Electron Transport Research Articles

An analysis comparing the performance of lead and tin halides organic Perovskite Solar Cells and numerical simulation with SCAPS.

The scientific community focused on finding environmentally safe alternative metal halides to address the instability and toxicity associated with lead perovskite materials. These alternatives are supposed to replace lead halides without altering the distinctive properties of lead perovskite materials. Additionally, they should contribute to producing longer-lasting and stable perovskite in solar cells. This research presents a practical investigation of using tin- and lead-based composites in perovskite iodide solar cells with Titanium dioxide (TiO2) and Copper oxide (CuO) as electron transport materials (ETM) and hole transport materials (HTM), respectively. The performance parameters of the perovskite solar cells (PSCs) are compared with those of lead-based and lead-free PSCs with the same charge transport layers of ETM and HTM, as well as compare the practical results with the software results of Solar Cell Capacitance Simulation (SCAPS) package. In this study, the performance of PSCs with an absorption layer ((CH3NH3PbI3)t / (CH3NH3SnI3)1-t) was examined. The thickness of the perovskite layer is represented by (t), which can take the values( t = 1, 0.5, or 0) μm. The results of the laboratory study were compared to the performance of PSCs based on numerical analysis of SCAPS modeling. PSCs were prepared with a configuration structure (FTO / compact TiO2 / (CH3NH3PbI3)t/ (CH3NH3SnI3)1-t /CuO /Cu-electrode). A tetragonal phase was obtained for perovskite materials CH3NH3PbI3 and CH3NH3SnI3 with a direct optical energy gap estimated at (1.55 and 1.35) eV, respectively. The l-V curve of the prepared PSCs was studied, and the performance of the solar cells was examined under a light intensity of 100 mW/cm2. The power conversion efficiency, PCE, of the prepared solar cells, was (PCE = 2.9, 3.11, or 0.5) at (t = 1, 0.5, or 0)μm, respectively. A comparative analysis was also performed between the empirical performance of the manufactured PSCs and the theoretical results acquired by the SCAPS package software.

Modified SnO2 Electron Transport Layer by One‐Step Doping with Histidine in Perovskite Solar Cells

Tin dioxide (SnO2), one of the best electron transport layer materials for perovskite solar cells (PSCs), has high electrical conductivity and low photocatalytic activity. However, the defects in its inside and surface result in nonradiative recombination at the SnO2/perovskite interface. Complex and time‐consuming passivation methods are not conducive to the commercialization of PSCs, and simple passivation strategies should be used to improve the photovoltaic performance of the devices. Herein, a facile and efficient method is proposed to simultaneously passivate the inside and surface defects by adding histidine (HIS) to SnO2 colloidal solution. This one‐step doping strategy also modulates carrier dynamics at the SnO2/perovskite interface. HIS reduces suspended hydroxyl groups, oxygen vacancies, and uncoordinated Sn4+ defects on the surface of SnO2, as well as uncoordinated Pb2+ and halogen vacancy defects at the buried interface of perovskite. Surprisingly, HIS can prevent perovskite from decomposition to form PbI2, which further decomposes to photoactive metallic Pb0 and I, causing ion migration in PSC. As a result, the PSC efficiency has significantly improved 23.11% after HIS doping. The efficiency of unencapsulated device with HIS is 94% of the primary efficiency after storage in relative humidity = 70 ± 5% for 1000 h.

PVA-assisted spray deposited porous Li4Ti5O12 thin film as high-rate and long-cycle anode for lithium-ion thin-film batteries

Spinel Li4Ti5O12 (LTO), a zero-strain material, is a promising anode material for solid-state thin-film lithium-ion batteries (TFB). However, the preparation of high-performance Li4Ti5O12 thin-film electrodes through facile methods remains a significant challenge. Herein, we present a novel approach to prepare a binder- and conductor-free porous Li4Ti5O12 (P-LTO) thin-film. This approach polyvinyl alcohol (PVA)-assisted spray deposition and does not require the use of complex or expensive methods. Adding PVA to the precursor solution effectively prevents thin-film cracking during high-temperature annealing, enhances adhesion, and forms a highly interconnected porous structure. This unique structure shortens the lithium-ion diffusion pathways and facilitates electron transport. Therefore, P-LTO thin film electrodes demonstrate exceptional rate capacity of 104.1 mAh/g at a current density of 100C. In addition, the electrodes exhibit ultra-long cycle stability, retaining 80.9% capacity after 10,000 cycles at 10C. This work offers a novel approach for the preparation of high-performance thin-film electrodes for TFBs.

Utilization of doping and compositing strategy for enhancing the thermoelectric performance of CaMnO3 perovskite

The performance of high-temperature thermoelectric material CaMnO3 is primarily limited by its high electrical resistivity and thermal conductivity. In this study, we synergistically optimized its electrical and thermal transport properties by employing a combination of doping and compositing strategies. The results suggest that Yb doping promotes the transfer of electrons to the Mn d orbital and facilitates the double exchange interactions between neighbor Mn3+ and Mn4+, leading to decreased electrical resistivity and a transition of electron transport mechanism from semiconductor to metal. The further addition of CoAl2O4 nanoparticles improves the Seebeck coefficient by reducing carrier concentration and increasing electron scattering, ultimately enhancing the power factor. Meanwhile, the fluctuations in atomic mass and increased interface density strengthen the interface phonon scattering, which results in a significant reduction in lattice thermal conductivity. As a result, the Ca0.95Yb0.05MnO3 with 2 wt% CoAl2O4 nanoparticles exhibits a maximum ZT value of 0.12 at 850 K, representing a 180 % improvement compared to the pristine material. This study highlights the effectiveness of the combined doping and compositing strategy in enhancing the thermoelectric performance of CaMnO3 materials and offers a promising approach for optimizing other oxide thermoelectric materials.

Tanning wastewater restructured nitrogen-transforming bacteria communities and promoted N2O emissions in receiving river riparian sediments

Physicochemical and toxicological characterization of leather tanning wastewater has been widely documented. However, few reports have examined the response of denitrification N2 and N2O emissions in riparian sediments of tannery wastewater-receiving rivers. In this study, 15N-nitrate labeling was used to reveal the effects of tanning wastewater on denitrification N2 and N2O emission in a wastewater-receiving river (the old Mang River, OMR). OMR riparian sediments were highly polluted with total organic carbon (93.39 mg/kg), total nitrogen (5.00 g/kg) and heavy metals; specifically, Cr, Zn, Cd, and Pb were found at concentrations 47.3, 5.8, 1.6, 4.3, and 2.8 times that in a nearby parallel river without tanning wastewater input (the new Mang River, NMR), respectively. The denitrification N2 emission rates (0.0015 nmol N · g−1 · h−1) of OMR riparian sediments were significantly reduced by 2.5 times compared with those from the NMR (p < 0.05), but the N2O emission rates (0.31 nmol N · g−1 · h−1) were significantly increased (4.1 times, p < 0.05). Although the dominant nitrogen-transforming bacteria phylum was Proteobacteria in the riparian sediments of both rivers, 11 nitrogen-transforming bacteria genera in the OMR were found to be significantly enriched; five of these were related to pollutant degradation based on linear discriminant analysis (LDA > 3). The average activity of the electron transport system in the OMR was 6.3 times lower than that of the NMR (p < 0.05). Among pollution factors, heavy metal complex pollution was the dominant factor driving variations in N2O emissions, microbial community structure, and electron transport system activity. These results provide a new understanding and reference for the treatment of tanning wastewater-receiving rivers.

Enhancing oxygen reduction reaction of microbial fuel cells by core-double shell structure MnO2/NiFe-LDH@NiCo2S4 as cathode catalyst

Manganese dioxide (MnO2) and NiFe-layered double hydroxide (LDH) nanosheets were deposited on bimetallic metal sulfide (NiCo2S4) by hydrothermal reaction method, and MnO2/NiFe-LDH@NiCo2S4 was applied as cathode catalyst in microbial fuel cell (MFC). The combination of lamellar MnO2 with NiFe-LDH coated on NiCo2S4 achieved a typical core-double shell structure. The unique core-double shell structure created a rapid pathway for electron transport and reduced interfacial impedance. The MnO2/NiFe-LDH@NiCo2S4-MFC exhibited the maximum power density of 80 mW/m2, approximately 2.16 times that of the MnO2-MFC (37 mW/m2). Additionally, the maximum voltage was around 200 mV, with good stability maintained for approximately 10 d. The material exhibited excellent electrochemical properties and possessed great potential for application as cathode catalysts of MFC.

The introduction of rich active sites on 0D@2D nanocarbon via light illuminating with high-efficient electrocatalytic H2O2 production

Two-dimensional (2D) carbon-based materials are high-quality electrocatalytic materials with high mass transfer interfaces. However, the intrinsic 2D surfaces often lack of abundant active sites and outstanding electron transport channels. Herein, a 0D@2D nanocarbon material with affluent unsaturated oxygen-containing groups (UOCGSs) active sites and excellent electron channels are constructed via a novel sodium ion-capping and light illuminating strategy. With the aid of the light illuminating, the final 0D@2D product exhibits a superior practical H2O2 production rate of up to 1109 mmol·gcatalyst−1·h−1 with a high level of onset potential 0.78V and 94% H2O2 selectivity in H-cell. This improved performance arises from the introduction of UOCGSs and excellent charge transfer on the 0D@2D interface. Obviously, this work exhibits a new green stagey for the design of 0D@2D carbon-based structure via light illuminating.

Multifunctional ceramifiable silicone foam for smart fire fighting

The development of multifunctional silicone foam with high fire safety is of great significance to realize intelligent fire protection but challenging. Herein, a multifunctional ceramifiable fire-retardant silicone foam (MCSF) was fabricated by Ti3C2Tx nanosheet (MXene), multiwalled carbon nanotube (MWCNT), γ-aminopropyltriethoxysilane (APTES), Karstedt catalyst (Pt) and vinyl dimethylsiloxane via water–oil interface induced self-assembly and dehydrogenation foaming at room temperature. MCSF possessed low density and good mechanical properties. Its improved thermoelectric performance and sensitive fire-warning capability of MCSF were attributed to the skeleton supporting effect and unique electron transport effect between MWCNT and MXene. When being burned, MCSF was able to trigger the fire-warning system within 2.4 s and repeatedly alarm the fire reignition. Furthermore, owing to the synergism between APTES and Pt, MCSF exhibited good ceramization performance. When encountered high temperature, the MCSF surface rapidly ceramized, generating a ceramic-like barrier layer to block the further flame ablation, and it quickly self-extinguished after removing from flame. Besides, MCSF showed impressive thermal insulation and durable piezoresistive sensing. This work provides a new strategy for the preparation and application of multifunctional fireproof polymer foams.

An investigation on the impact of temperature variation over the performance of formamidinium tin iodide perovskite solar cell using SCAPS simulation

The primary goals of this project are to analyze the structure and assess the photovoltaic performance of n-i-p structured formamidinium tin iodide (FASnI3) perovskite solar cells at different operating temperatures to inspect the impact of operating temperature on device performance using a Solar Cell Capacitance Simulator (SCAPS). The simulated device structure is Au/spiro-OMeTAD/P3HT/FASnI3/PCBM/TiO2/FTO, whereas spiro-OMeTAD and TiO2 serve as the hole transport layer and electron transport layer, respectively. SCAPS simulation has been performed at 200, 300, 400, 500, and 600 K operating temperatures, and corresponding current density vs voltage (J–V) characteristics have been studied in addition to the photovoltaic metrics, such as open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), and power conversion efficiency (PCE). The thickness fluctuation and doping concentration variation of the absorber layer and the electron affinity variation and thickness variation of the Hole Transport Layer (HTL) and Electron Transport Layer (ETL) under temperature variation were also examined analytically. It has been found that there is an inverse relationship between temperature and power conversion efficiency (PCE). The extended thickness of the absorber layer enhances the PCE and JSC. Temperature variations in the thickness of the ETL and HTL have a minimal effect on the PCE and JSC of the device. At standard room temperature (300 K operating temperature), the solar cell parameters are found to be a short-circuit current density (JSC) of 17.93 mA/cm2, open-circuit voltage (VOC) of 1.06 V, fill factor (FF) of 67.46% and power conversion efficiency (PCE) of 17.93%.

Performance optimization of ETL-free bifacial perovskite solar cells for flexible devices: A simulation study

The versatile applications of flexible perovskite solar cells (PSCs) have made them promising energy-harvesting devices in our daily lives. The electron transport layer (ETL)-free PSCs offer a flexible approach for harnessing energy while adding a bifacial approach that can further improve the device performance. In our study, we have optimized ETL-free bifacial PSCs via simulation by selecting the suitable front transparent electrode (FTE), hole transport layer (HTL), and rear transparent electrode (RTE). Our investigation reveals that a potential well-like structure, associated with a small conduction band offset (CBO) at the FTE/perovskite interface holds significant potential for enhancing the power conversion efficiency (PCE) of the device. The upward shift in the valance band of HTL promotes recombination and reduces the device performance. The bandgap and electron affinity of RTE highly influence the band alignment at HTL/RTE interface. The NiO/Ag/NiO (NAN) tri-layer RTE provides a better band alignment with HTL, and improves the charge transportation and, hence, the device performance. Moreover, the thickness of the interfacial defect layer at the FTE/perovskite and perovskite/HTL interfaces significantly impacts device performance. In optimizing the perovskite absorber layer, a perovskite bandgap of 1.4 eV shows maximum device performance. Our optimized device shows a remarkable PCE of >27% for both front and rear illumination.

Effects of substrate availability and mitochondrial disruption on oxidative metabolism and sperm motility in fertile dogs.

In several mammalian species, the measurement of mitochondrial oxygen consumption (MITOX) under different metabolic conditions has demonstrated a positive correlation with sperm motility and may be a sensitive indicator of mitochondrial health. In general, the maintenance of sperm motility and many key sperm functions and fertilizing events are heavily energy-dependent processes, and some species-specific substrate preferences exist. Although canine sperm have been known to undergo capacitation and maintain motility with supplementation of a wide range of energy substrates, the relationship between mitochondrial function, and the maintenance of oxidative metabolism and sperm motility remain unclear. The objective of this study was to explore the metabolic flexibility of canine sperm, and to investigate the relationship between mitochondrial function, and maintenance of motility under differing nutrient conditions. We explored substrate preferences and the bioenergetics underlying maintenance of canine sperm motility by monitoring mitochondrial oxidative function and sperm kinematics in the presence of mitochondrial effector drug treatments: FCCP, antimycin (ANTI), and oligomycin (OLIGO). We hypothesized that canine sperm possess the ability to use compensatory pathways and utilize diverse nutrient sources in the maintenance of motility. Oxygen consumption (change in pO2, oxygen partial pressure) and sperm kinematics (CASA) were measured concurrently (t0-t30) to assess the relationship between oxidative metabolism and maintenance of sperm motility in dogs. Four media were tested: containing glucose, lactate, and pyruvate (GLP), containing glucose (G), fructose (F), or lactate and pyruvate (LP). In the absence of pharmacological inhibition of the electron transport chain, energetic substrate had no effect on sperm kinematics in fertile dogs. Following mitochondrial disruption by ANTI and OLIGO, mitochondrial oxygen consumption was negatively correlated with several sperm motility parameters in GLP, G, F, and LP media. In every media, FCCP treatment quickly induced significantly higher oxygen consumption than in untreated sperm, and spare respiratory capacity, the maximal inducible oxidative metabolism, was high. With respiratory control ratios RCR >1 there was no indication of bioenergetic dysfunction in any media type, indicating that sperm mitochondria of fertile dogs have a high capacity for substrate oxidation and ATP turnover regardless of substrate. Our results suggest MITOX assessment is a valuable tool for assessing mitochondrial functionality, and that canine sperm employ flexible energy management systems which may be exploited to improve sperm handling and storage.

Expression levels of the selenium-uptake receptor LRP8, the antioxidant selenoprotein GPX1 and steroidogenic enzymes correlate in granulosa cells.

Reactive oxygen species (ROS) are a by-product of the activity of cytochrome P450 steroidogenic enzymes. Antioxidant enzymes protect against ROS damage. To identify if any particular antioxidant enzyme is used to protect against ROS produced by granulosa cells as follicles enlarge and produce oestradiol, we measured in the bovine granulosa cells the expression of two steroidogenic enzymes (CYP11A1, CYP19A1), important for progesterone and oestradiol production. We also measured expression of the members (FDXR, FDX, POR) of their electron transport chains (ETC). We measured antioxidant enzymes (GPXs 1-8, CAT, SODs 1 and 2, PRDXs 1-6, GSR, TXN, TXNRDs 1-3). Since selenium is an active component of GPXs, the selenium-uptake receptors (LRPs 2 and 8) were measured. Only the selenium-dependent GPX1 showed the same increase in expression as the steroidogenic enzymes did with increasing follicle size. GPX4 and PRDX2/6 decreased with follicle size, whereas SOD1/2, CAT, GSR, and TXNRD3 were lowest at the intermediate sizes. The other antioxidant enzymes were unchanged or expressed at low levels. The expression of the selenium-uptake receptor LRP8 also increased significantly with follicle size. Correlation analysis revealed statistically significant and strongly positive correlations of the steroidogenic enzymes and their ETCs with both GPX1 and LRP8. These results demonstrate a relationship between expression of genes involved in steroidogenesis and selenium-containing antioxidant defence mechanisms. They suggest that during the late stages of folliculogenesis, granulosa cells are dependent on sufficient expression of GPX1 and the selenium transporter LRP8 to counteract increasing ROS levels caused by the production of steroid hormones.

Exploring Potential of Lead-Free KSn0.5Ge0.5I3 Based Perovskite Solar Cell: A Combined First-Principle DFT and SCAPS-1D Study

Perovskite solar cells present a promising alternative to conventional silicon or lead-based solar cells, offering a synergistic blend of cost-effectiveness and potential for elevated power conversion efficiency. We investigated the potential of an innovative KSn0.5Ge0.5I3-based perovskite solar cell (PSC) using density functional theory (DFT) and SCAPS-1D simulation studies. Computational analysis via DFT probed the crystal structure, elastic, mechanical, and optoelectronic properties of KSn0.5Ge0.5I3. Tolerance factor computation (0.94) and negative formation energy (-3.16eV) affirmed the thermodynamic stability of the orthorhombic phase in KSn0.5Ge0.5I3. Optical variables including refractive index, absorption coefficient, dielectric function, optical loss, and reflectivity, were computed to explore KSn0.5Ge0.5I3 viability in PV applications. Band structure analysis, density of states (DOS), and projected density of states (PDOS) have been used to determine the band gap (~1.87eV), effective masses, and mobility of e-/h+. We have conducted SCAPS-1D simulation for diverse PSCs configurations using various holes transport layers (HTLs) and electron transport layers (ETLs), identified IGZO (Eg = 3.05eV) as a proficient ETL while CuSbS2 (Eg = 1.58eV) as an effective HTL. A comprehensive investigation of parameters such as absorber layer thickness, shunt and series resistance, donor and acceptor density, absorber defect density, back contact metal, temperature, and interface characteristics was undertaken, and the impact on PV device performances was assessed through current-voltage (IV) and quantum efficiency (Q.E) characteristics curves. These findings underscore the potential of KSn0.5Ge0.5I3 as a promising material for PSCs, offering a sustainable and eco-friendly avenue for future renewable energy.

Temperature effects on Cadmium Selenide semiconductor-sensitized solar cells with SnO2 deposition as electron transport layer

Temperature effects on Cadmium Selenide semiconductor-sensitized solar cells with SnO2 deposition as electron transport layer

Observation of strong in-plane perpendicular electric field in a radio frequency plasma with a time-varying magnetic nozzle

The spatiotemporal evolution of the electron temperature and plasma potential in a 200-W radio frequency argon discharge with a time-varying (approximately 60 kHz) magnetic nozzle was measured. Unlike in conventional static magnetic nozzles, the two-dimensional profiles of the electron temperature and plasma potential changed in sync with the applied azimuthal electric field, not with the magnetic field. The temporally resolved electric field vectors demonstrated an enhancement of the perpendicular component, where the direction fairly matched that of electron Eθ×B drift, indicating a space charge separation. This observation suggests that the applied time-varying field actively enhanced cross field electron transport, resulting in a unique potential structure and charged particle acceleration.

Performance optimization of lead-free potassium germanium halide based perovskite solar cells: A numerical study

Conventional lead-halide perovskite solar cells (PSCs) have great potential as top contenders for commercial utilization due to their impressive performance. Nevertheless, the stability issues and undue toxicity have limited their widespread use. Consequently, lead-free germanium-based PSCs have materialized as potential substitutes due to their high working efficiency and exceptional sustainability. The current study has examined various configurations of non-toxic inorganic potassium germanium trichloride (KGeCl3) based PSC structure by using different Hole Transport Layers (HTL) and Electron Transport Layers (ETLs) respectively. This work proposes an efficient Ge-based PSC (structure; FTO/MoO3/KGeCl3/WS2/Au), which has been optimized theoretically using SCAPS-1D. The influence of the material parameters, such as the thickness of the absorber layer (nm), donor density (Nd), acceptor density (Na), absorber defect density(Nt), interface layer defect density (IL1& IL2), series resistance (Rs) and shunt resistance (Rsh), and working temperature (K), has been optimized. The open circuit voltage (Voc), current density (Jsc), fill factor (FF), and power conversion efficiency (PCE) of KGeCl3-based PSC have all been commendably optimized. The results indicated WS2 as the most effective ETL for KGeCl3 with MoO3 as an HTL, yielding notable cell performance with Voc of 0.88 V, Jsc of 41.45 mA/cm2, FF of 81.76 %, and PCE of 29.83 %. The outcomes of this simulation study suggest the utilization of KGeCl3 as the absorber layer, in conjunction with WS2 and MoO3 as advanced ETL and HTL layers, which pays the way for continued development and optimization of Ge-based PSCs for potential applications.

The genomic mosaic of mitochondrial dysfunction: Decoding nuclear and mitochondrial epigenetic contributions to maternally inherited diabetes and deafness pathogenesis

AimsMaternally inherited diabetes and deafness (MIDD) is a complex disorder characterized by multiorgan clinical manifestations, including diabetes, hearing loss, and ophthalmic complications. This pilot study aimed to elucidate the intricate interplay between nuclear and mitochondrial genetics, epigenetic modifications, and their potential implications in the pathogenesis of MIDD. Main methodsA comprehensive genomic approach was employed to analyze a Sicilian family affected by clinically characterized MIDD, negative to the only known causative m.3243 A > G variant, integrating whole-exome sequencing and whole-genome bisulfite sequencing of both nuclear and mitochondrial analyses. Key findingsRare and deleterious variants were identified across multiple nuclear genes involved in retinal homeostasis, mitochondrial function, and epigenetic regulation, while complementary mitochondrial DNA analysis revealed a rich tapestry of genetic diversity across genes encoding components of the electron transport chain and ATP synthesis machinery. Epigenetic analyses uncovered significant differentially methylated regions across the genome and within the mitochondrial genome, suggesting a nuanced landscape of epigenetic modulation. SignificanceThe integration of genetic and epigenetic data highlighted the potential crosstalk between nuclear and mitochondrial regulation, with specific mtDNA variants influencing methylation patterns and potentially impacting the expression and regulation of mitochondrial genes. This pilot study provides valuable insights into the complex molecular mechanisms underlying MIDD, emphasizing the interplay between nucleus and mitochondrion, tracing the way for future research into targeted therapeutic interventions and personalized approaches for disease management.

Electrochemical performance of g-C3N4 embedded NiO nanocomposite anodes for Lithium-ion batteries

The combination of two-dimensional layered heterostructures with transition metal oxide electrodes has attracted considerable attention. In this work, the hydrothermal method is adopted to produce graphitic carbon nitride-embedded Nickel oxide (g-CN/NiO) nanocomposites and tested their electrochemical performance against Li/Li+ half cells. The formation of g-CN/NiO nanocomposite is confirmed through structural analysis techniques, such as XRD and XPS. The scanning electron microscopy image reveals the existence of spherical g-CN/NiO nanocomposite. The g-CN embedded NiO anodes exhibited excellent electrochemical performance and cyclability, and the g-CN/NiO versus Li/Li+ half-cell delivered an initial discharge capacity of 906.4 mAh g-1 at a 0.1C rate. At 500 cycles, the anode delivered 195 mAh g-1 capacity with a columbic efficiency of 99.5 %. Interestingly, the g-CN/NiO anode exhibits two distinct trends in its cycling performance. Until 300 cycles, the capacity fade was perceived, and after 300 cycles, due to the overhang mechanism, an increasing trend was observed. The electrochemical result reveals that the introduction of g-CN improves the structural stability and electron transport properties of g-CN/NiO anodes.

Unlocking partial nitrification by acidophilic microorganisms in ultra-low strength wastewater: Long-term investigation and genomic insights

Achieving partial nitrification (PN) in low-strength wastewater is still a worldwide issue. In this study, conversion from nitrification to PN was successfully achieved with a self-sustained pH as low as 5.3 and a nitrite accumulation ratio (NAR) of 93.4 % by enriching novel acidic-tolerant functional flora. A strong positive correlation was observed between decreasing pH and NAR (R2 = 0.97). Even with 73.1 % reduction in influent ammonia (from 86.7 to 23.3 mg/L), high dissolved oxygen loading (4.5–5.3 mg/L), and extreme over-aeration, PN efficacy remained robust with the NAR consistently maintained at 90.6 ± 5.3 %. Over 180 days of continuous monitoring, novel ammonia-oxidizing bacteria (AOB) Candidatus Nitrosoglobus became the dominant nitrifying guild (1.65 %) with a specific growth rate of 0.091/day; however, traditional nitrifying bacteria exhibited impaired functionality and bacterial diversity was dramatically reduced. Amo abundance increased by 147 %, while Nxr in nitrifying bacteria dropped below detection limit, preventing complete nitrification. Upregulated electron transport chain genes enhanced electron flow, managing excess oxygen and effectively limiting harmful oxygen radical production, resulting in a desirable nitritation rate of 0.3 kg/m3·d with influent NH4+-N as low as 23.3 mg/L. These regulatory mechanisms boosted NH4+ oxidation efficiency, successfully unlocking scientific barriers associated with PN in ultralow-strength wastewater and laying the groundwork for future PN/A implementation.

The Role of Optimal Electron Transfer Layers for Highly Efficient Perovskite Solar Cells—A Systematic Review

Perovskite solar cells (PSCs), which are constructed using organic–inorganic combination resources, represent an upcoming technology that offers a competitor to silicon-based solar cells. Electron transport materials (ETMs), which are essential to PSCs, are attracting a lot of interest. In this section, we begin by discussing the development of the PSC framework, which would form the foundation for the requirements of the ETM. Because of their exceptional electronic characteristics and low manufacturing costs, perovskite solar cells (PSCs) have emerged as a promising proposal for future generations of thin-film solar energy. However, PSCs with a compact layer (CL) exhibit subpar long-term reliability and efficacy. The quality of the substrate beneath a layer of perovskite has a major impact on how quickly it grows. Therefore, there has been interest in substrate modification using electron transfer layers to create very stable and efficient PSCs. This paper examines the systemic alteration of electron transport layers (ETLs) based on electron transfer layers that are employed in PSCs. Also covered are the functions of ETLs in the creation of reliable and efficient PSCs. Achieving larger-sized particles, greater crystallization, and a more homogenous morphology within perovskite films, all of which are correlated with a more stable PSC performance, will be guided by this review when they are developed further. To increase PSCs’ sustainability and enable them to produce clean energy at levels previously unheard of, the difficulties and potential paths for future research with compact ETLs are also discussed.