The ultraviolet photoelectron spectroscopy (UPS) analysis shows shift in valence band and conduction band edge in CZTSe compared to CZTS. The photocurrent density measurement in synthesized CZTSe thin films is ~ 4 to 5 times higher than CZTS thin films. The obtained results show that CZTSe can be a promising candidate as absorber material in photovoltaic applications. [ABSTRACT FROM AUTHOR]

According to the World Health Organization 2011 fact sheet, about 346 million people worldwide have diabetes. Lower glycemic index ( GI) and high-dietary foods are recommended especially for diabetic patients. In the present article, efforts were made to study the effect of various levels of powdered fruit by-products viz., apple pomaces, papaya peels and watermelon rinds on GI value of thepla ( Indian unleavened vegetable flat bread). The powdered fruit by-products mentioned earlier were then added in whole-wheat flour from 3, 6 to 9% on w/w basis along with spices and prepared into thepla dough. Thepla dough was evaluated for dough stickiness, work of adhesion and dough strength. Control thepla and other samples were evaluated for GI and sensory analysis. From the present study, it was observed that control thepla had 68.1 GI values where as with the addition of apple pomaces (9%), papaya peels (9%) and watermelon rinds (3%), GI significantly lowered to 63.38, 55.24 and 55.29, respectively. Practical Applications Thepla is an Indian unleavened flatbread made from whole-wheat flour with added spices and vegetables. Thepla has good taste and a high nutritive value (high fiber, low GI); hence, it is very popular among the population of the western part of India. Considering the importance of thepla, it was taken for the development of a hypoglycemic product by adding various fruit by-products. India is fast becoming a capital country of diabetic patients. Therefore, the demand for hypoglycemic products is very high. This research work explores the benefits of powedered fruit by-products for improvement of thepla qualities. The popularity of thepla in India as well as of the added functional ingredients, makes it a nutritious and commercially important product. [ABSTRACT FROM AUTHOR]

Hydrogen production via photoelectrochemical water splitting is a promising route to convert solar energy into chemical fuel, reducing energy crises and boosting environmental health. Here, we report the fabrication of ternary ZnO/CuO/Au heterostructures by electrodeposition and chemical bath deposition methods. The heterojunction formed can enhance the optical absorption, and photogenerated electrons and holes can efficiently separate due to the built-in electric field, which reduces recombination losses. Au plasmons incorporated in ZnO/CuO heterojunction enhance the optical absorption and promote fast free charge carrier transport at the interface through the surface plasmon resonance (SPR) effect. The ZnO/CuO/Au photoanode exhibits a photocurrent density of 1.08 mA/cm2 at 1.6 V Vs RHE, two times higher than pristine ZnO. The ZnO/CuO/Au photoanode exhibits the lowest charge transfer resistance of 600 Ω from electrochemical impedance spectra(EIS). The Bode plot revealed that the most extended lifetime of 8.69 μs is observed for ZnO/CuO/Au photoanode, which is larger than pristine ZnO. The synthesized thin films showed good stability and reusability for the photooxidation of water. • Fabrication of ternary ZnO/CuO/Au heterostructures by electrodeposition and chemical bath deposition methods. • Enhancement of optical absorption and reduction in recombination losses due to heterojunction. • Au plasmons incorporated in ZnO/CuO heterojunction enhances the optical absorption. • Au plasmons promote fast charge carrier transport at interface via surface plasmon resonance (SPR) effect. • ZnO/CuO/Au photoanode exhibits photocurrent density ∼ 1.08 mA/cm2, higher than pristine ZnO. [ABSTRACT FROM AUTHOR]

A promising method for producing hydrogen from solar energy and transforming it into chemical fuel is photoelectrochemical (PEC) water splitting. This ecologically friendly process can also avoid energy crises. Herein, we present the electrodeposition and chemical bath deposition methods used to create ZnO-nanorod/CdS nanoparticle (ZnO/CdS) heterostructures. The structural, optical, morphological, and PEC properties are investigated. UV–Visible spectroscopy analysis reveals the ZnO/CdS films have absorption edges in the visible and ultraviolet regions. The CdS loading directly impacts the PEC result of ZnO/CdS photoanodes. The M-S plots show a positive slope, indicating the n-type nature of ZnO and CdS. Under illumination intensity of 100 mW cm−2, the ideal photocurrent density reaches 4.90 mA/cm2 at a bias of 1.35 V versus reversible hydrogen electrode (vs. RHE) and is five times greater than the pristine ZnO nanorods. The maximum applied bias photon to the current conversion efficiency of 0.23 % at 0.26 V vs. RHE is observed in the pristine ZnO photoanodes. In contrast, the ZnO/CdS photoanode has achieved 3.02 % at 0.26 V vs. RHE, almost 13 times greater than the pristine ZnO photoanode. Finally, the hydrogen evolution process and the mechanism of charge transfer in ZnO/CdS heterostructure are discussed. • ZnO/CdS fabrication by electrodeposition and chemical bath deposition. • Efficient photoelectrochemical water splitting by ZnO/CdS. • The Mott-Schottky analysis revealed p-n junction formation. • Photocurrent density up to 4.90 mA/cm2 at 1.35 V vs. RHE under 100 mW/cm2 illumination. • Applied bias photon to current conversion efficiency of 3.02 % at 0.26 V vs. RHE. [ABSTRACT FROM AUTHOR]

In this study, high-quality γ-In 2 Se 3 thin films were successfully deposited on p-Si substrates via the RF sputtering technique. Structural characterization using XRD and Raman spectroscopy confirmed the formation of the hexagonal γ-phase of In 2 Se 3 film. FESEM analysis revealed the presence of small, homogeneous, and well-defined grains in the prepared γ-In 2 Se 3 film. EDS analysis confirmed the stoichiometric composition (∼ 2:3) of the In 2 Se 3 films. XPS further validated the presence of In, Se, and Si elements in the deposited films. Band gap analysis using UV-visible spectroscopy yielded a value of 1.96 eV for the γ-In 2 Se 3 film. Integration of γ-In 2 Se 3 with p-type Si enhanced photoresponsivity of 47.9 mA/W, photosensitivity of 282, and photo detectivity of 8.45 × 10 10 Jones. The self-powered γ-In 2 Se 3 /p-Si heterojunction-based photodetector exhibited rapid rise time attributed to the type II band alignment structure, facilitating efficient electron-hole pair separation and minimizing recombination. Furthermore, humidity and light intensity-dependent photodetector properties of γ-In 2 Se 3 /p-Si heterojunction photodetector were also investigated. An increase in photocurrent from 271 to 291 µA was observed with rising humidity levels, indicating the device's sensitivity to humidity variations. Furthermore, light intensity dependence studies revealed a linear relationship between photocurrent and incident light intensity, demonstrating the device's reliable response across various illumination levels.

Lead-free double perovskites (DPs) will emerge as viable and environmentally safe substitutes for Pb-halide perovskites, demonstrating stability and nontoxicity if their optoelectronic property is greatly improved. Doping has been experimentally validated as a powerful tool for enhancing optoelectronic properties and concurrently reducing the defect state density in DP materials. Fundamental understanding of the optical properties of DPs, particularly the self-trapped exciton (STEs) dynamics, plays a critical role in a range of optoelectronic applications. Our study investigates how Fe doping influences the structural and optical properties of Cs 2 AgBiCl 6 DPs by understanding their STEs dynamics, which is currently lacking in the literature. A combined experimental-computational approach is employed to investigate the optoelectronic properties of pure and doped Cs 2 AgBiCl 6 (Fe-Cs 2 AgBiCl 6 ) perovskites. Successful incorporation of Fe 3+ ions is confirmed by X-ray diffraction and Raman spectroscopy. Moreover, the Fe-Cs 2 AgBiCl 6 DPs exhibit strong absorption from below 400 nm up to 700 nm, indicating sub-band gap state transitions originating from surface defects. Photoluminescence (PL) analysis demonstrates a significant enhancement in the PL intensity, attributed to an increased radiative recombination rate and higher STE density. The radiative kinetics and average lifetime are investigated by the time-resolved PL (TRPL) method; in addition, temperature-dependent PL measurements provide valuable insights into activation energy and exciton-phonon coupling strength. Our findings will not only deepen our understanding of charge carrier dynamics associated with STEs but also pave the way for the design of some promising perovskite materials for use in optoelectronics and photocatalysis., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Cu 2 ZnSnS 4 (CZTS) thin films have attracted considerable attention as potential candidates for photovoltaic absorber materials. In a vacuum deposition technique, a sputtering stacked metallic layer followed by a thermal process for sulfur incorporation is used to obtain high-quality CZTS thin films. In this work, for fabricating CZTS thin films, we have done a 3LYS (3 layers), 6LYS, and 9LYS sequential deposition of Sn/ZnS/Cu metal stack ( via . metallic stacked nanolayer precursors) onto Mo-coated corning glass substrate via . RF-sputtering. The prepared thin films were sulfurized in a tubular furnace at 550 °C in a gas mixture of 5% H 2 S + 95% Ar for 10 min. We further investigated the impact of the Sn/ZnS/Cu metal stacking layers on the quality of the thin film based on its response to light because metal inter-diffusion during sulfurization is unavoidable. The inter-diffusion of precursors is low in a 3-layer stack sample, limiting the fabricated film's performance. CZTS films with 6-layer and 9-layer stacks result in an improved photocurrent density of ∼38 μA cm -2 and ∼82 μA cm -2 , respectively, compared to a 3-layer sample which has a photocurrent density of ∼19 μA cm -2 . This enhancement can be attributed to the 9-layer approach's superior inter-diffusion of metallic precursors and compact, smooth CZTS microstructure evolution., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Layered bismuth triiodide (BiI 3 ) is a 2D material that has emerged as an ideal choice for optical sensors. Although BiI 3 has been prepared using vacuum-based deposition techniques, there is a dearth of research studies on synthesizing this material using chemical route. The present work uses a facile spin coating method with varying rotation speeds (rpm) to fabricate BiI 3 material thin films for photodetection applications. The structural, optical, and morphological study of BiI 3 thin films prepared at 3000-6000 rpm were investigated. XRD analysis indicates formation of BiI 3 films and revealed that BiI 3 has a rhombohedral crystal structure. FESEM analysis showed that BiI 3 films prepared at different rpm are homogeneous, dense, and free from cracks, flaws, and protrusions. In addition, films show an island-like morphology with grain boundaries having different grain sizes, micro gaps, and the evolution of the granular morphology of BiI 3 particles. The UV spectroscopy and photoluminescence analysis revealed that BiI 3 films strongly absorb light in the visible region of spectra with a high absorption coefficient of ∼10 4 cm -1 , have an optical band gap of ∼1.51 eV. A photodetector was realised using fabricated BiI 3 film obtained at an optimum spin speed of 4000 rpm. It showed rapid rise and decay times of 0.4 s and 0.5 s, a responsivity of ∼100 μA W -1 , external quantum efficiency of 2.1 × 10 -4 %, and detectivity of ∼3.69 × 10 6 Jones at a bias voltage of 0 V. Our results point towards a new direction for layered 2D BiI 3 materials for the application in self-biased photodetectors., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

ZrBi 2 Se 6 nanoflower-like morphology was successfully prepared using a solvothermal method, followed by a quenching process for photoelectrochemical water splitting applications. The formation of ZrBi 2 Se 6 was confirmed by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The estimated value of work function and band gap were found to be 5.5 and 2.26 eV measured using diffuse reflection spectroscopy and ultraviolet photoelectron spectroscopy, suggesting the potential candidate for water splitting. The highest current density of 9.7 μA/cm 2 has been observed for the ZrBi 2 Se 6 photoanode for the applied potential of 0.5 V vs SCE. The flat-band potential value was -0.46 V, and the 1.85 nm width of the depletion region is estimated from the Mott-Schottky (MS) analysis. It also reveals that the charge carrier density for the ZrBi 2 Se 6 nanoflowers is 4.8 × 10 15 cm -3 . The negative slope of the MS plot indicates that ZrBi 2 Se 6 is a p-type semiconductor. It was observed that ZrBi 2 Se 6 nanoflowers had a high charge transfer resistance of ∼730 kΩ and equivalent capacitance of ∼40 nF calculated using electrochemical impedance spectroscopy (EIS) measurements. Using chronoamperometry, the estimated rise time and decay time were 50 ms and 0.25 s, respectively, which reveals the fast photocurrent response and excellent PEC performance of the ZrBi 2 Se 6 photoanode. Furthermore, an attempt has been made to explain the PEC activity of ZrBi 2 Se 6 nanoflowers using an energy band diagram. Thus, the initial results on ZrBi 2 Se 6 nanoflowers appear promising for the PEC activity toward water splitting., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)