Low Recombination Research Articles

Crafting in situ boron and selenium-doped carbon nitride nanosheets for turbocharged benzaldehyde to benzyl alcohol under solar spectrum

This research focuses on the fabrication and application of in situ boron and selenium-doped carbon nitride nanosheets as effective photocatalysts using sun spectrum irradiation to convert turbocharged benzaldehyde to benzyl alcohol. To optimize the doping method for enhanced activity, the effect of changing dopant concentrations on catalytic efficiency was thoroughly investigated. Furthermore, a through analysis of the reactive species involved in the conversion process helped to clarify the photocatalytic process. Based on charge transfer and low recombination, the results indicate that boron and selenium dopants work synergistically to improve catalytic efficiency. This research helps to improve the development of new photocatalytic materials for the sustainable and ecologically friendly transformation of organic molecules under solar spectrum irradiation. The regeneration of NADH using B,Se-CN photocatalyst demonstrates very good efficiency. It also demonstrated the high conversion efficiency of benzaldehyde to benzyl alcohol. This study emphasizes the possible use of B,Se-CN composite in the area of photoinduced conversion-based organic transformation. The knowledge gathered from this research opens up new avenues for the development and enhancement of effective photocatalysts that might be used in a range of solar-powered organic transformation processes.

Organic-inorganic hybrids of BiI3-polymers with embedded conductive carbon fillers displaying high SNR for direct X-ray imaging detectors

Organic polymers are light weight, low toxic and environmentally stable candidates of interest in X-ray detection application. But low attenuation and high recombination rate of charge carriers cause low sensitivity is major limitation of these detectors. In this work, organic polymers (PS/PMMA) composites were prepared with high-Z inorganic BiI3 by simple dry mixing technique. The organic-inorganic hybrid further embedded with conductive carbon filler (MWCNT, CB, GP) to improve the charge collection of the samples. Resistivity and mobility of the samples were studied with help of Hall measurements and mobility-lifetime was calculated by Hecth equation and found (2.1 ± 0.2) × 10−3 cm2V−1. The elemental analysis of the samples had been done by XPS analysis. The X-ray investigations done by using dental X-ray source and the sensitivity of the samples increases from 3.4 to 200 μGy−1 cm−3 by incorporating CB filler with a low leakage current of order of 33.3 pA/cm2.

Clustering of HR + /HER2− breast cancer in an Asian cohort is driven by immune phenotypes

Breast cancer exhibits significant heterogeneity, manifesting in various subtypes that are critical in guiding treatment decisions. This study aimed to investigate the existence of distinct subtypes of breast cancer within the Asian population, by analysing the transcriptomic profiles of 934 breast cancer patients from a Malaysian cohort. Our findings reveal that the HR + /HER2− breast cancer samples display a distinct clustering pattern based on immune phenotypes, rather than conforming to the conventional luminal A-luminal B paradigm previously reported in breast cancers from women of European descent. This suggests that the activation of the immune system may play a more important role in Asian HR + /HER2− breast cancer than has been previously recognized. Analysis of somatic mutations by whole exome sequencing showed that counter-intuitively, the cluster of HR + /HER2− samples exhibiting higher immune scores was associated with lower tumour mutational burden, lower homologous recombination deficiency scores, and fewer copy number aberrations, implicating the involvement of non-canonical tumour immune pathways. Further investigations are warranted to determine the underlying mechanisms of these pathways, with the potential to develop innovative immunotherapeutic approaches tailored to this specific patient population.

Facile fabrication of Ag decorated MnFeO3 catalyst: Comparative analysis of visible light driven antibiotic reduction and antibacterial performance

Photocatalysis is an effective method with the potential to eliminate pharmaceutical compounds from water sources. Manganese ferrite (MnFeO3), a type of multiferroic perovskite catalyst, has attracted significant attention due to its small band gap, however its application was limited due to its high recombination rate and low quantum efficiency. It was therefore aimed to improve the properties of MnFeO3 by doping silver (Ag)-particles. In this study, Ag–MnFeO3 photocatalysts with different Ag content (1–3 mmol%) were synthesized by performing a facile hydrothermal method. The as-prepared samples were characterized using x-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), ultraviolet–visible spectroscopy (DRS), photoluminescence spectroscopy (PL), electrochemical impedance spectroscopy (EIS) and Brunauer-Emmett-Teller (BET) method, showing successful addition of Ag-particles with the MnFeO3 structure. Then, the as-synthesized materials were investigated as: (i) photocatalysts for degradation tetracycline (TC) antibiotic and (ii) antibacterial agents for bacteria. The Ag–MnFeO3 catalyst demonstrated superior catalytic performance (95.7%), which was 1.6 times higher than that of pristine MnFeO3 (59.7%). The positive effect was ascribed to oxygen vacancies, enhanced light absorption ability, and lower recombination rate. The Ag–MnFeO3 catalyst also showed satisfactory removal performances in real water matrices. Furthermore, radical trapping tests depicted that the superoxide radicals played a dominant role in the photodegradation system. In addition, Box–Behnken design (BBD) was performed to determine the optimum conditions, which were determined as catalyst dosage of 0.45 g/L, initial TC concentration of 5.10 mg/L, and initial solution pH value of 3.69. In terms of antibacterial tests, the incorporation of Ag into the MnFeO3 structure greatly increased the antimicrobial resistance against bacteria. Our findings disclose that the incorporation of Ag into the MnFeO3 structure can be regarded as a feasible and promising approach to improve both photocatalytic degradation and antibacterial performances.

Calotropis-mediated biosynthesis of TiO2@SnO2/Ag nanocomposites for efficient perovskite photovoltaics

In this study, green SnO2@TiO2 nanocomposites were initially synthesized using an extract from the Calotropis plant as an electron transfer material for fabricating perovskite solar cells (PSCs). Further, plasmon impregnation (Ag-NPs) into the SnO2@TiO2 nanocomposites yielded nanocomposite (TiO2@SnO2/Ag) films. The effect of doping silver into the SnO2@TiO2 nanocomposites was investigated in detail to gain insights into how it influences the photovoltaic performance of the PSC. It resulted in enhanced quenching of photoluminescence compared to TiO2 and TiO2@SnO2 electron transport layers (ETLs), indicating faster charge extraction. PSCs utilizing the TiO2@SnO2/Ag ETL showed significantly improved performance with a power conversion efficiency of 22.2 %, a higher fill factor, and reduced hysteresis compared to cells with TiO2 and TiO2@SnO2 ETLs. The characterization of the nanocomposites revealed that the TiO2@SnO2/Ag ETL led to perovskite films with improved crystallinity, morphology, charge separation, and transfer properties. Electrochemical impedance spectroscopy confirmed the TiO2@SnO2/Ag ETL facilitated faster charge transfer and lower recombination at interfaces. Finally, the TiO2@SnO2/Ag ETL-based devices exhibited superior long-term stability in air, maintaining over 87 % of their initial efficiency. This work demonstrates that the incorporation of TiO2@SnO2/Ag nanocomposites is effective for developing high-performance and stable PSCs.

Performance analysis of p-MoTe2/n-MoSe2 -based bifacial solar cells with p+-N:Cu2O as BSF layer by SCAPS-1D

Photovoltaic solar cells (PVSC) with Molybdenum telluride (MoTe2) have received considerable attention because of their wide range of absorption, along with the absence of dangling bonds at their surface. Here, MoTe2-based PVSC with a preliminary device structure of Al/ITO/n-MoSe2/p-MoTe2/Pt was designed and estimated its performance by using the solar cell capacitance simulator in one dimension software program (SCAPS-1D). The effect of different parameters like thickness, doping density, and interface defect density of each layer was also investigated. Our investigation reveals that a moderate thickness of ∼1000 nm of MoTe2 and 500 nm of MoSe2, a higher concentration of more than 1017 cm−3 for both layers and moderate defect density of below 1014 cm−3 are favorable for the better PVSC device. The effect of integrating of p + -N:Cu 2 O layer in the MoTe2-based PVSC as a back surface field (BSF) layer was also taken into account to improve the device performance. We also evaluated the output parameters of the optimized Al/ITO /n-MoSe 2 /p-MoTe 2 /p + -N:Cu 2 O/Pt PVSC with different series and shunt resistance, back-metal work function, and working temperature. Our analysis shows that minimum series resistance, higher shunt resistance, lower working temperature, and a high back-metal work function of more than 5.35 eV are advantageous for superior PVSC due to low recombination losses, low electrical losses, and better transport of charge carriers. The best performance of 28.75% with Jsc of 34.11 mA cm−2, Voc of 0.98 V, and FF of 86.3%, was achieved by optimizing all parameters. To further improve the device performance, the bifacial mode of optimized Al/ITO /n-MoSe 2 /p-MoTe 2 /p + -N:Cu 2 O/Pt was considered and the PV performance of the proposed bifacial-PVSC has been also studied by using SCAPS-1D. Compared to the mono-facial device, a bifacial-PVSC device shows better performance with the bifacial factor of 77.5%, bifacial gain of 14.78%, and a higher PCE of 32.17%.

Study of the optoelectronic properties and the doping effect on different atoms of the CsSnBr3 supercell to absorb visible light: First-principles calculations

Lead-free halide perovskites are prototype materials-based solar cells and many other devices optoelectronic, that have exhibited high power conversion efficiencies, high absorption, and the most important thing is environmentally friendly. This paper presents detailed ab initio calculations of the structural, electronic and optical properties of inorganic perovskite CsSnBr3 by using the density functional theory (DFT) and the time-dependent density functional theory (TDDFT). The main objective of this work is to investigate the effects of Mn doped on the optoelectronic properties of CsSnBr3 supercell such as we have substituted the Cs atoms (Cs1−xMnxSnBr3) and Sn atoms (CsSn1−xMnxBr3) respectively by Mn transition metal atoms. The results show that the incorporation of Mn metal in the studied compound improves significantly the optoelectronic properties such that the band gap of CsSnBr3 is 0.546 eV becomes 0.208 eV after doping. The case of the doped samples are the more suitable choice for optoelectronic devices due to the high dielectric constant and a small gap energy, which shows a low recombination rate, and consequently, improves the device performance especially in the visible energy range (1.65–3.26 eV).

Improved performance of inorganic CsPbI3 perovskite solar cells with WO3/C60 UTL bilayer as an ETL structure: a computational study

CsPbI3, also known as cesium lead iodide, has garnered significant attention as a potential absorber in perovskite solar cells (PSCs). CsPbI3-PSCs have not matched the high performance of hybrid PSCs. This study aimed to identify an effective combination of charge transport layers. Six-hole transporting layers (HTLs) including Spiro-OMeTAD, Cu2O, CuO, CuAlO2, CuSbS2, and SrCu2O2, as well as five electron transporting layers (ETLs) such as TiO2, WO3, ZnO, IGZO, and CdZnS, were tested separately in 30 PSCs. The findings of this research indicate that CuAlO2 as the HTL and WO3 as the ETL that are the most appropriate materials among the options examined, so we use FTO/WO3/CsPbI3/CuAlO2/Au as a required PSC. In this research, we used SCAPS (Solar Cell Capacitance Simulator)−1D device modeling to investigate the bilayer ETL of inorganic CsPbI3-PSC and discover the methods to improve their efficiency. In planar PSCs, optimizing electron–hole pair extraction and recombination at the ETL/perovskite interface is crucial for achieving high performance. The key concept is to enhance the WO3/perovskite interface properties by adding a 5 nm ultra-thin layer (UTL) of C60. The bilayer structure WO3/C60 was found to have the advantage of high electron extraction and low interfacial recombination, primarily due to more effective energy level alignment and defect passivation. To achieve the superior efficiency of PSC, various factors such as defect and doping densities in all layers, the energy level alteration of ETL and HTL, interface defect densities on both ETL and HTL sides, back metal contact, operating temperature, and parasitic resistances were optimized. After optimizing these parameters, the efficiency of the system containing WO3/C60 bilayer ETL was found to be 29.39%. The current work proposes a straightforward and promising method to create photovoltaic devices, especially for many types of perovskites, with desirable charge transport layers and recombination properties.

Facilely Modified Nickel-Based Hole Transporting Layers for Organic Solar Cells with 19.12% Efficiency and Enhanced Stability.

Hole transporting layers (HTLs), strategically positioned between electrode and light absorber, play a pivotal role in shaping charge extraction and transport in organic solar cells (OSCs). However, the commonly used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, with its hygroscopic and acidic nature, undermines the operational durability of OSC devices. Herein, an environmentally friendly approach is developed utilizing nickel acetate tetrahydrate (NiAc·4H2O) and [2-(9H-carbazol-9-yl)ethyl] phosphonic acid (2PACz) as the NiAc·4H2O/2PACz HTL, aiming at overcoming the limitations posed by the conventional PEDOT:PSS one. Encouragingly, a remarkable power conversion efficiency (PCE) of 19.12% is obtained for the OSCs employing NiAc·4H2O/2PACz as the HTL, surpassing that of devices with the PEDOT:PSS HTL (17.59%), which is ranked among the highest ones of OSCs. This improvement is attributed to the appropriate work function, enhanced hole mobility, facilitated exciton dissociation efficiency, and lower recombination loss of NiAc·4H2O/2PACz-based devices. Furthermore, the NiAc·4H2O/2PACz-based OSCs exhibit superior operational stability compared to their PEDOT:PSS-based counterparts. Of significant note, the NiAc·4H2O/2PACz HTL demonstrates a broad generality, boosting the PCE of the PM6:PY-IT and PM6:Y6-based OSCs from 16.47% and 16.79% (with PEDOT:PSS-based analogs as HTLs) to 17.36% and 17.57%, respectively. These findings underscore the substantial potential of the NiAc·4H2O/2PACz HTL in advancing OSCs, offering improved performance and stability, thereby opening avenue for highly efficient and reliable solar energy harvesting technologies.

Phased assembly of neo-sex chromosomes reveals extensive Y degeneration and rapid genome evolution in Rumex hastatulus.

Y chromosomes are thought to undergo progressive degeneration due to stepwise loss of recombination and subsequent reduction in selection efficiency. However, the timescales and evolutionary forces driving degeneration remain unclear. To investigate the evolution of sex chromosomes on multiple timescales, we generated a high-quality phased genome assembly of the massive older (<10MYA) and neo (<200,000 years) sex chromosomes in the XYY cytotype of the dioecious plant Rumex hastatulus and a hermaphroditic outgroup R. salicifolius. Our assemblies, supported by fluorescence in situ hybridization, confirmed that the neo-sex chromosomes were formed by two key events: an X-autosome fusion and a reciprocal translocation between the homologous autosome and the Y chromosome. The enormous sex-linked regions of the X (296 MB) and two Y chromosomes (503 MB) both evolved from large repeat-rich genomic regions with low recombination; however, the complete loss of recombination on the Y still led to over 30% gene loss and major rearrangements. In the older sex-linked region, there has been a significant increase in transposable element abundance, even into and near genes. In the neo sex-linked regions, we observed evidence of extensive rearrangements without gene degeneration and loss. Overall, we inferred significant degeneration during the first 10 million years of Y chromosome evolution but not on very short timescales. Our results indicate that even when sex chromosomes emerge from repetitive regions of already-low recombination, the complete loss of recombination on the Y chromosome still leads to a substantial increase in repetitive element content and gene degeneration.

Efficient hierarchical ZIF-based electro/photocatalyst toward hydrogen generation and evolution

In this study, a well-designed hierarchical BiFeO3/ZIF-67 (BFO-ZIF) composite was successfully synthesized to improve the performance of photocatalytic hydrogen generation in comparison to bare BiFeO3 and ZIF-67. Moreover, the behavior of the resultant electrocatalysts was also investigated in the hydrogen evolution reaction (HER). The synthesized electro-photocatalysts were characterized by various physical and photo/electrochemical analyses. The remarkable outcomes of the composite with 50 wt% of ZIF-67 in hydrogen generation correspond to the high specific surface area of the photocatalyst concurrently with the formation of active sites and new charge channels, leading to a modified charge transfer pathway and lower electron-hole recombination. The maximum H2 generation rate over the optimal BFO-ZIF composite (BFO-ZIF(50)) attained 1617 μmol g−1 h−1 during visible light exposure, surpassing the rates observed for pure BFO and ZIF-67. Furthermore, the BFO-ZIF(50) electrocatalyst, with the onset potential of −0.089 V, resulted in an overpotential of −0.19 V at a current density of 10 mA cm−2, while a Tafel slope of 81.6 mV dec−1 in 1.0 M KOH showed the highest activity. The elevated photocatalytic hydrogen generation and improved HER performance of the developed catalysts signify a synergistic effect resulting from the junction and the Z-scheme charge transfer mechanism between the ZIF-67 and BFO nanomaterials. This introduces the BFO-ZIF composite as an efficient photocatalyst and electrocatalyst for hydrogen generation and evolution reaction.

The Role of Device Architecture and Interfacial Layer on Performance of Semitransparent Organic Solar Cells

Semitransparent organic solar cells (ST‐OSCs) generally suffer from voltage loss in comparison to their opaque counterparts. Herein, ST‐OSCs constructed with conventional and inverted structures have been explored. The voltage losses of the inverted ST‐OSCs are lower than that of the conventional architectures when the thicknesses of the top transparent electrodes approach the percolation threshold, which is attributed to the larger surface energy of the bottom seeding layers, higher built‐in electric fields, and lower recombination losses. Moreover, ST‐OSCs with conventional architectures based on four commonly used electrode transporting layers (ETLs) PDINN, PDINO, PNDIT‐F3N, and PFN‐Br are employed to distinguish the Voc variation when capping with 10 nm top electrodes. It is revealed that ETL with larger surface energy and a stronger ability to reduce the cathode work function is more beneficial for reducing the voltage loss for ST‐OSCs. This work demonstrates the crucial role of device structure and interfacial layers in optimizing the ST‐OSC device performance.

Defective transfer of parental histone decreases frequency of homologous recombination by increasing free histone pools in budding yeast.

Recycling of parental histones is an important step in epigenetic inheritance. During DNA replication, DNA polymerase epsilon subunit DPB3/DPB4 and DNA replication helicase subunit MCM2 are involved in the transfer of parental histones to the leading and lagging strands, respectively. Single Dpb3 deletion (dpb3Δ) or Mcm2 mutation (mcm2-3A), which each disrupts one parental histone transfer pathway, leads to the other's predominance. However, the biological impact of the two histone transfer pathways on chromatin structure and DNA repair remains elusive. In this study, we used budding yeast Saccharomyces cerevisiae to determine the genetic and epigenetic outcomes from disruption of parental histone H3-H4 tetramer transfer. We found that a dpb3Δ mcm2-3A double mutant did not exhibit the asymmetric parental histone patterns caused by a single dpb3Δ or mcm2-3A mutation, suggesting that the processes by which parental histones are transferred to the leading and lagging strands are independent. Surprisingly, the frequency of homologous recombination was significantly lower in dpb3Δ, mcm2-3Aand dpb3Δ mcm2-3A mutants, likely due to the elevated levels of free histones detected in the mutant cells. Together, these findings indicate that proper transfer of parental histones during DNA replication is essential for maintaining chromatin structure and that lower homologous recombination activity due to parental histone transfer defects is detrimental to cells.

NiFe2O4/CuO heterostructures optical, magnetic and photocatalytic properties: Methylene blue dye degradation under solar light irradiation

A series of NiFe2O4/CuO heterostructures were prepared and their photocatalytic potential was compared with bare NiFe2O4 (NFO) and CuO (CO). The prepared materials were subjected to characterization using a combination of X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy, and UV–visible (UV–Vis) spectroscopy techniques. Photocatalytic efficiency was studied for removing methylene blue (MB) dye under solar light irradiation. The NiFe2O4/CuO heterostructures demonstrated superior removal of MB dye versus other materials. The decline in PL intensity for heterostructure revealed a low recombination rate of charge carriers. Maximum dye removal over NiFe2O4/CuO heterostructure was achieved for 20 mg/L dye catalyst dose and 20 mg/L dye solution at pH 10. Scavenging studies showed that hydroxyl radicals and electrons played a major role in the degradation of dye. The removal efficiency was 80.01 %, which was reduced to 78.83 % for NiFe2O4/CuO heterostructures after four consecutive cycles, which indicates its high stability under solar light irradiation. The NiFe2O4/CuO heterostructures may find potential applications in water treatment for removing organic dyes under visible light owing to their robust catalytic performance under solar light irradiation.

Amine functionalized graphene oxide decorated with ZnO-WO3 nanocomposites for remediation of organic dye from wastewater

Photocatalytic degradation is as an efficient technique to eradicate toxic chemical pollutants from contaminated water sources. However, the selectivity and photocatalytic activity are the challenging targets to explore the new photocatalysts. Therefore, our research goal is to develop a suitable photocatalyst to satisfy the recent photocatalytic degradation demand. In this work, amine functionalized graphene oxide (NH2-GO) supported heterojunction ternary novel nanocomposites (NH2-GO/ZnO-WO3) were prepared via simple solvothermal method. Structural and morphological investigations of the prepared composites are systematically observed by Field Emission Scanning Electron Spectroscopy (FE-SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Ultraviolet–Visible (UV–vis) Spectroscopy. FT-IR analysis confirmed the effective functionalization of amine on graphene oxide. The XRD results indicated that the prepared nanocomposites were free from any impurities and the binary composite (NH2-GO/ZnO) showed hexagonal wurtzite structure, whereas the ternary composite (NH2-GO/ZnO-WO3) exhibited mix crystal structure of monoclinic and hexagonal phase of WO3 and ZnO, respectively. The synthesized ternary photocatalyst (NH2-GO/ZnO-WO3) demonstrated superior photocatalytic efficiency towards various organic dyes such as cationic dye methylene blue (MB, 85.89%) and anionic dye methyl orange (MO, 60.98%) compared to binary photocatalyst (NH2-GO/ZnO) that showed only 52.28% of MB and 25.8% of MO dye degradation under UV light irradiation. The enhanced photocatalytic performance was mainly due to the low recombination rate of photogenerated electron-hole pair, narrow band gap, and large surface area of ternary composite. The presence of lone pair electrons in amino group provides a negative-charged surface composite resulting good interaction with cationic dye is the key to upgrade the photocatalytic performance. The ternary nanocomposite NH2-GO/ZnO-WO3 has the capacity to be a competent and acceptable photocatalyst for the photodegradation of organic dyes used in industries.

Carbon-supported g-C3N4 photocatalyst for the treatment of vapor isobutanol as odorous VOC

Graphitic carbon nitride (g-C3N4) is a metal-free photocatalyst active under visible light but exhibits low photocatalytic activity due to its low specific surface area and fast recombination rates. However, it is possible to enhance its effectiveness and performance can be significantly improved by preparing composites of g-C3N4 with activated carbon (AC). In this manuscript, agave bagasse was employed as a precursor for activated carbon ranging from relatively low, medium and high porosity. The ability of the g-C3N4/activated carbon composite to degrade isobutanol as a model odorous VOC was evaluated under visible light. Different activation/deactivation phenomena were observed at different operation times. It was found that materials with higher porosity presented a higher level of degradation of the model VOC. However, synergy between the materials was demonstrated for the dynamic removal of isobutanol. These results demonstrate the synthesis of a composite with photocatalytic and adsorption properties based on g-C3N4 supported on activated carbon obtained from agave bagasse, which could contribute to the development of green photocatalytic materials and serve as an alternative for managing waste from the tequila industry.

Efficient Ternary Organic Solar Cells with Suppressed Nonradiative Recombination and Fine-Tuned Morphology via IT-4F as Guest Acceptor.

The large open circuit voltage (VOC) loss is currently one of the main obstacles to achieving efficient organic solar cells (OSCs). In this study, the ternary OSCs comprising PM6:BTP-eC9:IT-4F demonstrate a superior efficiency of 18.2 %. Notably, the utilization of the medium bandgap acceptor IT-4F as the third component results in an exceptionally low nonradiative recombination energy loss of 0.28 V. The desirable energy level cascade is formed among PM6, BTP-eC9, and IT-4F due to the low-lying HOMO and LUMO energy levels of IT-4F. More importantly, the VOC of PM6:BTP-eC9:IT-4F OSCs can reach as high as 0.86 V, which is higher than both binary OSCs without sacrificing JSC and FF. Besides, this strategy proved that IT-4F can not only broaden the absorption range but also work as a morphology modifier in PM6:BTP-eC9:IT-4F OSCs, and there also exists efficient energy transfer between BTP-eC9 and IT-4F. This result provides a promising way to suppress the nonradiative recombination energy loss and realize higher VOC than the two binary OSCs in ternary OSCs to obtain high power conversion efficiencies.

Achieving High Fill Factor in Organic Photovoltaic Cells by Tuning Molecular Electrostatic Potential Fluctuation.

In the field of organic photovoltaics (OPVs), significant progress has been made in tailoring molecular structures to enhance the open-circuit voltage and the short-circuit current density. However, there remains a crucial gap in the development of coordinated material design strategies focused on improving the fill factor (FF). Here, we introduce a molecular design strategy that incorporates electrostatic potential fluctuation to design organic photovoltaic materials. By reducing the fluctuation amplitude of IT-4F, we synthesized a new acceptor named ITOC6-4F. When using PBQx-TF as a donor, the ITOC6-4F-based cell shows a markedly low recombination rate constant of 0.66×10-14 cm3 s-1 and demonstrates an outstanding FF of 0.816, both of which are new records for binary OPV cells. Also, we find that a small fluctuation amplitude could decrease the energetic disorder of OPV cells, reducing energy loss. Finally, the ITOC6-4F-based cell creates the highest efficiency of 16.0 % among medium-gap OPV cells. Our work holds a vital implication for guiding the design of high-performance OPV materials.

Achieving High Fill Factor in Organic Photovoltaic Cells by Tuning Molecular Electrostatic Potential Fluctuation

AbstractIn the field of organic photovoltaics (OPVs), significant progress has been made in tailoring molecular structures to enhance the open‐circuit voltage and the short‐circuit current density. However, there remains a crucial gap in the development of coordinated material design strategies focused on improving the fill factor (FF). Here, we introduce a molecular design strategy that incorporates electrostatic potential fluctuation to design organic photovoltaic materials. By reducing the fluctuation amplitude of IT‐4F, we synthesized a new acceptor named ITOC6‐4F. When using PBQx‐TF as a donor, the ITOC6‐4F‐based cell shows a markedly low recombination rate constant of 0.66×10−14 cm3 s−1 and demonstrates an outstanding FF of 0.816, both of which are new records for binary OPV cells. Also, we find that a small fluctuation amplitude could decrease the energetic disorder of OPV cells, reducing energy loss. Finally, the ITOC6‐4F‐based cell creates the highest efficiency of 16.0 % among medium‐gap OPV cells. Our work holds a vital implication for guiding the design of high‐performance OPV materials.

Optimization of a Solution-Processed TiOx/(n)c-Si Electron-Selective Interface by Pre- and Postdeposition Treatments.

Developing a vacuum-free and low-temperature deposition technique for dopant-free carrier-selective materials without sacrificing their performance can reduce the fabrication cost and CO2 footprint of silicon heterojunction (SHJ) solar cells. In this contribution, to activate the full capacity of the solution-processed TiOx as an electron-selective passivation contact, the effects of various pre- and postdeposition treatments on the passivation quality and contact resistivity are investigated simultaneously. It is demonstrated that the electrical properties of a thin TiOx layer spin-coated on an n-type silicon substrate can be remarkably improved through tailor-made pre- and postdeposition treatments. A notable low surface recombination velocity (SRV) of 6.54 cm/s and a high implied open-circuit voltage (iVoc) of 706 mV are achieved. In addition, by inserting a 1 nm LiFx buffer layer between TiOx and Al metal contact, a low contact resistivity (ρc) of 15.4 mΩ·cm2 is extracted at the n-Si/SiOx/TiOx heterojunction. Our results bring the solution-processed TiOx electrical properties to a level on par with those of state-of-the-art pure TiOx layers deposited by other techniques. Chemical and electrical characterizations elucidate that the improved electrical properties of the investigated Si/SiOx/TiOx heterojunction are mediated by the concomitant involvement of chemical and field-effect passivation.