Improved Conversion Efficiency Research Articles

High Efficiency Alkaline Iodine Batteries with Multi‐Electron Transfer Enabled by Bi/Bi2O3 Redox Mediator

AbstractThe multi‐electron transfer I−/IO3− redox couple is attractive for high energy aqueous batteries. Shifting from an acidic to an alkaline electrolyte significantly enhances the IO3− formation kinetics due to the spontaneous disproportionation reaction, while the alkaline environment also offers more favorable Zn anode compatibility. However, sluggish kinetics during the reduction of IO3− persists in both acidic and alkaline electrolytes, compromising the energy efficiency of this glorious redox couple. Here, we establish the fundamental redox mechanism of the I−/IO3− couple in alkaline electrolytes for the first time and propose that Bi/Bi2O3 acts as a redox mediator (RM) to “catalyze” the reduction of IO3−. This mediation significantly reduces the voltage gap between charge/discharge from 1.6 V to 1 V with improved conversion efficiency and rate capability. By pairing the Zn anode and the Bi/Bi2O3 RM cathode, the full battery with I−/IO3− redox mechanism achieves high areal capacity of 12 mAh cm−2 and stable operation at 5 mAh cm−2 for over 400 cycles.

Visualizing the Structure and Dynamics of Transition Metal-Based Electrocatalysts Using Synchrotron X-Ray Absorption Spectroscopy.

As the global energy structure evolves and clean energy technologies advance, electrocatalysis has become a focal point as a critical conversion pathway in the new energy sector. Transitional metal electrocatalysts (TMEs) with their distinctive electronic structures and redox properties show great potential in electrocatalytic reactions. However, complex reaction mechanisms and kinetic limitations hinder the improvement of energy conversion efficiency, highlighting the necessity for comprehensive studies on structure and performance of electrocatalysts. X-ray Absorption Fine Structure (XAFS) spectra stand out as a robust tool for examining the electrocatalyst's structures and performance due to its atomic selectivity and sensitivity to local environments. This review delves into the application of XAFS technology in characterizing TMEs, providing in-depth analyses of X-ray Absorption Near-Edge Structure (XANES) spectra, and Extended XAFS (EXAFS) spectra in both R-space and k-space. These analyses reveal intrinsic structural information, electronic interactions, catalyst stability, and aggregation morphology. Furthermore, the paper examines advancements in in-situ XAFS techniques for real-time monitoring of active site changes, capturing critical intermediate and transitional states, and elucidating the evolution of active species during electrocatalytic reactions. These insights deepen our understanding on structure-activity relationship of electrocatalysts and offer valuable guidance for designing and developing highly active and stable electrocatalysts.

In-situ cation-exchange deposited Ag2S/In4SnS8 of Z-type heterojunction coupled with DNA recycling amplification for photoelectrochemical biosensing

Herein, a novel photoelectrochemical (PEC) biosensor was developed utilizing an in situ cation-exchange method to deposit a high-performance Ag2S/In4SnS8, a Z-type heterojunction with co-shared S atoms, as a signal indicator and using DNA recycling amplification for the sensitive and accurate detection of miRNA-141. The photosensitive Ag2S deposited on the In4SnS8 surface not only facilitated the rapid generation of photoelectrons but also formed a Z-type heterojunction with In4SnS8, effectively inhibiting electron-hole pair recombination. This resulted in a considerable improvement in the photoelectric conversion efficiency of Ag2S/In4SnS8, yielding an ∼ 120-fold increase in photocurrent compared to that of In4SnS8 under 660-nm visible-light irradiation. Furthermore, the arborescent DNA structure formed by hybrid chain reaction (HCR) enhanced the steric effect, thereby reducing the PEC response. Importantly, numerous quenchers MnPP competed for light absorption and captured photogenerated electrons in the valence bands of In4SnS8 and Ag2S, reducing electron transfer to the electrode and further considerably reducing the photocurrent. This enabled the sensitive detection of miRNA-141 across a concentration range from 10 amol·L−1 to 100 pmol·L−1, with a limit of detection as low as 3.3 amol·L−1 (S/N = 3). The proposed biosensor exhibits excellent stability and is expected to be applied for detecting clinically relevant disease markers.

High-performance CIGS solar cells using a double active layers approach – SCAPS 1D optoelectronic modeling approach

One of the properties of the CIGS solar cell is that it can have an adjustable band gap energy. The band gap varies in the range from 1.01 to 1.7 eV as a function of materials content. Enhancing the bandgap profile of the active layer, which is where the majority of charge carrier photo-generation occurs, should significantly improve cell performance. Superimposing absorber layers with different electrical characteristics is one way of refining the bandgap profile and achieving these results. It is possible to analyze the optoelectronic output properties and simulate this active multilayer approach using a reference cell thanks to the SCAPS numerical modeling tool. Considering this, we have successfully simulated the following structure: CIGS2/CIGS1/SDL/ZnS/ZnO. The SDL which stands for Surface Defect Layer, has been considered for the property discontinuity interface, mainly characterized by the formation of defect states. That enabled to achieve realistic-like device with an improvement of power conversion efficiency (PCE) up to 11.98 %, i.e. 29.22 % and a fill factor (FF) of 82 % employing a total thickness of active layer of 800 nm. All simulations were performed considering experimental environment parameters, an external temperature of 300 K, light illumination of AM1.5G and defects states were assumed in both the bulk and at interfaces.

Enhancing photovoltaic cell design with multilayer sequential neural networks: A study on neodymium-doped ZnO nanoparticles

Multilayer sequential neural networks, a powerful machine learning model, demonstrate the ability to learn intricate relationships between input features and desired outputs. This study focuses on employing such models to design photovoltaic cells. Specifically, neodymium (Nd)-doped ZnO nanoparticles (NPs) were utilized as a photoanode for fabricating dye-sensitized solar cells (DSSCs). A natural dye extracted from Spinacia oleracea was employed, while two types of electrolytes, liquid and gel (polyethylene glycol-based), were used for comparative analysis. Extensive material characterization of the photoanode highlights the impact of Nd content on the physicochemical properties of ZnO. Notably, when the doped photoanode and gel electrolyte were combined, a substantial 110% improvement in power conversion efficiency (PCE) was achieved. Building on these findings, the machine learning model in this research accurately predicts the current-voltage (I-V) curve values for such photoanodes, with an impressive accuracy of 98%. Additionally, the model illuminates the significance of variables like crystal distortion, texture coefficient, and doping concentration, underscoring their importance in the context of photovoltaic cell design.

Advancing Solar Power Efficiency: Innovations in Material Science and System Optimization for Enhanced Solar Energy Conversion

This study aims to advance solar power efficiency through innovations in material science, surface engineering, and system optimization. The research integrates experimental testing and computational modeling to assess improvements in energy conversion efficiency. The methodology includes testing photovoltaic materials such as perovskite and multi-junction cells, anti-reflective coatings, self-cleaning surfaces, and optimizing panel orientation, cooling systems, and Maximum Power Point Tracking (MPPT) algorithms. Perovskite cells demonstrated a 22% increase in efficiency, while multi-junction cells achieved up to 35% efficiency. Anti-reflective coatings and self-cleaning surfaces improved energy capture by 4% and 7%, respectively. System optimization, including dual-axis trackers and AI-enhanced MPPT algorithms, provided additional efficiency gains of up to 25% and 10%, respectively. These findings demonstrate significant advancements in solar panel performance, providing a clear path for enhancing scalability and commercial viability in diverse environmental conditions. The integration of innovative materials and system optimizations presents a promising solution for making solar energy more sustainable and cost-effective. Future research should focus on improving the durability and reducing the costs of these technologies for widespread adoption.

Theoretical improvement of the energy conversion efficiency of an AZO/CdTe heterojunction solar cell to over 27% by incorporating FeSi2 as a second absorber layer

Abstract This paper presents the numerical analysis of cadmium telluride (CdTe) based solar cells using iron di silicide (FeSi2) as the second absorber layer and aluminum-doped zinc oxide (AZO) as the window layer. The photovoltaic performance of solar cells with Al/AZO/CdTe/FeSi2/Ni structure was analyzed and improved by SCAPS-1D software. When analyzing the influence of thickness and carrier concentration on the photovoltaic performance, it was found that the optimum values for the CdTe layer were 300 nm and 1015 cm-3, for the AZO layer they were 10 nm and 1018 cm-3, while for the FeSi2 layer they were 1 µm and 1018 cm-3. The defect density (Nt) at the AZO/CdTe and CdTe/FeSi2 interfaces was also analyzed, obtaining that the optimum value of Nt is 1010 cm-2 at both interfaces. Device optimization is achieved by obtaining a maximum Power Conversion Efficiency (PCE) of 27.22% with an open circuit voltage (Voc) of 0.63 V, a short circuit current density (Jsc) of 51.43 mA/cm2 and a fill factor (FF) of 83.06%, which makes FeSi2 a potential alternative for the development of CdTe-based solar cells due to its absorption of photons with lower energy wavelengths.

Fabrication of heterostructure multilayer devices through the optimization of Bi-metal sulfides for high-performance quantum dot-sensitized solar cells.

In this work, a titanium dioxide and lead sulfide (TiO2/PbS) nano-size heterostructure with tin sulfide was fabricated and coated via a two-step direct deposition process. Its microstructure, morphology, elemental composition, optical absorption, and photochemical activity were investigated. Linear sweep voltammetry and cyclic voltammetry curves substantiated its catalytic activity, indicating quantum dot effects of a well-developed space charge domain on the surface of the hybrid structure. These give rise to electron-hole recombination suppression and a high charge mobility rate. Moreover, direct stabilization was identified in current density, corresponding to the hybrid structures limiting the diffusion current process. Higher J SC values observed were substantiated by the role of quantum dot-size effects and enhanced crystalline structures, leading to a reduction in series resistance and an improved conversion efficiency of 10.05%. Overall, theoretical analyses and empirical findings indicated that the seamless migration of photoexcited electrons across the interfaces of SnS and PbS is linked to quantum dot effect synergy. This is facilitated by the space charge region, which serves as a conduit for efficient electron transfer between the respective materials.

Design and Simulation for Minimizing Non-Radiative Recombination Losses in CsGeI2Br Perovskite Solar Cells.

CsGeI2Br-based perovskites, with their favorable band gap and high absorption coefficient, are promising candidates for the development of efficient lead-free perovskite solar cells (PSCs). However, bulk and interfacial carrier non-radiative recombination losses hinder the further improvement of power conversion efficiency and stability in PSCs. To overcome this challenge, the photovoltaic potential of the device is unlocked by optimizing the optical and electronic parameters through rigorous numerical simulation, which include tuning perovskite thickness, bulk defect density, and series and shunt resistance. Additionally, to make the simulation data as realistic as possible, recombination processes, such as Auger recombination, must be considered. In this simulation, when the Auger capture coefficient is increased to 10-29 cm6 s-1, the efficiency drops from 31.62% (without taking Auger recombination into account) to 29.10%. Since Auger recombination is unavoidable in experiments, carrier losses due to Auger recombination should be included in the analysis of the efficiency limit to avoid significantly overestimating the simulated device performance. Therefore, this paper provides valuable insights for designing realistic and efficient lead-free PSCs.

Sputter-deposited TiOx thin film as a buried interface modification layer for efficient and stable perovskite solar cells

Despite perovskite solar cells (PSCs) based on a SnO2 hole-blocking layer (HBL) are achieving excellent performance, the non-perfect buried interface between the SnO2 HBL and the perovskite layer is still an obstacle in achieving further improvement in power conversion efficiency (PCE) and stability. The poor morphology with numerous defects and the energy level mismatch at the buried interface constrain the open circuit voltage and cause instability. Herein, a sputter-deposited TiOx thin film is used as a buried interface modification layer to address the aforementioned issues. Utilizing in situ grazing-incidence small-angle X-ray scattering (GISAXS) during the sputter deposition, we monitor and unveil the growth process of the TiOx thin film, identifying a 10 nm thickness optimum. The defects at the buried interface are passivated through tuning the growth, leading to a suppressed non-radiative recombination and improved PCE (from 22.19 % to 23.93 %). The evolution of the device performance and the degradation process of PSCs using operando grazing-incidence wide-angle X-ray scattering (GIWAXS) under the protocol ISOS-L-1I explains the enhanced stability introduced by the buried interface modification via a sputter-deposited TiOx thin layer. The perovskite decomposition process and the detrimental formation of PbI2 are both slowed down by the TiOx thin layer.

High Efficiency Alkaline Iodine Batteries with Multi-Electron Transfer Enabled by Bi/Bi2O3 Redox Mediator.

The multi-electron transfer I-/IO3 - redox couple is attractive for high energy aqueous batteries. Shifting from an acidic to an alkaline electrolyte significantly enhances the IO3 - formation kinetics due to the spontaneous disproportionation reaction, while the alkaline environment also offers more favorable Zn anode compatibility. However, sluggish kinetics during the reduction of IO3 - persists in both acidic and alkaline electrolytes, compromising the energy efficiency of this glorious redox couple. Here, we establish the fundamental redox mechanism of the I-/IO3 - couple in alkaline electrolytes for the first time and propose that Bi/Bi2O3 acts as a redox mediator (RM) to "catalyze" the reduction of IO3 -. This mediation significantly reduces the voltage gap between charge/discharge from 1.6 V to 1 V with improved conversion efficiency and rate capability. By pairing the Zn anode and the Bi/Bi2O3 RM cathode, the full battery with I-/IO3 - redox mechanism achieves high areal capacity of 12 mAh cm-2 and stable operation at 5 mAh cm-2 for over 400 cycles.

Organic Salt Buffer Layer Enables High‐Performance NiOx‐Based Inverted Perovskite Solar Cells

The merits of a low‐cost fabrication process, suitable band structure, excellent wettability to perovskite precursor, and outstanding stability ensure NiOx as a hole transport material with beneficial characteristics to construct high‐performance perovskite solar cells (PSCs). However, direct contact between perovskite and NiOx causes delamination and chemical instability and thus results in poor carrier transport and short device lifespan. Here, we propose a solution for this issue by introducing an organic salt additive 4‐(trifluoromethyl) benzylammonium formate (TFMBAFa) in the perovskite precursor to passivate perovskite film and NiOx@(2‐(3,6‐dimethyl‐9H‐carbazol‐9‐yl) ethyl) phosphonic acid (Me‐2PACz) composited hole transport layer (HTL), and thus construct a buffer layer between perovskite‐HTL interface. The effective diminishing of NiOx/perovskite interfacial reactions and defects results in enhanced carrier transport. Consequently, the target device achieves simultaneous improvements in power conversion efficiency (24.2%), storage stability (T100 > 1400 h), thermal stability (T80 > 1000 h), and operational stability (T70 > 850 h), where T100, T80, and T70 refer to the retention of 100%, 80%, and 70% of initial PCE, respectively. This work provides an effective strategy to advance the performance of NiOx‐based inverted PSCs.

Surface functionalized porous MXene (Ti3C2Tx)/Polyethyleneimine membrane for efficient osmotic energy conversion

The development of ion-selective membranes is crucial for achieving efficient osmotic power conversion in reverse electrodialysis system. However, balancing ion selectivity and ion permeability in membranes remains a challenge, limiting improvements in energy conversion efficiency for practical applications. In this study, we develop efficient cation exchange membranes by integrating versatile aromatic hydroxyl groups with MXene nanosheets and polyethyleneimine (PEI) into their lamellar structure. This approach holds promise for achieving non-swelling, high selectivity, and enhanced power density for osmotic energy conversion. The abundance positive surface charge within PEI molecules, combined with the 2D sub-nanochannels of MXene nanosheets, facilitates the biomimetic replication of channel size, chemical groups, and adjustable charge density in the resulting membranes. The fabrication of these membranes is easily achieved through simple hydrothermal, functionalization, and surface-charged techniques, suggesting promising scalability. These membranes exhibit remarkable stability against swelling in aqueous solutions for up to 25 days and demonstrate a high selectivity of 0.95 and a superior output power density of 18.3 W/m2 in artificial river water and seawater.

Effluent nozzles in reverse-vortex-stabilized microwave CO2 plasmas for improved energy efficiency

Energy efficiency and conversion in a reverse-vortex microwave CO2 plasma are enhanced by optimizing the thermal trajectories using a converging diverging nozzle in subsonic flows. The nozzle mixes cold, unconverted gas at the edge of the flow with hot, active gas in the middle of the flow. Temperature measurements are taken of the quartz tube as well as just above the nozzle inlet and directly after the nozzle and presented to elucidate differences in performance. Measurements show significant improvements in conversion and energy efficiency, especially at pressures close to atmospheric pressure (500 – 900 mbar). In addition an improvement in plasma stability when adding a converging diverging nozzle. Thermal measurements also point towards a shift in energy loss mechanisms when changing flow configurations.

Recent Progress of Three-Dimensional Graphene-Based Composites for Photocatalysis.

Converting solar energy into fuels/chemicals through photochemical approaches holds significant promise for addressing global energy demands. Currently, semiconductor photocatalysis combined with redox techniques has been intensively researched in pollutant degradation and secondary energy generation owing to its dual advantages of oxidizability and reducibility; however, challenges remain, particularly with improving conversion efficiency. Since graphene's initial introduction in 2004, three-dimensional (3D) graphene-based photocatalysts have garnered considerable attention due to their exceptional properties, such as their large specific surface area, abundant pore structure, diverse surface chemistry, adjustable band gap, and high electrical conductivity. Herein, this review provides an in-depth analysis of the commonly used photocatalysts based on 3D graphene, outlining their construction strategies and recent applications in photocatalytic degradation of organic pollutants, H2 evolution, and CO2 reduction. Additionally, the paper explores the multifaceted roles that 3D graphene plays in enhancing photocatalytic performance. By offering a comprehensive overview, we hope to highlight the potential of 3D graphene as an environmentally beneficial material and to inspire the development of more efficient, versatile graphene-based aerogel photocatalysts for future applications.

Quasi-linear superelasticity and associated elastocaloric effect in boron-doped polycrystalline Ni-Mn-Ti alloys

Ni-Mn-Ti shape memory alloys show great potential in solid-state elastocaloric cooling owing to very prominent elastocaloric effect along with first-order stress-induced martensitic transformation. However, large stress hysteresis inherent to martensitic transformation greatly restricts the energy efficiency and cyclic stability of elastocaloric response. Here, we demonstrate the effective manipulation of stress hysteresis as well as the resulting elastocaloric effect through doping boron to Ni-Mn-Ti alloys. With the incremental boron content in (Ni50Mn31Ti19)100–xBx (x = 0, 0.2, 0.5, 1, 1.5) alloys, a plateau-type superelastic behavior with large stress hysteresis gradually evolves into a quasi-linear one with slim hysteresis, giving rise to significant improvement in the energy conversion efficiency of elastocaloric response. In a (Ni50Mn31Ti19)99B1 alloy, the coefficient of performance of material (COPmat) can be as high as 24 ∼ 33. Moreover, under a compressive strain of 4%, large cooling |ΔTad| values higher than 6.5 K in the (Ni50Mn31Ti19)99B1 alloy are maintained for over 8000 superelastic cycles, showing an enhancement of one order of magnitude in the cyclability with respect to that of boron-free Ni50Mn31Ti19 alloy. We attribute the enhanced elasocaloric response to the significantly improved mechanical properties but reduced stress hysteresis endowed by relatively high content of boron doping.

Highly reliable anti-reflection radiative cooling glass applicable to thermal management of solar cells

The encapsulation materials of solar cells have a significant impact on the performance and stability of the cells. Herein, an anti-reflection radiative cooling (ARRC) glass for photovoltaic (PV) devices is proposed by multi-layer design. Harnessing the synergy of anti-reflection layers and a transparent radiative cooling layer, ARRC glass can dissipate heat radiatively through molecular vibrations. Concurrently, it maintains the functionality and aesthetics of the associated devices. ARRC possesses four prominent characteristics, enabling it to serve as an encapsulation glass to enhance the performance and stability of solar cells. 1. Superior maximum visible light transmittance (0.954, 602 nm). 2. Outstanding mid-infrared emittance (0.951). 3. Excellent UV blocking performance (reached 99 % at 320 nm). 4. Marvelous thermal management performance (6.6 °C cooling for multi-crystalline silicon solar cells and 8.6 °C cooling for perovskite cells). Excellent anti-reflection and cooling performance of ARRC glass improves conversion efficiency by 1.08 % and 1.79 % for multi-crystalline silicon solar cells and perovskite solar cells (PSCs), respectively. Moreover, ARRC glass enhances the UV stability of PSCs by 4 times and significantly alleviates the thermal decomposition of PSCs. The ARRC glass, with excellent adhesion, scalability, economy, and stability, is expected to be applied on a large scale and further contribute to energy and environment sustainability.

Bioupcycling Methane and CO2 for Succinate Production by an Engineered Type I Methanotrophic Bacterium.

Methane, a byproduct of agricultural activities, has shown potential as a nonedible substrate for biomanufacturing. The production of succinate by a methanotrophic bacterium utilizing methane presents an innovative route for the sustainable synthesis of chemicals. In this study, Methylotuvimicrobium buryatense 5GB1S was genetically modified through the reconstruction of an artificial serine cycle to enable the bioconversion of both methane and CO2 into succinate. The 13C labeling analysis confirmed the CO2 fixing in M. buryatense 5GB1S, leading to a 46% improvement in carbon conversion efficiency and a 107% increase in succinate production compared to the wild-type strain. The transcriptome data on carbon metabolisms was assessed to guide future optimizations for strengthening the overall carbon flux from methane to succinate. Finally, the maximum succinate titer of 299.36 mg/L was achieved under oxygen-limited conditions in 3 L bioreactors, which resulted in the volumetric productivity of 199.60 mg/L/day, representing a 23-fold enhancement compared to the wild-type strain. This study offers a new strategy for upcycling greenhouse gases into succinate in a sustainable manner through methanotrophic-based biomanufacturing.

Minimizing voltage loss for perovskite solar cells via synergistically passivating defects and reinforcing interfacial electric field

Perovskite solar cells have attracted much attention because of their excellent photoelectric properties. However, non-radiative recombination losses due to interface defects limit the open circuit voltage (Voc) of PSCs, which prevents further improvement in power conversion efficiency (PCE). To solve this problem, we introduced Li2SO4 into the SnO2/perovskite interface to obtain a higher Voc through interfacial passivation and enhancement of the interface electric field. Herein, Li+ presents bottom-up diffusion into perovskite surface, and forms dipoles with FA to enhance the interface electric field. Furthermore, SO in SO42- passivates Sn4+ on the surface of SnO2 and Pb2+ at the buried interface of perovskite. This method combines interfacial passivation with synchronous electric field enhancement, which promotes interfacial carrier migration and reduces non-radiative recombination and voltage loss (Vloss) at the interface. As a result, the SLS-device exhibits an enhanced Voc of 1.25 V, with a very low Vloss of 0.33 V, achieving an outstanding PCE of 24.31 %. Moreover, the device maintained 90 % of the initial PCE after exposure to ambient air for 1000 h. This work demonstrates the necessity to co-design the interface microstructure and electric field distribution for reducing the energy loss of perovskite photovoltaic devices and promoting the efficiency of interfacial charge transport.

Studies on InZnMgO amorphous buffer layer for Cu(In,Ga)(S,Se)2 solar cell

This study explores the effectiveness of an amorphous buffer layer, specifically Indium Zinc Magnesium Oxide (IZMO), as an alternative buffer in Copper Indium Gallium Sulfide Selenide (CIGSSe) solar cells. The findings reveal a significant impact on efficiency through precise adjustment of the Mg/(In+Zn+Mg) ratio (MIZM) from 0 to 0.23. The bandgap exhibits a consistent increase with an ascending Mg/(In+Zn+Mg) ratio, transitioning from 3.42 eV to 3.63 eV for IZMO prepared with Ar and from 3.18 eV to 3.53 eV for IZMO prepared with an Ar+O2 gas mixture, respectively. This rise is attributed to the augmentation of the conduction band minimum (EC) of IZMO resulting from the addition of MgO. Moreover, an increase in the Mg/(In+Zn+Mg) ratio correlates with improved conversion efficiency, escalating from 6.31 % to 9.19 %. Notably, the open-circuit voltage experiences a rise from 0.430 V to 0.520 V. This is attributed to the heightened EC of IZMO due to MgO addition, which mitigates recombination between the light-absorbing layer and the buffer layer, consequently elevating the open circuit voltage. The addition of MgO also enhances the resistance of the buffer layer, contributing to an increase in shunt resistance and a subsequent decrease in leakage current. Conversely, IZMO introduced with O2 exhibits inferior performance akin to IZO, attributable to substantial sputter damage induced by O2 introduction.