Defect-rich CMO NF membrane deliver broadband light absorption, enhanced hydrophilicity, and efficient photothermal conversion. It maintains structural stability and effectively purifies saline and dye-contaminated water.

The growing global demand for freshwater and sustainable energy requires integrated technologies capable of addressing water-energy challenges in a single platform. Here, a multifunctional photothermal architecture is developed by integrating copper bismuth oxide (CuBi2O4; CBO) with a two-dimensional (2D) Ti3C2-F MXene (MX) to form a CBO@MX hybrid, enabling simultaneous solar desalination, electrokinetic energy generation, and salt harvesting. CBO@MX loaded onto a cellulose membrane, is designed to promote directional capillary flow, ensuring sustained saline water supply to the photothermal interface. Synergistic coupling between the semiconducting CBO and MX enables broadband light absorption and efficient conversion into heat, while interlocking nanochannels facilitate ion transport and electrokinetic potential generation through the formation of an electric double layer. Under AM 1.5G solar irradiation, the CBO@MX delivered a high evaporation rate of ∼1.68 kg m-2 h-1 and simultaneously produced a stable open-circuit voltage of ∼0.5 V without any external power input. Moreover, asymmetrical wettability induced self-driven saline water transport and controlled salt crystallization at the membrane periphery, effectively mitigating pore blockage, while enabling simultaneous salt harvesting. The CBO@MX hybrid membrane exhibited stable performance for twenty five consecutive desalination cycles. This study presents a scalable, low-cost, and sustainable strategy for integrating solar-driven desalination with energy harvesting, offering a promising route toward decentralized and off-grid water-energy nexus technologies.

Addressing global water scarcity and pollution requires the development of innovative, multifunctional materials capable of simultaneously tackling multiple challenges. This study explores manganese ferrite (MnFeO3, MFO) nanoparticles synthesized via a co-precipitation method for their tri-functional performance in environmental remediation, clean water production, and energy generation. The MFO catalyst exhibits robust photocatalytic activity, achieving 98.99 % degradation of crystal violet (CV) dye and demonstrating efficacy against both cationic and anionic dyes. Furthermore, MFO-coated cellulose-based devices enable efficient interfacial solar steam generation (ISSG) from saline water of varying concentrations, indicating potential for clean water production. The MFO photothermal evaporator generated 47.6 degrees C temperature at the air/water interface and achieved evaporation rates of 2.28 kg/m(2)h under solar simulator and 1.6 kg/m(2)h under direct sunlight. Evaporation rates of similar to 1.89, similar to 1.58, and similar to 1.40 kg/m(2)h were obtained from 3.5, 7.0, and 10 wt % saline water, respectively. The MFO@cellulose evaporator maintained a surface temperature of similar to 65 degrees C in ambient air and exhibited stable rejection performance over 5 ISSG cycles for 3.5 wt % salt water. Beyond water remediation, MFO also demonstrates potential in hydro-voltaic electricity generation, producing an open-circuit voltage of 0.7 V for 10 devices connected in series through electro-kinetic processes under natural sunlight. This integrated approach underscores the versatility of MFO and presents a promising route for sustainable water treatment and renewable energy generation, particularly suitable for deployment in resource-limited surroundings.

Organometallic halide perovskites have shown immense potential for light harvesting and visible light sensing applications. Large CH3NH3PbBr3 single crystals (SC) of size 4 x 3.5 mm(2) have been synthesized using a simple inverse temperature crystallization route. The X-ray diffraction spectra confirm the formation of a single crystalline phase without any impurity. UV-vis diffuse reflectance spectra show an optical band gap of similar to 2.28 eV, which is suitable for visible light sensing. Thereafter, the device with architecture Ag/CH3NH3PbBr3 SC/Ni was fabricated by thermally depositing the nickel (Ni) and silver (Ag) metal on either side of the SC and was used for visible light sensing applications. The device exhibits a photocurrent of similar to 3 mu Acm(-2) at a forward biasing of 5 V with responsivity (R) similar to 14 mAW-1 and detectivity (D*) similar to 5 x 10(7) Jones. Furthermore, the device is subjected to an external magnetic field (B vector) varying from 0 to 100 mT to analyze the effect of the B vector on device performance. The device shows similar to 28% increment in the photocurrent at B vector of 30 mT with significantly higher R and D* of similar to 37 mAW-1 and similar to 2 x 10(8) Jones, respectively, which is due to enhanced charge carrier transportation and lower recombination at the Ni/SC interface under the influence of external magnetic field. The present work provides a practicable strategy to tune photocurrent by an external B vector and further pave the way toward multifunctional optoelectronic devices.

Photothermal Ni-doped LaFeO3 (NLFO) (LaFe1-xNixO3, x = 0, 0.2, 0.3, 0.4, and 0.5) microspheres composed of nanoparticles synthesized by hydrothermal method are utilized for interfacial solar steam generation (ISSG) of salty and contaminated water. The orthorhombic (pnma) to rhombohedral (R3 c) phase transition of LaFeO3 (LFO) at morphotropic phase boundary (MPB) flattens the free energy profile, and high absorbance in the 800-2000 nm Vis-NIR region arises due to the creation of intra-band gap states are accountable for superior activity towards the ISSG for desalination. The La, Ni, and Fe possess the oxidation states of 3+, 2+, and 3+/4+, respectively, showing successful doping of Ni2+ at the Fe3+ sites that produce lattice distortion at La/FeO6 octahedra. LaFe0.5Ni0.5O3 (NLFO5) sample exhibits surface temperature of 50.4 degrees C due to heat localization and produces evaporation flux of 2.89 kg/m(2)h under IR illumination at the air-water interface. Importantly, NLFO5 loaded cellulose paper shows good repeatability and cyclic stability for 10 consecutive cycles under IR illumination and equivalent evaporation flux of 2.4 kg/m(2)h under direct sunlight illumination. Moreover, 3.5 wt% saline water shows a drastic decrement in ion concentration after ISSG, as confirmed by atomic absorption spectroscopy. Furthermore, NLFO5 possesses good evaporation flux of 2.27 and 2.20 kg/m(2)h for water contaminated with RhB and MB organic dye. Our results propose the NLFO as distinguished photothermal material for ISSG application and wastewater purification by means of evaporation.

Recently, the efficiency of single‐junction perovskite solar cells has been competing with the crystalline Si solar cells. However, the perovskite absorbers are toxic and susceptible to moisture. Herein, the performance of an environmentally benign and durable Cs2BiAgI6 light harvester using the 1D Solar Cell Capacitance Simulator (SCAPS‐1D) software package is evaluated. The primary physical parameters, namely, defect and doping densities and thickness of the subsequent layers, are varied to achieve high efficiencies. The optimized Cs2BiAgI6‐based double perovskite solar cells with three distinct hole‐transporting layers (HTLs) (i.e., MoO3, CuSCN, and spiro‐OMeTAD) deliver a power conversion efficiency of ≈29% with AZnO as electron transport layer (ETL). Further, a variety of possible rear electrodes are explored, and their effect on the performance is estimated. For real‐time examination of the Cs2BiAgI6‐based double perovskite solar cells, the variation of power conversion efficiency (PCE) concerning the operating temperature is estimated. The thickness of the Cs2BiAgI6 light harvester layer and the bulk defect density are the key aspects in attaining high power conversion efficiencies in Cs2BiAgI6‐based double perovskite solar cells.

The CuBi2O4 (CBO) microspheres comprising 1D nanostructures crystallized in a tetragonal crystal system with P4/ncc space group. The Cu and Bi ions in the CBO photothermal harvesters remained in stoichiometric 2+ and 3+ oxidation states, respectively. The CBO showed excellent absorption in the entire ultra-violet (UV) and visible spectrum, covering the prominent solar spectrum. The CBO microsphere formed by assembling 1D CBO nanorods possessed a specific surface area of 1.45 m2/g, and the temperature-dependent contact angle of water over CBO surface decreases upon increasing temperature, making it an excellent choice in solar steam generation (SSG) process. Thus, the presence of CBO-loaded cellulose paper at the air-water interface has demonstrated three times accelerated evaporation rate of 1.7 kg/m2h. Notably, the CBO-loaded cellulose paper delivered high stability with no change in evaporation rate even after consecutive cycles. The CBO exposed to the natural sunlight in the customized desalination setup provided >50 % CR/ER ratio for the salinity of 3.5, 10, and 20 wt % salty waters. Our findings establish that CBO is a highly desirable photo-material for SSG and has the potential to act as a solar light harvester for photovoltaic systems.

Besides the perovskite light absorber, engineering of the charge transport layers plays a prominent role in synergistically enhancing the efficiency and stability of perovskite solar cells.

High-performance nonvolatile resistive random access memories (ReRAMs) and their small stimuli control are of immense interest for high-speed computation and big-data processing in the emerging Internet of Things (IoT) arena. Here, we examine the resistive switching (RS) behavior in growth-controlled HfO2/La0.67Sr0.33MnO3 (LSMO) heterostructures and their tunability in a low magnetic field. It is demonstrated that oxygen-deficient HfO2 films show bipolar switching with a high on/off ratio, stable retention, as well as good endurance owing to the orthorhombic-rich phase constitution and charge (de)trapping-enabled Schottky-type conduction. Most importantly, we have demonstrated that RS can be tuned by a very low externally applied magnetic field (∼0-30 mT). Remarkably, application of a magnetic field of 30 mT causes RS to be fully quenched and frozen in the high resistive state (HRS) even after the removal of the magnetic field. However, the quenched state could be resurrected by applying a higher bias voltage than the one for initial switching. This is argued to be a consequence of the electronically and ionically "active" nature of the HfO2-x/LSMO interface on both sides and its susceptibility to the electric and low magnetic field effects. This result could pave the way for new designs of interface-engineered high-performance oxitronic ReRAM devices.

Perovskite light absorbers have drawn attention worldwide for optoelectronic devices due to their solution-processable photovoltaic properties, high carrier mobility, broad spectral range, and integration with a wide range of substrates, etc. A facile NiO/CH3NH3PbI3 heterojunction was fabricated in an ambient environment for self-powered and high-performance photodetector (PD) application. The self-powered PD showed a high responsivity of 33.39 mA/W for UV light and 5.79 mA/W for white light at zero bias, which further increases up to 28.6 A/W for UV light and 29.2 A/W for white light at +1 V. Subsequently, the detectivity for an entire UV and visible spectrum was observed to be above 1010 Jones at zero bias. Interestingly, the stability study for PDs in the air up to 38 days revealed the highest photoresponsivity of 40.56 mA/W at zero bias. This enhancement is attributed to the intrinsic modification within metal halide perovskites that lead to optimized PbI2 content. Additionally, a systematic study of X-ray diffraction patterns at an interval of days revealed the presence of PbI2 content. Further, the photodetection ability was retained for up to 58 days with a decrease in light current without encapsulation. Our results indicate that a NiO/CH3NH3PbI3 heterojunction-based PD paves the way for ambient friendly, high-performance, self-powered, stable optoelectronic applications.

In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic (PV) performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After temperature-dependent grazing-incidence wide-angle X-ray scattering, in situ X-ray diffraction, and optical absorption experiments were carried out, the thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10% in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of the crystallinity and p doping in the hole transporter, spiro-OMeTAD, which promotes the efficient extraction of photogenerated carriers. However, further thermal cycles produced a detrimental effect on the PV performance of PSCs, with the short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the PV performance of PSCs degraded at high operation temperatures; both the short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of the fill factor was the opposite. Our impedance spectroscopy analysis revealed a monotonous increase of the charge-transfer resistance and a concurrent decrease of the charge-recombination resistance with increasing temperature, indicating a high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance because of the deteriorated interfacial photocarrier extraction. The present findings suggest that the development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite PVs in harsh thermal environments.

Schottky-junctions formed on hybrid perovskite CH3NH3PbBr3 single crystals show significant light-induced tuning of dielectric constant and self-biased photodetection.

An efficient self-powered photodetector design involving a C-Si hetero-interface with back-to-back MOS-Schottky (Pt-SiO2-Si-C-Pt) device action is presented. Pulsed laser deposition of a carbon thin film is used which dynamically removes the native surface oxide to form the desired Schottky interface. The combined device action yields two orders of magnitude photoresponse at zero bias.

We report on the ferroelectricity for morphotropic-phase-boundary lead (Pb) free 0.5BaTi0.8Zr0.2O3-0.5Ba0.7Ca0.3TiO3 (0.5BZT-0.5BCT) thin films. Thin films were grown on Pt/Ti/SiO2/Si substrate using pulsed laser deposition. Raman spectroscopic data combined with the X-ray diffraction analyses confirm body centered tetragonal crystallographic structure 0.5BZT-0.5 BCT thin films on Pt/Ti/SiO2/Si. Polarization studies demonstrate that these 0.5BZT-0.5BCT films exhibit a large remnant and saturation polarization of 37 μC/cm2 and 40 μC/cm2, respectively, with a coercive field of 140 kV/cm. A correlation between polarization dynamics, structural distortion, and phonon vibration is established. The splitting of X-ray diffraction peak of the thin film in the 2θ range of 44.5° to 46.5° represents high degree of tetragonality. The tetragonality factor calculated by Rietveld analysis was found to be 0.006 and can be a major cause for the increased remnant polarization value. It is established from Raman spectra that the non-centrosymmetricity due to the displacement of Ti/Zr ions from its octahedral position is related to the peak position as well as the broadening of the A1 (LO) optical phonon mode. This increase of broadness in the thin film causes an increase in the dipole moment of the unit cell and, hence, the net increase in polarization values.

We report field electron emission investigations on pulsed laser-deposited molybdenum disulfide (MoS2) thin films on W-tip and Si substrates. In both cases, under the chosen growth conditions, the dry process of pulsed laser deposition (PLD) is seen to render a dense nanostructured morphology of MoS2, which is important for local electric field enhancement in field emission application. In the case of the MoS2 film on silicon (Si), the turn-on field required to draw an emission current density of 10 μA/cm(2) is found to be 2.8 V/μm. Interestingly, the MoS2 film on a tungsten (W) tip emitter delivers a large emission current density of ∼30 mA/cm(2) at a relatively lower applied voltage of ∼3.8 kV. Thus, the PLD-MoS2 can be utilized for various field emission-based applications. We also report our results of photodiode-like behavior in (n- and p- type) Si/PLD-MoS2 heterostructures. Finally we show that MoS2 films deposited on flexible kapton substrate show a good photoresponse and recovery. Our investigations thus hold great promise for the development of PLD MoS2 films in application domains such as field emitters and heterostructures for novel nanoelectronic devices.

A composite of reduced graphene oxide (RGO) with oxides of manganese and cobalt together was prepared by a solvothermal method. During synthesis, both the reduction of graphene oxide as well as the growth of nanorod shaped CoMn2O4 and Co3O4 occurred simultaneously having a crystallite size of ~8 nm calculated from X-ray diffraction (XRD). The as-obtained triple nanocomposite material designated as RGO–MnCoO exhibited excellent activity for the liquid phase aerobic oxidation of aromatic alcohols under base-free conditions selectively giving the corresponding aldehydes (>85%). RGO loading was varied in the range of 1–10%, among which 1% RGO–MnCoO showed maximum catalytic activity enhancement of 24% as compared to the bare mixed oxide (MnCo-MO) for the oxidation of vanillyl alcohol. HR-TEM of RGO–MnCoO revealed that it was a composite material having uniform nanotubes of ~25 nm length and 6 nm diameter with a fringe pattern showing the (103) and (004) planes and lattice spaces of 0.26 nm and 0.22 nm, respectively, for the spinel CoMn2O4. The detailed studies on the morphology, size and composition of the as-prepared RGO–MnCoO nanocomposite by XRD, XPS, N2-adsorption/desorption and O2-TPD techniques were used to understand the role of RGO in the enhancement of catalytic activity for oxidation reaction.

A series of Bi1−x Ca x FeO3 (BCFO) nanoparticles (with x = 0.0, 0.03, 0.07, 0.10, 0.15, and 0.20) have been synthesized by sol–gel reaction. X-ray diffraction patterns establish the formation of hexagonal bismuth ferrite as the prominent phase, with a small contribution of the Bi2Fe4O9 phase (as reported by others as well) which diminishes rapidly with the increase in Ca concentration. Interestingly, above a calcium dopant concentration of about 10 % peaks of Fe2O3 (both α and γ components) are observed with a concomitant enhancement of ferromagnetism. Small contribution of the Bi6Ca4O13 phase is also noted in these samples. This phase evolution is driven by dopant-induced strain energy and increasing oxygen vacancy concentration for local charge balance. Transmission electron microscopy (with elemental scanning) and Mössbauer spectroscopy techniques bring out the evolution of nanoparticle morphology (and elemental distribution) and phase configuration, respectively. Measurements of photocatalytic activity (and photo-Fenton activity with H2O2) reveal that Ca doping at the Bi site in BFO enhances the activity significantly in the concentration regime where BFO/α(γ)-Fe2O3 phases coexist in the form of a nanocomposite. The enhancement can thus be attributed to the carrier transfer between BFO and α(γ)-Fe2O3 across nano p/n junctions leading to enhanced carrier lifetime. Importantly, the magnetization of the nanocomposite (about 16 emu gm−1 at x = 0.20) provides a convenient way to collect the photocatalyst with the help of an external magnet for reuse.

Complex (multivalent/mixed valent) oxides involving two or more cations (e.g. ABO3, AB2O4 and A2B2O7) exhibit the most fascinating range of physical and chemical properties amongst the family of materials systems. There is growing interest in nanoscale forms of such oxides which emanates from the novel changes in their properties with size. To obtain nanomaterials with a high degree of crystallinity it is desirable to first make crystalline oxide powders by high temperature processing and then mill them down to nanometer size. In this paper we show that simple citric acid treatment of BiFeO3 and Bi2O3 powders leads to the desired micron-scale to nanoscale transformation, yielding nearly monodispersed nanoparticles. Importantly, these are highly dispersible and stable in water. By performing similar experiments on Fe3O4 and Fe2O3 we have elucidated the possible mechanism, which hinges on valence-controlled dissolution and ripening phenomena.

We report the synthesis of pure phase (cubic as well as orthorhombic phase) nanoparticles of Cd2SnO4 (10–15 nm) by a one step solution combustion method and demonstrate their applicability for energy harvesting in photoelectrochemical devices. The criticality of the process parameters in obtaining pure phase nanocrystals is emphasized through the study of the structural, optical and electronic properties. Doctor bladed Cd2SnO4 films, when used as photoanodes for solar water splitting, show a maximum photocurrent of 80 μA cm−2 at 0.5 V for the orthorhombic phase and 250 μA cm−2 at 0.6 V for the cubic phase with respect to an Ag/AgCl reference electrode indicating the good promise of Cd2SnO4 for energy harvesting.