Recombination Rate Research Articles

Visible-light driven S-scheme Bi2WO6/graphitic carbon nitride heterojunction for efficient simultaneous removal of TC and Cr(VI)

The application of photocatalysts in water governance has attracted extensive attention, and past research efforts often focused on single pollutant removal. Simultaneous removal of multiple pollutants from wastewater by a single processing unit is highly desirable, realistic, and challenging. The use of band-matched semiconductors to form heterojunctions is an important way to achieve this technology. In this work, we have designed a Bi2WO6/g-C3N4 heterojunction via an in-situ growth method. The in-suit XPS was used to verify the electron transfer pathway which conforms to the S-scheme mechanism. Under visible light irradiation, the removal rates of Cr(VI) and TC are 97.7 % and 96.0 % respectively. In addition to the excellent photocatalytic performance, the catalyst showed a high degree of stability during the five cycles. The formation mechanism of S-scheme heterojunction is discussed based on DFT calculation and physicochemical characterization. Liquid chromatography-mass spectrometry (LC-MS) and Quantitative Structure-Activity Relationship (QSAR) were used to analyze and predict the degradation pathways, intermediates, and toxicity. The efficient performance of the photocatalyst is attributed to the more efficient photogenerated charge transfer efficiency brought about by the formation of the built-in electric field, and the improvement of the photogenerated carrier recombination rate to provide more reactive sites with a large specific surface area. We provide a practicable strategy for the efficient treatment of inorganic and organic co-pollutants in environmental water by constructing an S-scheme heterojunction photocatalyst.

Sulfur vacancy-rich ZnS on ordered microporous carbon frameworks for efficient photocatalytic CO2 reduction

ZnS has garnered significant attention as a versatile photocatalyst in the field of CO2 reduction. However, its photocatalytic efficiency has been hindered by its high charge recombination rates and sluggish reaction kinetics. Herein, we demonstrate a highly efficient CO2 photoreduction on well-designed S-deficient ZnS nanoparticles within an ordered mesoporous N-doped carbon framework (Vs-ZnS/OMNC) through an in situ thermal treatment strategy. The fs-TA spectrum elucidated that introducing sulfur vacancy (Vs) effectively promoted the separation of photogenerated charges in ZnS/OMNC and significantly improved its reaction kinetics. In situ DRIFTS spectroscopy and DFT calculations revealed that these S vacancies led to charge accumulation on neighboring Zn atoms, enabling effective adsorption and activation of CO2 molecules. Particularly, the vacancy strategy also effectively lowered the energy barrier for forming the key intermediate *COOH. Therefore, the CO evolution rate of Vs-ZnS/OMNC reached 712.1 μmol·g−1·h−1, which is 2.84 times higher than that without sulfur vacancy (250.74 μmol·g−1·h−1). Its CO2 reduction performance surpassed most ZnS-based photocatalysts reported previously. Additionally, the Vs-ZnS/OMNC exhibited outstanding stability without obvious degradation after five reaction cycles. This study provides insights into developing advanced photocatalysts through vacancy defect engineering combined with ordered mesoporous carbon structures.

Carbon Nanotube-Phenyl Modified g-C3N4: A Visible Light Driven Efficient Charge Transfer System for Photocatalytic Degradation of Rhodamine B.

In this study, we report the synthesis and characterization of a novel photocatalyst composite composed of functionalized carbon nanotubes (f-CNT) and phenyl-modified graphitic carbon nitride (PhCN). The incorporation of the phenyl group extends the absorption range into the visible spectrum compared to pure g-C3N4. Additionally, the formation of the heterostructure in the f-CNT/PhCN composite exhibits improved charge transfer efficiency, facilitating the separation and transfer of photogenerated electron-hole pairs and reducing recombination rates. The photocatalytic performance of this composite was evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation. The f-CNT/PhCN composite exhibits remarkable efficiency in degrading RhB, achieving 60% degradation after 4 h, and 100% after 24 h under low-power white LED excitation. This represents a substantial improvement over the non-functionalized CNT/PhCN composite, which shows much lower performance. In contrast, pure PhCN demonstrates very little activity. Structural and optical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, and UV-Vis spectroscopy. Time-resolved photoluminescence measurements were used to study the behavior of photoexcited carriers, confirming that the composite improves charge transfer efficiency for photogenerated carriers by approximately 30%. The results indicate that the functionalization of CNTs significantly enhances the photocatalytic properties of the composite, making f-CNT/PhCN a promising candidate for environmental remediation applications, particularly in the degradation of organic pollutants in wastewater.

Investigations on interfacial complex dynamic processes of Er-BiFeO3 based perovskite solar cell heterostructures

In the present investigations, we critically examine the response of thickness variation of the photoactive layer on I-V characteristics of the final optimized Er-doped BiFeO3 (Er-BF) designed devices (Er: 0 %, 4 %, 8 %, and 12 %). The recombination rate, energy band diagrams obtained at a final simulated thickness of the absorber and at the back contact metal work function were investigated for the purpose of barrier formation analysis. To establish the presence of deep defects in the perovskite based heterostructure devices, the measurements of respective designed devices related to capacitance–voltage (C-V), Mott-Schottky (MS) (1/C2-V), and conductance-voltage (G-V) characteristics were thoroughly performed and examined. The change in capacitance (or dielectric constant) induced thermally in the respective designed devices was investigated with the temperature-dependent capacitance-frequency (C-f) characteristics performed under the illumination and dark conditions, respectively. Further, the voltage dependent Nyquist plots were studied. Overall, this work provides critical insights into the impedance response of doped BiFeO3 absorber-based designed perovskite solar cells (PSCs) with cell structure FTO/ZnO/Er-BF/Spiro-OMeTAD/Au. It further facilitates the understanding of various complex electrical processes taking place at the different interfaces during the device operations which are significant for the better optimization and play crucial role in enhancing the overall photovoltaic performance of PSCs.

One-step synthesis of needle-like lanthanum-doped TiO2 nanomaterials and their photoconductivity activity in air medium

In this study, lanthanum-doped titanium dioxide (La-doped TiO2) was synthesized and characterized for the photoconductivity study in an air medium. TiO2 is well-known semiconductor with excellent optical and electrical properties, making it ideal candidate for optoelectronics applications. However, the incorporation of rare-earth element like La can significantly alter its performance, particularly under light exposure. Further, in this study, the effect of annealing was also carried out. The photosensitivity of La-doped TiO2 sample annealed at 600 °C shows better photosensitivity as compared to other samples. This enhancement is attributed to the increased carrier concentration and reduced recombination rates of photo-generated electron-hole pairs due to doping of lanthanum. These findings suggest that La-doped TiO2 holds potential for applications in photodetectors, UV sensors, and other optoelectronic devices operating in ambient conditions.

The recombination landscape of the barn owl, from families to populations.

Homologous recombination is a meiotic process that generates diversity along the genome and interacts with all evolutionary forces. Despite its importance, studies of recombination landscapes are lacking due to methodological limitations and limited data. Frequently used approaches include linkage mapping based on familial data that provides sex-specific broad-scale estimates of realized recombination and inferences based on population LD that reveal a more fine scale resolution of the recombination landscape, albeit dependent on the effective population size and the selective forces acting on the population. In this study, we use a combination of these two methods to elucidate the recombination landscape for the Afro-European barn owl (Tyto alba). We find subtle differences in crossover placement between sexes that leads to differential effective shuffling of alleles. LD based estimates of recombination are concordant with family-based estimates and identify large variation in recombination rates within and among linkage groups. Larger chromosomes show variation in recombination rates, while smaller chromosomes have a universally high rate which shapes the diversity landscape. We find that recombination rates are correlated with gene content, genetic diversity and GC content. We find no conclusive differences in the recombination landscapes between populations. Overall, this comprehensive analysis enhances our understanding of recombination dynamics, genomic architecture, and sex-specific variation in the barn owl, contributing valuable insights to the broader field of avian genomics.

Predicting Long-Term Stability from Short-Term Measurement: Insights from Modeling Degradation in Perovskite Solar Cells during Voltage Scans and Impedance Spectroscopy.

A drift-diffusion model is used to investigate the effect of device degradation on current-voltage and impedance measurements of perovskite solar cells (PSCs). Modifications are made to the open-source drift-diffusion software IonMonger to model degradation via an increasing recombination rate during the course of characterization experiments. Impedance spectroscopy is shown to be a significantly more sensitive measure of degradation than current-voltage curves, reliably detecting a power conversion efficiency drop of as little as 0.06% over a 4 h measurement. Furthermore, we find that fast degradation occurring during impedance spectroscopy can induce loops lying above the axis in the Nyquist plot, the first time this experimentally observed phenomenon has been replicated in a physics-based model.

Genomic Architecture Underlying the Striking Colour Variation in the Presence of Gene Flow for the Guinan Toad-Headed Lizard.

How divergence occurs between closely related organisms in the absence of geographic barriers to gene flow stands as one of the long-standing questions in evolutionary biology. Previous studies suggested that the interplay between selection, gene flow and recombination strongly affected the process of divergence with gene flow. However, the extent to which these forces interact to drive divergence remains largely ambiguous. Guinan toad-headed lizards (Phrynocephalus guinanensis) in the Mugetan Desert exhibit striking colour differences from lizards outside the desert and provide an excellent model to address this question. Through extensive sampling and whole genome sequencing, we obtained genotypes for 191 samples from 14 populations inside and outside the desert. Despite the colour differences, continuous and asymmetric gene flow was detected across the desert border. More importantly, 273 highly diverged regions (HDRs) were identified between them, accounting only for 0.47% of the genome but widely distributed across 20 (out of the total 24) chromosomes. Strong signatures of selection were identified in HDRs, and local recombination rates were repressed. Furthermore, five HDRs exhibited significantly higher divergence, which contained key genes associated with crucial functions in animal coloration, including pteridine and melanocyte pigmentation. Genes related to retinal cells and steroid hormones were identified in other HDRs, which might have also contributed to the formation of colour variation in the presence of gene flow. This study provided novel insights into the understanding of the evolutionary mechanisms of genetic divergence in the presence of gene flow.

Enhanced persulfate-assisted photocatalytic degradation of phenol by Ag/ZnFe2O4 composite

Effective and reasonable degradation of phenolic wastewater has important practical significance in reducing environmental pollution and ensuring water resource security. Ag/ZnFe2O4 (Ag/ZFO) photocatalysts were synthesized using the one-step solvothermal method and characterized by XRD, SEM, TEM, FT-IR, XPS, UV–vis DRS, and so on. Their photocatalytic performance for phenol degradation under visible light, assisted by persulfate (PS), was studied. The incorporation of Ag nanoparticles into ZFO significantly enhanced phenol degradation efficiency, especially 10 %Ag/ZFO showing the most remarkable improvement with 94.3 % phenol degradation in 60 min, —48.7 % higher than pure ZnFe2O4. The influence of various variables, including PS dosage, initial phenol concentration, solution pH, and common inorganic anions in water, on phenol degradation were examined systematically. The superior persulfate-assisted photocatalytic performance of 10 %Ag/ZFO, assisted by PS for phenol degradation, is primarily due to the surface plasmon resonance (SPR) effect of Ag nanoparticles, enhancing light absorption and use while inhibiting the photogenerated carriers’ recombination rates. In addition, Ag nanoparticles and the Fe3+/Fe2+ recycling redox process activate PS to produce more free radicals, thus improving the performance of the Vis-10 %Ag/ZFO-PS system for phenol degradation. The possible mechanism of the Vis-10 %Ag/ZFO-PS system for phenol degradation is described based on trapping tests, EPR, and XPS results. Magnetic retrievability, good structural stability, and high activity of the synthesized Ag/ZFO photocatalyst elucidate its potential application for degradation of phenolic wastewater.

Declining genetic polymorphism of the C-terminus Merozoite Surface Protein-1 amidst increased Plasmodium knowlesi transmission in Thailand

BackgroundRecent reports from Thailand reveal a substantial surge in Plasmodium knowlesi cases over the past decades, with a more than eightfold increase in incidence by 2023 compared to 2018. This study investigates temporal changes in genetic polymorphism associated with the escalating transmission of P. knowlesi malaria in Thailand over time using the prominent vaccine candidate, pkmsp1 as a marker.MethodsTwenty-five P. knowlesi samples collected in 2018–2023 were sequenced for the 42-kDa region of pkmsp1 and compared with 24 retrieved sequences in 2000–2009, focusing on nucleotide diversity, natural selection, recombination rate, and population differentiation.ResultsSeven unique haplotypes were identified in recent samples, compared to 15 in earlier samples. Nucleotide and haplotype diversity were lower in recent samples (π = 0.016, Hd = 0.817) than in earlier samples (π = 0.018, Hd = 0.942). Significantly higher synonymous substitution rates were observed in both sample sets (dS–dN = 2.77 and 2.43, p < 0.05), indicating purifying selection and reduced genetic diversity over time. Additionally, 8 out of 17 mutation points were located on predicted B-cell epitopes, suggesting an adaptive response by the parasites to evade immune recognition. Population differentiation analysis using the fixation index (Fst) revealed high genetic differentiation between parasite populations in central and southern Thailand or Malaysia. Conversely, the relatively lower Fst value between southern Thailand and Malaysia suggests a closer genetic relationship, possibly reflecting historical gene flow.ConclusionThis study highlights a decline in genetic diversity and evidence of purifying selection associated with the recently increased incidence of P. knowlesi malaria in Thailand. The minor genetic differentiation between P. knowlesi populations from southern Thailand and Malaysia suggests a shared recent ancestry of these parasites and underscores the need for coordinated efforts between the two countries for the elimination of P. knowlesi.

Study of the Photovoltaic Parameters of Inorganic Solar Cells Based on Cu&lt;i&gt;2&lt;/i&gt;O and CuO

A theoretical study of the photovoltaic parameters of inorganic solar cells based on ZnO/Cu2O and ZnO/CuO heterojunctions was carried out to improve the energy conversion efficiency. The influence of the thickness, charge carrier concentration and band gap of Cu2O and CuO films, as well as ZnO, on the photovoltaic parameters of solar cells has been studied. The simulation results showed that the efficiency of solar cells is significantly affected by the contact potential difference, the diffusion length of minority charge carriers, the amount of generated photocurrent and the recombination rate. The maximum efficiency of a solar cell based on ZnO/Cu2O was obtained equal to 10,63%, which is achieved with a band gap, thickness and charge carrier concentration in Cu2O equal to 1.9 eV, 5 μm and 1015 cm–3 and band gap, thickness and the concentration of charge carriers in ZnO is equal to 3,4 eV, 20 nm and 1019 cm–3, as well as the displacement of the edges of the conduction bands is 0.8 eV. For a solar cell based on ZnO/CuO, a maximum efficiency of 18.27% was obtained with a band gap, thickness and charge carrier concentration in CuO equal to 1.4 eV, 3 μm and 1017 cm–3, as well as a displacement of the conduction band edges of 0.03 eV. The obtained results of modeling solar cells can be used in the design and manufacture of inexpensive and efficient photovoltaic structures.

Studies of electron-ion resonant recombination of li-like Si11+ions

Abstract Theoretical investigations of L-shell △n = 0, 1, and 2 (2s → 2p, 3 l ′ , and 4 l ′ ) dielectronic recombination (DR), as well as K-shell △n = 1, 2, and 3 (1s → 2 l ′ , 3 l ′ , and 4 l ′ ) DR of Li-like Si 11+ ions are performed, using the relativistic distorted-wave approach. Detailed resonance energies, resonance strengths, and recombination rate coefficients are calculated including complex configuration mixing, Breit interaction, and QED corrections. Good agreement is achieved between the theoretical rate coefficients and the experimental results. The plasma rate coefficients are also calculated for electron temperatures ranging from 10−1 to 106 eV, and an analytical formula is presented to fit the total plasma rate coefficients for convenient modeling of astrophysical and fusion plasmas.

Piezoelectric effect promotes photoelectrochemical properties of 2D-3D ZnIn2S4/β-CdS strongly coupled interface

In the process of photoelectrochemical (PEC) hydrodecomposition, it is important to design photoelectrode materials with low cost, high charge separation efficiency and low charge recombination rate. Herein, 2D-3D strongly coupled ZnIn2S4/β-CdS nanocomposites were prepared by a two-step hydrothermal method. Meanwhile, the piezoelectric polarization was used to induce its generation of built-in electric field, which suppressed the secondary compounding of photogenerated charge carriers caused by the interfacial structural defects of the semiconductor heterojunction. The results show that ZnIn2S4/β-CdS has better photoelectrochemical decomposition ability of water under ultrasound, and its photocurrent density increases with the increase of ultrasound frequency, reaching a maximum value of 0.46 mA·cm−2 at 1.23 VRHE, which is 3.5 times higher than that before ultrasound. In addition, by comparing the significant increase of photocurrent conversion efficiency under the applied bias voltage before and after ultrasound, it can be concluded that the enhanced catalytic activity of ZnIn2S4/β-CdS is attributed to the efficient coupling effect between ZnIn2S4 and β-CdS under ultrasound conditions. This coupling effect enables the fast electron transfer at the interface between ZnIn2S4 and β-CdS. Consequently, this strongly coupled nanocomposite will provide inspiration for further construction of nanocomposites for photocatalytic decomposition of water.

Association of a non-synonymous variant of MLH3 gene involved in meiotic recombination with conception rate of Japanese Black cattle

Context Conception rate, which is an important parameter to evaluate female fertility, has been gradually decreasing in Japanese Black cattle during the past decades. Meiosis is an essential biological process in gamete formation and meiotic failure could be a cause of infertility or reduced fertility in mammals. Of note, single nucleotide polymorphisms (SNPs) in the MLH3 gene involved in meiotic recombination were reported to affect the genome-wide recombination rate of meiosis in cattle. Aims The present study was conducted to investigate the association of SNPs in the MLH3 gene with conception rate in Japanese Black cattle. Methods On the basis of the reproductive data of 2045 Japanese Black cattle born from 1990 to 2009, we selected two groups of the reproductive females with high conception rate (n = 103) and low conception rate (n = 109). Then, we genotyped the SNPs in MLH3 gene in both reproductive groups by sequencing and polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). The significant association of SNPs with conception rate in Japanese Black cattle was estimated by Fisher’s exact test, by using R commander. Key results We found the presence of five SNPs of MLH3 gene in Japanese Black cattle, including non-synonymous variants of MLH3 N408S that has been reported to be involved in meiotic recombination rate and MLH3 S591G newly identified in the present study. Comparison of genotype distributions and allele frequencies of the MLH3 N408S between high and low conception-rate groups indicated a significant difference between these groups, suggesting that this SNP is associated with conception rate. However, there is no significant difference between MLH3 S591G with conception rate in Japanese Black cattle. Conclusions We found a significant association between a non-synonymous variant of MLH3 N408S and conception rate, suggesting that this SNP can be a potential marker for selecting the Japanese Black cattle for improving fertility. We also identified a novel non-synonymous variant of MLH3 S591G in Japanese Black cattle. Implications These findings will be informative for future marker-assisted selection to improve the fertility of Japanese Black cattle. This is the first report of a genetic variant implicated in meiotic recombination being linked to female fertility in cattle.

Exploring Pt-Impregnated CdS/TiO2 Heterostructures for CO2 Photoreduction.

This work focuses on the production of methane through the photocatalytic reduction of carbon dioxide using Pt-doped CdS/TiO2 heterostructures. The photocatalysts were prepared using P25 commercial titania and CdS synthesized through a solvothermal methodology, followed by the impregnation of Pt onto the surface to enhance the physicochemical properties of the resulting photocatalysts. The pure and heterostructure-based materials were characterized using X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-Vis), ultraviolet photoelectron spectroscopy (UPS), and photoluminescence spectroscopy (PL). The obtained results show the successful synthesis of the heterostructure impregnated with Pt. Moreover, the observed key role of CdS and Pt nanoparticles in the final semiconductor is to reduce the electron-hole pair recombination rate by acting as an electron sink, which slows down the recombination process and increases the photocatalyst efficiency. Thus, Pt-doped CdS/TiO2 heterostructures with the best observed composition presents better catalytic activity than P25 titania with methane production values being 460 and 397 µmol CH4/g·h, respectively.

Energy Band Alignment and Defect Synergistic Regulation Enable Air-Solution-Processed Kesterite Solar Cells With the Lowest VOC Deficit.

The major challenge in preparing high-performance Cu2ZnSn(S,Se)4 solar cells is the large open circuit voltage deficit (VOC-def). A new strategy utilizing the synergistic substitution of Ag and In dual cations has been proposed to simultaneously address the problems of undesirable interface band alignment and high-density detrimental bulk defects, obtaining decreased carrier recombination rate and increased minority carrier lifetime. The shorter In-S/Se bonds move the CBM higher by generating stronger repulsive force than the Sn-S/Se bonds, thus adjusting the interface band alignment. Ag substitution can effectively suppress Cu─Zn disorder, while Ag, In dual substitution can further passivate Sn-related defects and solve the issue of low carrier concentration in Ag single-substituted samples. Besides, the superior carrier property of In-Se materials significantly enhanced the device carrier lifetime and minority carrier diffusion length. The state-of-the-art air-solution-processed CZTSSe device without any addition treatment with 14.33% efficiency and 580mV VOC is obtained, possessing the lowest VOC-def value currently available in the CZTSSe field (VOC/VOC SQ = 64.7%). This work emphasizes the synergistic modulation of band alignment, defect level, grain growth, and carrier transportation by dual cation substitution, which paves a convenient and effective way to realize high-performance solar cells and photovoltaic devices.

Synthesis of Photocatalyst Based on WO3 Applying for the Treatment of Tetracycline Antibiotics

In this paper, WO3/g-C3N4 photocatalysts were fabricated by ultrasonic-assisted hydrothermal method at different mole ratios of WO3/g-C3N4. Ultraviolet–visible absorption spectroscopy (UV-Vis DRS) and photoluminescence (PL) results indicated that WO3/g-C3N4 photocatalyst with the WO3/g-C3N4 mole ratio of 1/1 (WC-1) showed visible light absorption ability and prevented electron-hole recombination rate better than WO3, g-C3N4 and other composites. The photocatalytic activities of synthesized photocatalysts were investigated by the photocatalytic oxidation of tetracycline (TC) antibiotics under visible light. The degradation efficiency of TC in aqueous environment by the WC-1 was 79.35% after 180 minutes. This value was higher than those of other materials. The improvement in photocatalytic property of the WO3/g-C3N4 was due to the efficient generation of electrons and holes.

A whole-genome scan for evidence of recent positive and balancing selection in aye-ayes (Daubentonia madagascariensis) utilizing a well-fit evolutionary baseline model.

The aye-aye (Daubentonia madagascariensis) is one of the 25 most endangered primate species in the world, maintaining amongst the lowest genetic diversity of any primate measured to date. Characterizing patterns of genetic variation within aye-aye populations, and the relative influences of neutral and selective processes in shaping that variation, is thus important for future conservation efforts. In this study, we performed the first whole-genome scans for recent positive and balancing selection in the species, utilizing high-coverage population genomic data from newly sequenced individuals. We generated null thresholds for our genomic scans by creating an evolutionarily appropriate baseline model that incorporates the demographic history of this aye-aye population, and identified a small number of candidate genes. Most notably, a suite of genes involved in olfaction - a key trait in these nocturnal primates - were identified as experiencing long-term balancing selection. We also conducted analyses to quantify the expected statistical power to detect positive and balancing selection in this population using site frequency spectrum-based inference methods, once accounting for the potentially confounding contributions of population history, recombination and mutation rate variation, and purifying and background selection. This work, presenting the first high-quality, genome-wide polymorphism data across the functional regions of the aye-aye genome, thus provides important insights into the landscape of episodic selective forces in this highly endangered species.

Thickness and Doping Density Influence of a High-Voltage Inorganic Perovskite Solar Cell: A SCAPS 1-D Simulation Study

Recently, all inorganic perovskite solar cells have triggered great attention thanks to the rising performance during their development in solid state photovoltaics showing enhanced characteristics, such as: good stability, high photoluminescence quantum yield, tunable size, and morphology. In this work, a high open-circuit voltage solar cell based on all-inorganic perovskite through SCAPS simulator program is presented by analysing electron transport layer (ETL), perovskite layer, hole transport layer (HTL) thickness and doping density from a FTO/TiO2/CsPbBr3/Spiro-OMeTAD/Au structure were modified to observe its influence on solar cell performance. Therefore, simulation results show that a thicker ETL hinders carrier transport towards the FTO layer due to larger distance which leads to higher recombination rate, reducing carrier’s lifetime. Albeit high doping density values in ETL enhances the overall solar cell performance. As for the absorber layer, while its thickness increases, carrier collection rate decreases due to recombination impacting Voc, which results from thickness increase. Based on the results, solar cell efficiency improvement is attributed to the built-in electric field as absorber layer doping density increases. While HTL thickness has minimum impact on the solar cell output, doping density enhances device parameters significantly. Summarising the results obtained from thickness and doping density simulations, the optimal solar cell operation was obtained at 10 nm, 600 nm, and 100 nm layer thickness as well as 1020 cm-3, 1016 cm-3, and 1020 cm-3 doping density (TiO2, CsPbBr3 and Spiro-OMeTAD). Results from three different sources, collected from literature, were used to compare, and fitting them along with simulation results.

Optimizing Charge Separation and Transport: Enhanced Photoelectrochemical Water Splitting in α-Fe2O3/CZTS Nanorod Arrays

This study explores the enhancement of α-Fe2O3 (hematite) nanorod arrays for photoelec-trochemical applications by constructing a Cu2ZnSnS4 (CZTS) heterojunction. While α-Fe2O3 offers good stability, a low cost, and environmental benefits, its efficiency is limited by slow oxygen evolution kinetics, high carrier recombination rates, and low conductivity. By introducing CZTS, a material with strong light absorption and charge transport properties, we enhance the separation of photogenerated charge carriers, reduce charge transfer resistance, and increase the carrier concentration, thereby boosting the overall photoelectrochemical performance. The experimental results show that a modified FC-15 photoanode achieves a photocurrent density of 3.40 mA/cm2 at 1.60 V vs. RHE, a substantial increase compared to 0.40 mA/cm2 for unmodified α-Fe2O3. Band gap analysis reveals a reduced band gap in the FC-15 material, enhancing light absorption and boosting the photoelectrocatalytic performance. In photoelectrochemical water-splitting tests, the FC-15 photoanode achieves a hydrogen production rate of 41.6 μmol/cm2/h, which is significantly improved over the unmodified sample at 5.64 μmol/cm2/h. These findings indicate that the CZTS/α-Fe2O3 heterojunction effectively promotes charge separation, enhances charge transport, and improves light absorption, substantially increasing photocatalytic efficiency. This heterojunction approach offers new insights and technical strategies for developing photocatalytic materials with potential applications in renewable energy.