We embark on an exciting journey to identify the ideal electron transport layers (ETL) and hole transport layers (HTL) that can significantly boost the efficiency of CsPbI2Br-based solar cells. Utilizing first-principles calculations with the modified Becke-Johnson potential (mBJ) and spin-orbit correction, we uncovered the direct band gap property of CsPbI2Br, measuring an impressive 1.81 eV. Coupled with its remarkable absorption coefficient of 105 cm?1 and minimal reflectivity throughout the visible spectrum, this material stands out as an emerging absorber layer for photovoltaic cells. Also, using cutting-edge SCAPS-1D simulations, we explore a range of ETL materials, including TiO2, ZnO, CdS, STO, WS2, and Nb2O5, alongside HTL options like NiO, Spiro, SnS, CuI, Cu2O, and CuSbS2. Our findings reveal that Nb2O5 and Cu2O emerge as the most promising candidates for ETL and HTL to enhance the performance of CsPbI2Br absorbers, opening the door to more efficient solar energy solutions. The efficiencies achieved with the ETL and HTL-based solar cells, specifically Au/CsPbI2Br/Nb2O5/FTO and Au/Cu2O/CsPbI2Br/FTO, are impressive, standing at 17.91 % and 18.13 %, respectively. Moreover, various factors such as the thickness of the absorbing layer, HTL, and ETL, along with total defect density (Nt), donor and acceptor defect densities of both the absorber and the transport layers, and the device temperature, significantly influence the performance metrics of the Au/Cu2O/CsPbI2Br/Nb2O5/FTO solar cell. Our findings reveal impressive values: a maximum open-circuit voltage (Voc) of 1.21 V, a short-circuit current (Jsc) of 32.47 mA/cm2, a fill factor of 87.7 %, and an efficiency (?) of 22.31 %. These findings exceed the previously reported values for halide perovskite based solar cells, underscoring the promise of this research in shaping the future of cutting-edge perovskite-based solar cells.

The development of direct methanol fuel cells (DMFCs) relies on designing replacements for benchmark platinum (Pt)?based electrocatalysts toward methanol oxidation reaction (MOR) that exhibit high resistance to CO poisoning, improve kinetic sluggishness, devoid of unwanted intermediates, low catalyst cost, and wide operating conditions. This study presents the development of defect engineering N?doped graphene oxide (NG) supported ZnWO4 nanocuboids as an efficient catalyst for photoelectrochemical MOR and electrochemical ORR. Under visible light (420 nm), the NG/ZnWO4 nanohybrid exhibits exceptional photoelectrochemical MOR with low potential of 0.5V with a high oxidation peak current density of ?10 mA cm?2 is recorded while comparing with benchmark catalyst Pt/C. In two electrode systems for DMFC, the catalyst reaches an impressive maximum power production of 111 mW cm?2 with very stable charge?discharge cycles of 0.33 mV cycle?1, which is far superior to ZnWO4’s alone. Simultaneously, the nanocomposite exhibits excellent ORR activity in alkaline medium with improved onset half?wave potential of 0.85V, high current density of 5.8 mA cm?2 at 1600 rpm, and robust stability, attributed to the synergistic effect between NG and ZnWO4. This work has reinforced these findings with theoretical insights using the Vienna Ab initio Simulation Package (VASP) to assess both PMOR and ORR performance and reaction intermediates.

Three perovskite halide solar cell device models are proposed and simulated using SCAPS-1D software to explore their performance and potential for practical application. Device 1 features a double-absorber-layer hetero-junction structure combining CsGeI3 and CsGeI2Br, while Devices 2 and 3 utilize single absorber layers of CsGeI2Br and CsGeI3, respectively. Spiro-OMeTAD and ZnO were employed as the hole and electron transport layer, respectively, in all three structures. Density functional theory (DFT) was used to study the suitability of CsGeI2Br and CsGeI3 as absorber layers in the proposed device models. Then comprehensive optimization of critical device parameters including absorber layer thickness, defect density, interface defect density and operating temperature were performed to enhance device performance. After optimization, Device 1 demonstrated a significant power conversion efficiency of 21.51%, outperforming Devices 2 and 3 which achieved efficiencies of 16.66% and 15.95% respectively. The superior performance of Device 1 highlights the potential advantages of a double-absorber-layer configuration in improving light absorption and charge carrier dynamics. These results provide a solid foundation for further experimental investigations and feasibility of CsGeI3 and CsGeI2Br-based perovskite structures in the development of high-efficiency solar cells.

Earth?abundant transition metal?based catalysts with exceptional bifunctionality for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are greatly desired. Alloyed catalysts, such as molybdenum?nickel (MoNi), are known to demonstrate enhanced HER activity, yet suffer from low OER performance. To realize improved functionality, elemental doping can be an effective approach, giving rise to synergistic interactions between incorporated metal species, optimizing surface adsorption of target intermediates, and promoting reaction. Herein, the enhanced OER performance of the MoNi catalyst while simultaneously boosting HER activity via incorporating a small amount of iron and chromium into MoNi (Mo?Ni(FeCr)) is demonstrated. For an optimized Mo?Ni(FeCr) catalyst, in 1.0 m potassium hydroxide electrolyte, an overpotential of only 11 and 179 mV for HER and OER, respectively, are required to afford a current density of 10 mA cm?2. For the overall water splitting, a current density of 20 mA cm?2 is reached at 1.489 V. The DFT calculations demonstrated that the inclusion of Fe and Cr in a molybdenum?nickel catalyst reduced the limiting potentials for both OER and HER, unlocking efficient bifunctionality activity for water splitting. These findings signify the improved electrocatalytic performance of, amongst the most active bifunctional electrocatalysts.

The electrocatalytic CO2 reduction reaction (CO2ER) has sparked immense interest due to its potential to generate valuable multi-carbon (C2) products. The innovative dual active site catalysts (DACs) feature dual-atom sites that create the perfect geometric environment for two CO molecules to bond simultaneously. In this study, we spotlight transition metal (TM) dimers anchored on nitrogen-doped graphene, referred to as TM1TM2@NGr, as our primary focus. Analysing 54 candidates, we evaluate their stability via negative binding energy and ICOHP values, enhanced by ab initio molecular dynamics (AIMD) calculations. Three systems namely WIr@NGr, WFe@NGr, and WW@NGr demonstrate remarkable selectivity for ethanol production due to their low free energy difference (?G*CO dimer–2*CO) which offers low overpotentials of 0.47, 0.49, and 0.5 V, respectively. We analysed 71 electronic parameters to identify key factors influencing the free energy difference (?G*CO dimer–2*CO) and found 12 electronic descriptors strongly correlated due to the Pearson correlation coefficient (r) being larger than 0.8. Among these, the occupancy of the dxz orbital (dxz_occ) and the downward channels of dxz and dz2 orbitals (dxz_down_occ and dz2_down_occ) were the most effective for predicting the energy difference, demonstrating the highest r values. This highlights their importance as key descriptors for ?G*CO dimer–2*CO and corresponding C2 production. Furthermore, three DACs have been identified as highly effective for hydrogen evolution reactions (HER), while thirteen DACs show CO2ER to methane production. Our research offers vital insights into the catalytic mechanisms of DACs, paving the way for discovering cost-effective candidates for efficient CO2 conversion into valuable C2 products.

Glycerol, a by?product of biodiesel production, and CO2, a major greenhouse gas, are abundant but underutilized feedstocks. Their simultaneous conversion into formic acid and lactic acid presents an innovative and sustainable approach to addressing environmental challenges. Formic acid, a versatile compound in multiple industries, and lactic acid, a versatile platform chemical used in food, pharmaceuticals, and biodegradable plastics, hold immense commercial value. In this work, a NiO?ZrO2 catalyst synthesized through incipient wetness impregnation is employed to achieve the simultaneous conversion of CO2 and glycerol in an alkaline medium. Comprehensive characterisation of the catalyst using PXRD, Raman spectroscopy, XPS, BET surface area, CO2/NH3?TPD, H2?TPR, and UHR?TEM analysis revealed its unique properties, including weak Lewis acid sites critical to its performance. Under optimal reaction conditions, 200 °C, 40 bar CO2, and KOH as the base, the catalyst achieved yields of 3.26 mmol of formate and 11.20 mmol of lactate. The synergistic interaction between NiO and ZrO2, along with the in situ formation of carbonate salts, is key to the high efficiency. An initial economic assessment demonstrates the commercial viability of co?producing formic and lactic acid, with the glycerol price and the efficiency of converting the formate and lactate salts to the corresponding acids being critical factors for the economic feasibility of the process.

This study highlights K2Tl(As/Sb)I6 as a thermodynamically stable, lead-free double perovskite with exceptional bifunctional photovoltaic and thermoelectric performance, making it a promising candidate for next-generation clean energy applications. We have explored the structural, optoelectronic and thermoelectric properties by using DFT while their photovoltaic properties have been explored with the help of SCAPS-1D simulations. The predicted negative formation energy and the lower fluctuation in RMSD obtained through DFT calculations, indicates that K2Tl(As/Sb)I6 is thermodynamically stable. Furthermore, electronic property analysis using the TB-mBJ method reveals that both K2TlAsI6 and K2TlSbI6 possess a desirable direct band gap of 1.16 eV and 1.04 eV, respectively—ideal for optoelectronic applications. The optical analyses unveil remarkable absorption coefficients, soaring to the impressive magnitude of 10? cm?¹, beyond the threshold energy of 1.18 eV for K2TlAsI6 and 1.05 eV for K2TlSbI6. These compounds exhibit notable electrical conductivity and minimal reflectivity, attributed to their well-dispersed band structures and optimally aligned band gap values. The thermoelectric evaluation highlights exceptional ZT values of 0.79 and 0.74 at 510 K for K2TlSbI6 and K2TlAsI6, respectively, owing to their ultra-low thermal conductivity (??/?~1014 W m?1?1 s?1) and remarkably high electrical conductivity (?/?~1019 ? m?1 s?1) over a wide temperature range of 200–650 K. Furthermore, SCAPS-1D simulations unveil outstanding photovoltaic performance, showcasing peak power conversion efficiencies of 30.01% (31.77%) for Ag/Cu2O/K2TlAsI6/TiO2/FTO (Ag/Cu2O/K2TlSbI6/TiO2/FTO), with corresponding JSC values of 40.69 mA/cm2 (45.07 mA/cm2), VOC of 0.93 V (0.81 V), and fill factors of 84.07% (82.21%). These remarkable figures surpass those of recently reported lead-free halide double perovskite solar cells, driven by the excellent electronic and optical characteristics of K2Tl(As/Sb)I6. This study provides a promising pathway toward the realization of next-generation high-efficiency solar cells and thermoelectric devices based on eco-friendly materials

A significant research gap in the field of synthesis of single atom catalysts (SACs) is addressed by developing a low-temperature complexation approach to stabilize the single metal atoms on stacked polytiazine matrix (g-C3N4) with a good metal loading. Unlike conventional high-energy (400-700 °C) and time-intensive (120-300 min) methods typically used for embedding SACs in g-C3N4 matrices, the present synthesis utilizes a facile, microwave-assisted method that operates at a low temperature of 140 °C and completes within 30 min. Comprehensive analysis reveal that complexation of the Cu2+/Cu+ ions with nitrogen in the polytriazine structure facilitates layer stacking. Specifically, Cu? ions promote sheet formation in co-ordination with two nearby N atoms, while Cu2+ ions stabilize the stacked layers of the polytriazine framework through co-ordination with four N atoms. The resulting SAC exhibits a Cu metal loading up to 3.5 wt.%, with a specific surface area (SABET) of 330 m2 g-1 and pore size distribution centered at 1.9 and 5 nm. The SAC demonstrates excellent catalytic performance for click cycloaddition reactions under base-free conditions, with a high turnover frequency (TOF) of 120 h-1, a broad substrate scope, and reusability across seven cycles without detectable Cu leaching, making it a promising SAC for triazole synthesis

Indoor photovoltaic (IPV) cells are designed to operate under low-intensity artificial light sources. Generally, artificial light sources have a narrow spectrum, which can be efficiently captured by a wide band gap absorber. However, existing wide band gap absorbers, such as amorphous silicon (a-Si), perovskite (MAPbX3), suffer from toxicity and stability issues, making it essential to explore an alternative that is an earth-abundant, environmentally friendly. In this study, we used Vienna ab initio Simulation Package (VASP)-based ab-initio calculations to investigate Cu2BaSnS4 (CBTS) materials, focusing on their crystal structure, optoelectronic properties, and performed SCAPS-based simulations for performance estimation. CBTS exhibits a direct band gap ( E g ) of ?1.9 eV and high absorption coefficient (? ? 105 cm?1) in the UV-visible spectrum, making it ideal for IPV applications. Detailed balance calculations predict remarkable solar cell efficiencies of 59.96% ( E g = 1.9 eV) and 57.51% ( E g = 1.95 eV) under indoor light emitting diode (LED) and compact fluorescent light (CFL) lighting. The simulated efficiency exceeding 50% are attributed to the narrow emission spectrum of indoor light sources, which is efficiently absorbed by wide band gap CBTS. Key factors influencing efficiency include high shunt resistance (RSh > 106 ? cm2) and minimal impact of series resistance up to 100 ? cm2. A key distinction between IPV and outdoor photovoltaics is the lower photo-generated carrier concentration in low-light conditions, leading to a higher ratio of trapped to photo-generated carriers. These findings highlight CBTS’s potential for next-generation indoor energy solutions.

Perovskite solar cell technology approaches the brink of commercialization, the issue of organic materials and toxic remains a concern. CsSnI3, with its eco-friendly nature, optimal 1.3 eV band gap, high carrier mobility, and Sn-enhanced stability, stands out as a promising alternative. However, its experimental efficiency is hindered by issues like energy band misalignment, high carrier concentration, and defects. In this work, we present a modification to the structure of a CsSnI3/TiO2 solar cell to tackle its low experimental efficiency. This proposed design focuses on achieving optimal energy band alignment and reducing bulk recombination by optimizing the band gap, conduction band offset, carrier mobility, and defect density within the absorber bulk. Additionally, it aims to mitigate interfacial recombination by inserting a thin intrinsic layer at the CsSnI3/TiO2 interface. The modifications to the CsSnI3 solar cell architecture have significantly increased its efficiency to 24.54%, up from the previously reported 12.96%

Halide perovskites have emerged as leading contenders for next-generation photovoltaic (PV) technology, offering exceptional optical properties, high efficiency, lightweight design, and cost-effectiveness. This study unveils a cutting-edge numerical approach to enhance efficiency in a novel dual-absorber perovskite solar cell (PSC), harnessing eco-friendly inorganic perovskite materials and precise parameter optimization. Initially, we performed comprehensive first-principles calculations of KSnI3 and CsSnI3, revealing their unique direct band gap characteristics of 1.82 eV and 1.26 eV, respectively. Both materials exhibit exceptional absorption coefficients exceeding 105 cm-1 beyond their band gaps, alongside minimal lattice mismatch, making them prime candidates for next-generation high-performance dual-absorber solar cells. In our proposed PSC architecture, KSnI3 acts as the upper absorber layer, while CsSnI3 serves as the lower absorber, complemented by ZnMgO as the electron transport layer (ETL) and NiOx as the hole transport layer (HTL). By utilizing double-graded KSnI3/CsSnI3 materials, our study achieves an impressive efficiency of 30.01%, with an open circuit voltage of 1.11 V, fill factor of 78.1%, and short circuit current of 37.76 mA/cm2. The simulation comprehensively examines the influence of absorber and transport layer thickness, as well as bulk and interface defect densities, on the device’s performance parameters. Additionally, it evaluates the effects of series and shunt resistances and investigates temperature variations to assess performance stability. These insights pave the way for the design and development of next-generation, high-efficiency dual-absorber solar cells

The recent year has witnessed a flurry of activities in investigating the promising electronic, optical, and transport properties of lead-free double perovskite halides. In the present work, the structural, electronic, optical, and transport properties of Cs2(Li/Na)GaI6 are carefully examined. The predicted negative formation energy, absence of imaginary frequency in the phonon spectra, and ab-initio molecular dynamics calculations show that they are thermodynamically stable. Additionally, electronic studies employing generalized gradient approximation (GGA)–Perdew–Burke–Ernzerhof (PBE) + modified Becke-Johnson + spin-orbit coupling reveal that Cs2(Li/Na)GaI6 exhibits a direct bandgap, with values of 1.24 eV for Cs2LiGaI6 and 1.39 eV for Cs2NaGaI6. The exceptional optical properties, including a high absorption coefficient (105 cm?1) and excellent optical conductivity with low reflectivity across the entire UV–visible range, indicate that Cs2(Li/Na)GaI6 are promising materials for solar cell applications. Moreover, the ultralow thermal conductivity, high Seebeck coefficient, and substantial electrical conductivity of Cs2(Li/Na)GaI6 result in a high figure of merit over the temperature range of 200–600 K. Thus, Cs2(Li/Na)GaI6 shows strong potential as both photovoltaic and thermoelectric materials. © 2024 Wiley-VCH GmbH.

Lead-free double perovskite halides are attracting considerable interest in the optoelectronics sector due to their remarkable electronic, optical, and transport properties. These materials are not only stable and easy to synthesize but also present a wide range of potential applications. This study investigates the fascinating characteristics of Rb?LiGa(Br/I)?, focusing on its structural, electronic, optical, transport, and photovoltaic attributes. Our findings indicate that Rb?LiGaBr? and Rb?LiGaI? have band gaps of 1.19 eV and 1.13 eV, respectively, highlighting their versatility for various applications. Both compounds exhibit exceptional optical properties, featuring high absorption coefficients and optical conductivity, along with low reflectivity throughout the UV-visible spectrum, positioning them as excellent candidates for solar cell technologies. Moreover, Rb?LiGa(Br/I)? demonstrates impressive thermoelectric performance, with high figure-of-merit (ZT) values between 200 K and 800 K, indicating their potential as effective thermoelectric materials. Consequently, this study offers valuable insights for the development of efficient double perovskite-based solar cells. Encouraged by the outstanding absorption and optical conductivity of Rb?LiGa(Br/I)?, we simulated an Au/Cu?O/Rb?LiGa(Br/I)?/TiO?/FTO solar cell. Our results reveal that the modeled solar cell, Au/Cu?O/Rb?LiGaI?/TiO?/FTO, achieves an efficiency of 26.48%, surpassing previous reports. This research sets a new benchmark for high-performance double perovskite-based solar cells and lays the foundation for future advancements in this exciting area.

Enhancing the efficiency of solar cells depends on minimizing reflection losses to boost photon absorption. In this study, we investigated the chemical etching process of pristine InP(100), (named as pris-InP(100)). Our findings demonstrate that the etching process resulted in a self-organizing V-groove microstructure, as revealed by atomic force microscopy and scanning electron microscopy. This induced V-groove microstructure resulted a significant reduction in the reflection loss. Through temporal variation in the etching process, we identified that a 5-minute etch (named as etch5-InP(100)), yielded the lowest reflectance. Additionally, radiofrequency (RF) magnetron sputtering was employed to deposit a 10 nm Nb2O5 thin film on both pris-InP (100) and etch5-InP (100) samples. The results indicated that the thin film on etch5-InP(100) exhibited significantly lower reflectance compared to pris-InP(100). Moreover, ab-initio calculations verified the stability and presence of native oxide at the interface of the Nb2O5/InP(100) heterostructure. Furthermore, dark current-voltage (I-V) characteristics indicated typical diode behaviour for both Nb2O5 thin films deposited on pris-InP(100) and etch5-InP(100). Notably, light I-V measurements revealed that the Nb2O5 thin film on etch5-InP(100) achieved a higher efficiency of 11.6% compared to the 8.7% efficiency of pris-InP(100). This study provides valuable insights and guidelines for the development of high-efficiency InP-based solar cells.

Ion migration in mixed halide perovskite (MHP) absorber layers limits the long-term stability of wide-band gap (WBG) solar cells, posing a challenge to commercialization. We address this challenge with an “ionic lockdown” strategy using a vinyl imidazolium–iodine couple, [VIm][I], at the device interface. The iodine counterion effectively occupies surface iodide vacancies, suppressing ion migration. This treatment neutralizes native defects and locks volatile iodide and organic cations, as evidenced by an increase in defect formation energies by ?0.8 eV and activation energy for ion migration by ?0.59 eV. We demonstrate this with MAPb(I0.5Br0.5)3, a highly unstable MHP composition. In situ GIWAXS under AM1.5G at 85 °C shows no peak splitting, confirming the photostability. Devices treated with [VIm][I] retain 90% power conversion efficiency (PCE) under continuous illumination and recover 99% PCE in the dark. These results highlight the potential of [VIm][I] for enhancing the stability of WBG cells across different compositions, paving the way for more durable perovskite-based photovoltaic technologies.

Perovskite solar cells (PSCs) are improving in efficiency, but their stability remains a challenge compared to other solar technologies due to the use of hybrid organic–inorganic materials. To overcome this, researchers have shifted focus from methylammonium-based PSCs to more stable cesium (Cs)-based PSCs. By optimizing multi-layer structures to enhance solar spectrum absorption, substantial performance improvements are possible. In this study, we explored single (CsPbIBr2), dual (CsPbIBr2/KSnI3), and triple (CsPbIBr2/KSnI3/MASnBr3) absorber layer designs. The optimization of bilayer and triple-layer PSCs takes into account various factors, such as absorber layer thickness, defect density, and interface defect density for each PSC type. Finally, using the optimal triple-absorber layer combination, we optimized the electron transport layer, hole transport layer, series resistance, and shunt resistance. In this research, we attained impressive efficiencies of 34.22% for the triple-layer solar cell, 20.41% for the bilayer solar cell, and 7.32% for the single-junction PSC. This design approach led to an optimal configuration that showed substantial improvements over the experimental benchmark, including a 7.08% increase in open circuit voltage, a 256.9% increase in short circuit current, a 22.32% increase in fill factor, and a 367.5% increase in efficiency. By meticulously aligning multiple absorber layers in perovskite solar cells, we can unlock new pathways to developing highly efficient solar cells for the future.

As the world accelerates its shift toward cleaner, renewable energy, the pursuit of cost-effective, eco-friendly, and highly efficient thin film photovoltaics (TFPV) has become more urgent than ever. In this race, copper antimony sulfide (CuSbS2) stands out with its high absorption coefficient, abundant availability, and low cost making it a suitable candidate for use as a thin-film absorber layer. However, CuSbS2 solar cells currently achieve only around 3% efficiency, which is far from sufficient. The challenges lie in improper band offsets, high defect densities in the absorber layer, and suboptimal back metal contacts, all of which hinder the efficiency of CuSbS2 (CAS) solar cells. In this work, the structural, electronic and optical properties of the CuSbS2 absorbing layer were thoroughly examined through formation energy, band structure, density of states calculations and absorption coefficient. These analyses reveal that CuSbS2 is a highly promising photovoltaic material, thanks to its optimal direct electronic band gap. The initial simulations closely matched experimental results, providing a solid foundation for further analysis. Optimizing conduction and valence band offsets, along with the thickness and carrier density in the buffer and hole transport layers, led to an impressive efficiency jump from 3.22% to 9.56%. This study delved into how the thickness, carrier density, and defect concentration in the bulk absorber affect photovoltaic performance, uncovering vital correlations that boost efficiency. Finally, fine-tuning the series and shunt resistance and optimizing the back contact work function resulted in a dramatic improvement, achieving an impressive overall efficiency of 19.23%.