Immobilized Gold Nanoparticles on a Glass-Based Scaffold for Direct Solar-Driven H2 from Water Vapor
Riya Haldar., Gadudhula Ganesh., Kaustuv Chatterjee., Indrajeet Mandal., Anustup Chakraborty., Keya Haldar., Prabir Pal., Goutam Kishore Gupta., N M Anoop Krishnan., Manohar Chirumamilla., Eswaraiah Varrla., Ama
Journal, ACS Materials Letters, 2025, Quartile: Q1, DOI Link
View abstract ⏷
Solar-driven green hydrogen (H2) production through photocatalytic water splitting is a promising solution to combat climate change. A key challenge lies in developing photocatalyst materials capable of efficiently splitting water vapor under practical conditions. In this study, we present a photocatalytic system based on gold nanoparticles immobilized on a glass-based porous scaffold through reactive metal support interactions. This structure exhibits a high solar-to-hydrogen (STH) conversion efficiency of 2.2% under simulated solar light. Long-term cycling tests demonstrate stable H2 evolution, with observed declines in efficiency caused by surface hydroxyl and carboxyl group formation, although it is effectively restored through plasma treatment. These findings provide valuable insights into the design of robust and efficient photocatalytic materials, advancing the potential path for scalable commercial applications.
Thermographic inspections of solar photovoltaic plants in India using Unmanned Aerial Vehicles: Analysing the gap between theory and practice
Journal, Renewable Energy, 2024, Quartile: Q1, DOI Link
View abstract ⏷
Aerial inspection of solar PV plants using Unmanned Aerial Vehicles (UAVs) is gaining traction due to benefits such as no downtime and cost-effectiveness. This technology is proven to be the low-cost alternative to conventional approaches involving visual inspection and I-V curve tracing to identify physical damages and underperforming strings, respectively. Though the use of UAVs for thermographic solar PV inspection is a popular alternative in developed countries, its use in developing economies experience various challenges. Studies emphasizing these challenges especially in the context of rapid evolution of drones are limited. To overcome this limitation, literature scoping, a one-on-one survey, focus group discussion, and a flight campaign using a UAV with a thermal payload is conducted in India to identify the limitations. These are further categorized into Technical, Behavioural, Implementation, Pre-deployment, Deployment, and Post-deployment categories. The relevance and significance of each challenge are analysed using a hybrid multi-criteria framework developed in this study. Findings of this study highlight the importance of drone regulations, technology readiness, and workshops for drone pilots, industry professionals, and solar developers in India. This study aid developing economies in devising strategies that can promote the use of UAVs for solar PV plant commissioning activities.
Experimental study of zero degree focus
Nikola Starcevic., Mark Breese., Srdjan Petrovic
Conference, AIP Conference Proceedings, 2024, Quartile: Q4, DOI Link
View abstract ⏷
Ion beam focusing is a pivotal factor for enhancing ion microscopy methodologies. We have concluded the investigation into particle focusing to confirm the zero-degree focusing effect. This involved examining the angular distributions of H+ ions channeled through a thin silicon crystal, utilizing a methodology specifically tailored for this purpose. This phenomenon, fundamental for advancing microscopy techniques, has been experimentally measured and theoretically elucidated. In the process of ion channeling, the particles establish oscillatory motion along the axis of the channel with a period equal to the reduced crystal thickness. The energy of the H+ ions is varied in the MeV range, while the thickness of the silicon crystal remained constant at 100nm. These experimental conditions involve a reduced crystal thickness which encompasses the first and second rainbow cycles. The aim is to measure the zero-degree focusing effect occurring at the end of the rainbow cycle.
Synergistic metal halide perovskite@metal-organic framework hybrids for photocatalytic CO2 reduction
Saandra Sharma., G Krishnamurthy Grandhi., Mahendra B Choudhary., Swathi Ippili., Venkatesha R Hathwar., Paola Vivo., Rabindranath Lo., Kolleboyina Jayaramulu
Journal, iScience, 2024, Quartile: Q1, DOI Link
View abstract ⏷
The photocatalytic reduction of carbon dioxide (CO2) into multi-electron carbon products remains challenging due to the inherent stability of CO2 and slow multi-electron transfer kinetics. Here in, we synthesized a hybrid material, cesium copper halide (Cs3Cu2I5) intercalated onto two-dimensional (2D) cobalt-based zeolite framework (ZIF-9-III) nanosheets (denoted as Cs3Cu2I5@ZIF-1) through a simple mechanochemical grinding. The synergy in the hybrid effectively reduces CO2 to carbon monoxide (CO) at 110 ?mol/g/h and methane at 5 ?mol/g/h with high selectivity, suppressing hydrogen evolution. Further, we have investigated additional Cs3Cu2I5@ZIF hybrids with varying ZIF-9-III amounts, confirming their selective CO2 reduction to methane over hydrogen. Density functional theory (DFT) calculations reveal a non-covalent interaction between Cs3Cu2I5 and ZIF-9-III, with electron transfer suggesting potential for improved photocatalysis
A comprehensive review on realization of self-cleaning surfaces by additive manufacturing
Sherin T., Dalapati G K., Ramakrishna S., Sangaraju S., Krishnamurthy S.,
Journal, Progress in Additive Manufacturing, 2024, Quartile: Q1, DOI Link
View abstract ⏷
Self-cleaning surfaces revolutionizing the technology world due to their novel property of cleaning themselves, and its multi-functional self-cleaning surfaces exhibit at least one or more functional properties (transparent, conducting, anti-bacterial, anti-corrosion, etc.) This review article focuses on the fundamentals of wettability, material parameters controlling surface wettability and three different paths to realization of self-cleaning surfaces, i.e., (i) super-hydrophobic, (ii) super-hydrophilic and (iii) photocatalytic. The subsequent part of the article mostly focuses on the super-hydrophobic path towards realizing self-cleaning surfaces. In the super-hydrophobic path, the objective is to make the surface extremely repellent to water so that water droplets slide and roll off from the surface. The next section of the review article focuses on the role of additive manufacturing in the fabrication of super-hydrophobic micro-structures. Amidst the different fabrication processes of self-cleaning surfaces, additive manufacturing stays ahead as it has the manufacturing capacity to create complex micro-structures in a scalable and cost-effective manner. A few prominent types of additive manufacturing processes were strategically chosen which are based on powder bed fusion, vat photopolymerization, material extrusion and material jetting techniques. All these additive manufacturing techniques have been extensively reviewed, and the relative advantages and challenges faced by each during the scalable and affordable fabrication of super-hydrophobic self-cleaning surfaces have been discussed. The article concludes with the latest developments in this field of research and future potential. These surfaces are key to answer sustainable development goals in manufacturing industries. Graphical abstract: (Figure presented.) © The Author(s) 2024.
H-Glass Supported Hybrid Gold Nano-Islands for Visible-Light-Driven Hydrogen Evolution
Indrajeet Mandal., Jagannath Gangareddy., Abimannan Sethurajaperumal., Manohar Chirumamilla., Murugasenapathi Nk., Susmita Bera., Pratyasha Rudra., Vanmathi Ravichandran., Sandip Bysakh., K D M Rao., Rajiv K Singh., N M Anoo
Journal, Small, 2024, Quartile: Q1, DOI Link
View abstract ⏷
Flat panel reactors, coated with photocatalytic materials, offer a sustainable approach for the commercial production of hydrogen (H) with zero carbon footprint. Despite this, achieving high solar-to-hydrogen (STH) conversion efficiency with these reactors is still a significant challenge due to the low utilization efficiency of solar light and rapid charge recombination. Herein, hybrid gold nano-islands (HGNIs) are developed on transparent glass support to improve the STH efficiency. Plasmonic HGNIs are grown on an in-house developed active glass sheet composed of sodium aluminum phosphosilicate oxide glass (H-glass) using the thermal dewetting method at 550 °C under an ambient atmosphere. HGNIs with various oxidation states (Au, Au, and Au) and multiple interfaces are obtained due to the diffusion of the elements from the glass structure, which also facilitates the lifetime of the hot electron to be ?2.94 ps. H-glass-supported HGNIs demonstrate significant STH conversion efficiency of 0.6%, without any sacrificial agents, via water dissociation. This study unveils the specific role of H-glass-supported HGNIs in facilitating light-driven chemical conversions, offering new avenues for the development of high-performance photocatalysts in various chemical conversion reactions for large-scale commercial applications.
Potential Benefits, Challenges and Perspectives of Various Methods and Materials Used for Hydrogen Storage
Nagaprasad Puvvada., Pravas Kumar Panigrahi., Basavaiah Chandu.,
Journal, Energy and Fuels, 2024, Quartile: Q1, DOI Link
View abstract ⏷
Fossil fuels, which are extremely harmful to the environment and not renewable, predominantly serve the majority of the worlds energy needs. Currently, hydrogen is regarded as the fuel of the future due to its many advantages, such as its high calorific values, high gravimetric energy density, eco-friendliness, and nonpolluting nature, as well as being a zero-emission energy source. For sustainable global growth, it is essential to produce and store hydrogen on a large scale by utilizing renewable energy sources. However, hydrogen storage systems, particularly for vehicle on-board applications, face challenges in terms of developing energy-efficient and affordable techniques and materials due to hydrogens buoyancy, lightness, and high diffusivity. This Review systematically discusses various hydrogen storage methods and materials, including physical storage like compressed gas, physical adsorption storage like carbon-based materials, metal-organic frameworks (MOFs), and other porous materials, as well as chemical storage like ammonia, methanol, formic acid, liquid organic hydrogen carriers (LOHCs), metal hydrides, and two-dimensional MXene-based materials. The advantages of various storage mechanisms are thoroughly discussed, as well as any potential implementation difficulties for real-world uses and future prospects.
Efficient photocatalytic green hydrogen production using crystalline elemental Boron nanostructures under visible light
Paramita Maiti., Manikanta Majji., Ravva Mahesh Kumar.,
Journal, International Journal of Hydrogen Energy, 2024, Quartile: Q1, DOI Link
View abstract ⏷
Green Hydrogen emerges as a promising energy solution in the quest for achieving Net Zero goals. The application of particulate semiconductors in photocatalytic water splitting introduces a potentially scalable and economically viable technology for converting solar energy into hydrogen. Overcoming the challenge of efficiently transferring photoelectrons and photoholes for both reduction and oxidation on the same catalyst is a significant hurdle in photocatalysis. In this context, we introduce highly efficient crystalline elemental boron nanostructures as photocatalysts, employing a straightforward and scalable synthesis method yield green hydrogen production without the need for additional co-catalysts or sacrificial agents. The resulting photocatalyst demonstrates stability and high activity in H 2 production, achieving over 1 % solar-to-hydrogen energy conversion efficiency (>15,000 ?mol. g ?1.h ?1 ) during continuous 12-h illumination. This efficiency is credited to broad optical absorption and the crystalline nature of boron nanostructures, paving the way for potential scale-up of reactors using crystalline boron photocatalysts.
Emerging trends in cooling technologies for photovoltaic systems
Ezrah Mariam., Avishek Kumar., Brindha Ramasubramanian., Vundrala Sumedha Reddy., Goutam Kumar Dalapati., Seeram Ramakrishna., Satheesh Krishnamurthy
Journal, Renewable and Sustainable Energy Reviews, 2024, Quartile: Q1, DOI Link
View abstract ⏷
Photovoltaic systems (PV), particularly solar photovoltaics, are gaining popularity as renewable energy sources. The rapid deployment of PV systems has attracted substantial investments, with around $170 billion projected by 2025. However, challenges like dust accumulation, solar radiation, and temperature rise hinder PV efficiency. Elevated temperatures, exceeding standard levels, notably decrease voltage output and overall electricity generation efficiency. This review provides a comprehensive overview of recent cooling techniques adopted to enhance solar PV performance. Beginning with an introduction to global warming's impact and renewable energy's significance, the article explores cooling methodologies for solar PVs. These encompass Absorption & adsorption-based, PV/T hybrid, Microtechnology-based, and Water and air-based cooling systems. The review concludes this section with a detailed table comparing cooling technologies' performance, benefits, and challenges. The review then delves into four primary cooling techniques: Active cooling, Passive cooling, Nanofluid-based cooling, and Thermoelectric cooling. Passive cooling, which effectively reduces PV system temperature without external energy sources, is highlighted. Modalities of Passive cooling methods, such as Radiative cooling, Evaporative cooling, Liquid immersions, and Material coatings, are elaborated. Concluding, the article addresses challenges, opportunities, and future prospects related to diverse cooling techniques' utilisation, aiming to elevate solar PV system efficiency.
Effects of Initial Phase on Silicon Nanoparticles Formation in Femtosecond Laser Ablation
Kanaka Ravi Kumar., B Chandu., M S S Bharati., S Venugopal Rao., S V S Nageswara Rao
Journal, Journal of Physics: Conference Series, 2022, Quartile: Q3, DOI Link
View abstract ⏷
We report on the ultrafast (femtosecond) laser ablation of monocrystalline Si (100), polycrystalline Si, and Si (100) capped with a SiO2 layer. The target material was ablated using femtosecond laser pulses (?50 fs duration, 1 kHz repetition rate, and 800 nm wavelength) with an input energy of ?100 ?J in acetone medium to fabricate Si Nanoparticles (NPs). The average size of NPs produced by Si (100) was found to be less than that of the particles produced by poly Si. Ablation of Si caped with SiO2 resulted in bigger Si NPs together with a low concentration of SiO2 NPs. NPs were found to be of polycrystalline in all three cases irrespective of the initial phase.
Radiation Response of HfOx-Based Resistive Random Access Memory (RRAM) Devices
Arun Nimmala., Anand P Pathak., M Ghanashyam Krishna., Venkata Sai Nageswara Rao Sunkaranam
Journal, ACS Applied Electronic Materials, 2022, Quartile: Q1, DOI Link
View abstract ⏷
A report on the fabrication and radiation response of HfOx thin film-based resistive random access memory (RRAM) devices is presented in this study. Au/HfOx/Au cross-bar (10 ?m × 10 ?m) structures were used to study the effects of ion irradiation on their switching properties. One hundred twenty megaelectron volt (120 MeV) Ag7+ ions with fluence values ranging from 5E10 to 5E12 ions/cm2 were employed in this work. The resistance (high to low) ratio was found to increase until a critical fluence of 5E11 ions/cm2 was reached, and it decreased beyond this fluence. Furthermore, it is observed that the singly charged positive oxygen-vacancy defects (VO+) are more dominant and have a major contribution in the switching cycles for these RRAM devices. The observed trends in the electrical properties of these devices are correlated with the changes in the densities of charged defects relative to neutral defects in the switching medium. Possibilities of employing these RRAM devices as radiation detectors are also discussed.
Enhanced Metal-Insulator Transition in Freestanding VO 2 Down to 5 nm Thickness
Xinghua Li., Yu Cao., Hanyu Wang., Hongna Xing., Xiao Li., Kun Han., Liang Wu., Chen Ye., Ke Huang., Dong Chen Qi., X Renshaw Wang
Journal, ACS Applied Materials and Interfaces, 2021, Quartile: Q1, DOI Link
View abstract ⏷
Ultrathin freestanding membranes with a pronounced metal-insulator transition (MIT) have huge potential for future flexible electronic applications as well as provide a unique aspect for the study of lattice-electron interplay. However, the reduction of the thickness to an ultrathin region (a few nm) is typically detrimental to the MIT in epitaxial films, and even catastrophic for their freestanding form. Here, we report an enhanced MIT in VO2-based freestanding membranes, with a lateral size up to millimeters and the VO2 thickness down to 5 nm. The VO2 membranes were detached by dissolving a Sr3Al2O6 sacrificial layer between the VO2 thin film and the c-Al2O3(0001) substrate, allowing the transfer onto arbitrary surfaces. Furthermore, the MIT in the VO2 membrane was greatly enhanced by inserting an intermediate Al2O3 buffer layer. In comparison with the best available ultrathin VO2 membranes, the enhancement of MIT is over 400% at a 5 nm VO2 thickness and more than 1 order of magnitude for VO2 above 10 nm. Our study widens the spectrum of functionality in ultrathin and large-scale membranes and enables the potential integration of MIT into flexible electronics and photonics.
Effects of Initial Grain Size and Laser Parameters on HfO2 Nanoparticles Prepared Using Femtosecond Laser Ablation in Liquids
A Mangababu., Ch Sianglam., B Chandu., D K Avasthi., S Venugopal Rao., S V S Nageswara Rao
Journal, Journal of Electronic Materials, 2021, Quartile: Q2, DOI Link
View abstract ⏷
The fabrication of an intriguing nano-fiber network interconnected to crystalline spherical shaped nanoparticles of HfO has been achieved by femtosecond (fs) pulsed laser ablation in liquids. Understanding the fundamental reasons behind the formation of such heterostructures is important to scale up such process for other varieties of electronic materials. The present work has been designed to verify the impact of initial grain size on the final heterostructures formed. The overall plasma density and its composition were varied since the laser interaction with the matter is affected by the initial grain/particle size. This work covers the effects of initial grain sizes on HfO hetero-nanomaterials formed by a controlled ball-milling process. The ablation was performed with fs laser pulses on HfO pellets with two different initial grain sizes in distilled water and ethanol. The formed nanoparticles (NPs) had a spherical shape along with an interesting nano-fiber-like structure. The NPs were found to be polycrystalline in nature, and the fiber-like structures were found to be amorphous in nature. Further, the formation of high-temperature and high-pressure phases of HfO NPs (tetragonal/cubic HfO) was observed along with a room-temperature phase (monoclinic HfO). A combination of ball milling and ultrafast laser ablation appears to be a preferred method for synthesizing smaller NPs of exotic non-equilibrium phases.
Tailoring magnetic order via atomically stacking 3d/5d electrons to achieve high-performance spintronic devices
Ke Huang., Liang Wu., Maoyu Wang., Nyayabanta Swain., Yongzheng Luo., Dong Chen Qi
Journal, Applied Physics Reviews, 2020, Quartile: Q1, DOI Link
View abstract ⏷
The ability to tune magnetic orders, such as magnetic anisotropy and topological spin texture, is desired to achieve high-performance spintronic devices. A recent strategy has been to employ interfacial engineering techniques, such as the introduction of spin-correlated interfacial coupling, to tailor magnetic orders and achieve novel magnetic properties. We chose a unique polar-nonpolar LaMnO/SrIrO superlattice because Mn (3d)/Ir (5d) oxides exhibit rich magnetic behaviors and strong spin-orbit coupling through the entanglement of their 3d and 5d electrons. Through magnetization and magnetotransport measurements, we found that the magnetic order is interface-dominated as the superlattice period is decreased. We were able to then effectively modify the magnetization, tilt of the ferromagnetic easy axis, and symmetry transition of the anisotropic magnetoresistance of the LaMnO/SrIrO superlattice by introducing additional Mn (3d) and Ir (5d) interfaces. Further investigations using in-depth first-principles calculations and numerical simulations revealed that these magnetic behaviors could be understood by the 3d/5d electron correlation and Rashba spin-orbit coupling. The results reported here demonstrate a new route to synchronously engineer magnetic properties through the atomic stacking of different electrons, which would contribute to future applications in high-capacity storage devices and advanced computing.
Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy
Liang Cheng., Tarapada Sarkar., James Lourembam., Roxanne Tutchton., Daming Zhao., Jian Xin Zhu., Thirumalai Venkatesan., Elbert E M Chia
Journal, Applied Physics Letters, 2020, Quartile: Q1, DOI Link
View abstract ⏷
Transparent conductive oxides (TCOs) - materials that have the twin desirable features of high optical transmission and electrical conductivity - play an increasingly significant role in the fields of photovoltaics and information technology. As an excellent TCO, Ta-doped anatase TiO2 shows great promise for a wide range of applications. Here, terahertz time-domain spectroscopy is used to study the complex optical conductivity ? ? of the TCO - heavily Ta-doped TiO2 thin films with different Ta-doping concentrations, in the frequency range of 0.3-2.7 THz and the temperature range of 10-300 K. Fitting the complex optical conductivity to a Drude-like behavior allows us to extract the temperature dependence of the effective mass, which suggests the existence of many-body large polarons. Moreover, the carrier scattering rate of Ta-doped TiO2 with different carrier concentrations agrees with the interacting polaron gas theory. Our results suggest that with increasing electron density in TiO2, the interaction between polarons is larger and electron-phonon coupling is smaller, which is beneficial for achieving high mobility and conductivity in TiO2.
