Lowest Unoccupied Molecular Orbital Energy Levels Research Articles

Insights into the structural, electronic, quantum chemical properties and molecular docking studies on novel NAMPT inhibitor molecule

This research paper presents a comprehensive study on a novel NAMPT (Nicotinamide phosphoribosyl transferase) inhibitor molecule, N- [4- [(4R)-1,4-dimethyl-6-oxidanylidene-4,5-dihydropyridazin-3-yl] phenyl]-5,7-dihydropyrrolo [3,4-b] pyridine-6-carboxamide], with the potential applications in cancer therapy. We performed quantum chemical calculations with DFT and topological investigations on the molecule to understand its electronic properties and chemical behaviour. The study covers basic molecular properties, molecular planarity and various electronic properties, including the HOMO (Highest Occupied Molecular Orbital), LUMO (Lowest Unoccupied Molecular Orbital) energy levels, the energy gap of 4.09 eV, ionization potential, electron affinity, electronegativity, chemical potential, chemical hardness, chemical softness, electrophilicity index, Mulliken atomic charges, Laplacian bond order, and ESP (Electrostatic Potential) properties. Moreover, we studied the nature of bonding and interactions within the molecule using ELF (Electron Localization Function), LOL (Localized Orbital Locator), RDG (Reduced Density Gradient), and NCI (Non-covalent Interaction). An analysis of the title molecule's molecular thermodynamic properties demonstrates its intrinsic stability under thermal and quantum effects. Molecular docking studies were also performed to reveal how the molecule interacts with its target protein, exhibiting a strong binding affinity for NAMPT target proteins (7PPF and 5WI0), which could help develop future cancer drugs. This multifaceted investigation provides a detailed understanding of the molecular structure and interactions of the molecule with NAMPT protein, potentially paving the way for its potential use as a cancer therapy.

Molecular understanding of electron donor influences in dye-sensitized solar cells of novel series-based D-A’-(π-A)2

The efficiency of the designed dye-sensitized solar cells (DSSCs) containing phenothiazine phenoxazine, and 5,10-dimethylphenazine as donors and triazine, phenyl with D-A’-(π-A)2 architecture has been examined utilizing Time-dependent (TD-DFT) and Density Functional Theory (DFT) techniques. The geometrical structures, electrical characteristics, absorption, and photovoltaic characteristics were studied using these techniques. Additionally, the computed findings show that various layouts can alter the HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital) energy levels and reduce the energy gap between 1.63 and 2.30 eV. The absorption undergoes a redshift displacement. These bands are between 300 and 400 nm. This work aims at calculating the structural geometries and the electronic and optical properties of the designed dyes. In order to shed light on the bridging influence on geometric and TD-BHandH/6-31G(d) for optoelectronic properties, the density functional theory (DFT) and time-dependent TD-DFT at the B3LYP/6-31G(d) level were examined. Additionally, the complex [email protected] cluster's binding energies have been investigated.

Data-Driven Insight into the Reductive Stability of Ion-Solvent Complexes in Lithium Battery Electrolytes.

Lithium (Li) metal batteries (LMBs) are regarded as one of the most promising energy storage systems due to their ultrahigh theoretical energy density. However, the high reactivity of the Li anodes leads to the decomposition of the electrolytes, presenting a huge impediment to the practical application of LMBs. The routine trial-and-error methods are inefficient in designing highly stable solvent molecules for the Li metal anode. Herein, a data-driven approach is proposed to probe the origin of the reductive stability of solvents and accelerate the molecular design for advanced electrolytes. A large database of potential solvent molecules is first constructed using a graph theory-based algorithm and then comprehensively investigated by both first-principles calculations and machine learning (ML) methods. The reductive stability of 99% of the electrolytes decreases under the dominance of ion-solvent complexes, according to the analysis of the lowest unoccupied molecular orbital (LUMO). The LUMO energy level is related to the binding energy, bond length, and orbital ratio factors. An interpretable ML method based on Shapley additive explanations identifies the dipole moment and molecular radius as the most critical descriptors affecting the reductive stability of coordinated solvents. This work not only affords fruitful data-driven insight into the ion-solvent chemistry but also unveils the critical molecular descriptors in regulating the solvent's reductive stability, which accelerates the rational design of advanced electrolyte molecules for next-generation Li batteries.

An effective strategy to design high-performance wide bandgap polymer donors for organic solar cells by increasing the backbone curvature

Although wide bandgap (WBG) polymer donors are widely used in non-fullerene organic solar cells (OSCs), only a few WBG polymers exhibited high power conversion efficiencies (PCEs). Developing WBG donors with ideal complementary absorption with narrow bandgap non-fullerene acceptors is critical to further improving the photovoltaic performance of OSCs. Here, we provide an effective strategy to widen the bandgap (Eg) of polymers by increasing the curvature of the polymer donor backbone structure and compare it with the fluorination strategy. Both experimental and theoretical results demonstrated that the fluorination strategy reduced the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of PBDT-DT2FBT with little effect on the Eg. In contrast, the polymer PBDT-DTfBT, with a large backbone curvature, exhibited a reduced HOMO energy level and a significantly increased LUMO energy level, resulting in a significant increase in the optical Eg of 0.19 eV. The PBDT-DTfBT-based device achieved a high PCE of 15.89%, which far exceeded the PCEs of the PBDT-DTBT (9.84%) and PBDT-DT2FBT-based devices (8.02%). This work could guide the design of high-performance WBG donors.

The tribo-piezoelectric microscopic coupling mechanism of ferroelectric polymers and the synchronous online monitoring of load distribution/roller speed for intelligent bearings

The tribo-piezoelectric microscopic coupling mechanism of ferroelectric polymers remains elusive due to the complicated interfacial electron transfer behavior and dipole-dipole interactions, limiting the development of high-performance tribo-piezoelectric hybrid nanogenerators. Herein, we take PVDF-Cu as an example to investigate the tribo-piezoelectric coupling mechanism at the ferroelectric polymer/metal interface under compression via first-principles calculations and KPFM experiments. It is revealed that the local deformation of the ferroelectric β-phase PVDF molecular chain not only concentrates the LUMO (lowest unoccupied molecular orbital) in the deformed region and lowers the LUMO energy level, but also changes the orientation and polarity of the dipoles, thus enhancing the triboelectric and piezoelectric charges. Furthermore, this work identifies dipole-dipole interactions and intramolecular/intermolecular electron transfer as the key intrinsic factors that promote the synergistic enhancement of triboelectricity and piezoelectricity. Specifically, the intramolecular and intermolecular electron transfer within the β-phase PVDF induced by the interfacial electron transfer enhances the dipole polarization, thus enhancing the piezoelectric effect, which in turn generates stronger dipole-dipole interactions to provide additional electrostatic potential energy for electrons in the polymer, finally enhancing the interfacial triboelectric effect again. On this basis, we propose the microscopic coupled electrification model at the ferroelectric polymer/metal interface and clarify that the triboelectric and piezoelectric effects dominate at low and high pressures, respectively. Inspired by the above microscopic mechanism, we regulate the ferroelectric β phase of PVDF film to develop a tribo-piezoelectric coupled pressure sensor(T-PPS) with high sensitivity(0.95 V/kPa) and wide measurement range(>10 MPa). In addition, benefiting from the excellent sensing characteristics of T-PPS, we propose a novel strategy based on pressure fluctuation detection of the bearing outer ring, enabling the high-precision synchronous online testing of load distribution and roller speed for intelligent bearings. This method can address the problems of existing measurements such as the destruction of bearings structure, interference with cage motion, and low integration.

Regulating energy gap in Ir-based ionic complexes to generate near-infrared emissions: Application in solid-state light-emitting electrochemical cells

Solid-state light-emitting electrochemical cells (LECs) exhibit high potential for commercial electronics owing to their simple solution-processable device architectures, low-voltage operation, and compatibility with inert metal electrodes. However, the low device efficiency of most deep-red and near-infrared (NIR) LECs hinders their application (external quantum efficiency (EQE) < 1.00%). In this study, we demonstrate a simple method to tune the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of iridium-based ionic transition metal complexes (iTMCs) to generate NIR emissions. We investigate a series of cationic iridium complexes with small energy gaps, with 2,2′-bibenzo[d]thiazole fixed as N^N ligand moiety mainly controlling the LUMO energy level, changing a series of C^N ligands. All complexes exhibited deep red/NIR phosphorescence, and these combined devices provided emission peaks at 690–730 nm and were applied as components in LECs, exhibiting a maximum EQE of 1.78% in electroluminescence devices. Using a host–guest emission system with the iridium complex YIr as the host and complex TBBI as the guest, the highest EQE of LECs could be further enhanced to>2.34%, which is the highest value reported for NIR LECs.

Development of novel acceptors with deep LUMO energy levels

Pure-organic red exciplex emitters are far from satisfactory in terms of quantity and efficiency. The narrow lowest unoccupied molecular orbital (LUMO) energy levels range of reported acceptors together with the intrinsic exciton non-radiative decay are the dominant factors restricting the progress of red exciplexes. Herein, two acceptor molecules operating at unique LUMO of -3.51 and -3.56 eV, namely 4-(6-([1, 1’: 3’, 1”-terphenyl]-5’-yl)-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl) benzonitrile (CNAI-tPh) and 4-(6-(4-(4, 6-diphenyl-1, 3, 5-triazin-2-yl)phenyl)-1, 3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl) benzonitrile (CNAI-TRz), were developed. Through binding to a donor whose HOMO energy level is -5.53 eV, the CNAI-TRz-related OLEDs attained a higher device efficiency amounting to 7.7% with a red-shifted spectrum compared to the CNAI-tPh-related devices. These results are remarkable among the reported pure-organic red exciplex-based OLEDs and demonstrate the tremendous potential of our synthesized acceptors in efficient red exciplexes.

Designed and synthesized de novo ANTPABA-PDI nanomaterial as an acceptor in inverted solar cell at ambient atmosphere

In this work, a novel soluble and air-stable electron acceptor containing perylenediimide moiety named ANTPABA-PDI was designed and synthesized with band gap 1.78eV and that was used as non-fullerene acceptor material. ANTPABA-PDI possess not only good solubility but also much lower LUMO (lowest unoccupied molecular orbital) energy level. Furthermore, its excellent electron acceptor capability also supported by density functional theory calculation which validates the experimental observations. Inverted organic solar cell has been fabricated using ANTPABA-PDI along with P3HT as standard donor material in ambient atmosphere. The device, after characterization in open air, exhibited a power conversion efficiency of 1.70%. This is the first ever PDI based organic solar cell that has been fabricated completely in ambient atmosphere. The characterizations of the device have also been performed in ambient atmosphere. This kind of stable organic material can easily be used in fabricating organic solar cell and therefore it can be used as the best alternative as non-fullerene acceptor materials.

Enhanced n‐Type Thermoelectric Performance of Conjugated Polymers Based on an Indandione‐Terminated Quinoidal Unit through Comonomer Optimization

Comprehensive SummaryConjugated polymers (CPs) containing quinoidal units are promising in n‐type organic thermoelectric materials because of their deep‐positioned lowest unoccupied molecular orbital (LUMO) energy levels and planar conjugated backbones. Herein, three CPs have been synthesized by copolymerizing an indandione‐terminated quinoidal unit with bithiophene derivatives. Owning to the high electron affinity of the indandione‐terminated quinoidal unit, all polymers showed deep LUMO energy levels below –4.10 eV. Incorporating electron‐withdrawing substituents (F or CN) on the bithiophene comonomer can further downshift the LUMO energy levels. As a result, a more efficient n‐doping process can be realized when employing 4‐(2,3‐dihydro‐1,3‐dimethyl‐1H‐benzimidazol‐2‐ yl)‐N,N‐dimethylbenzenamine (N‐DMBI) as the dopant. Ultimately, the polymer with CN substituents delivered the best thermoelectric performance with a power factor of up to 2.14 μW·m−1·K−2, because it possessed the lowest LUMO energy level among the three CPs. This work highlights that the modulation of LUMO energy level is an effective strategy to optimize the thermoelectric performance of CPs.

Y-Type Non-Fullerene Acceptors with Outer Branched Side Chains and Inner Cyclohexane Side Chains for 19.36% Efficiency Polymer Solar Cells.

Raising the lowest unoccupied molecular orbital (LUMO) energy level of Y-type non-fullerene acceptors can increase the open-circuit voltage (Voc ) and thus the photovoltaic performance of the current top performing polymer solar cells (PSCs). One of the viable routes is demonstrated by the successful Y6 derivative of L8-BO with the branched alkyl chains at the outer side. This will introduce steric hindrance and reduce intermolecular aggregation, thus open up the bandgap and raise the LUMO energy level. To take further advantages of the steric hindrance influence on optoelectronic properties of Y6 derivatives, two Y-type non-fullerene acceptors of BTP-Cy-4F and BTP-Cy-4Cl are designed and synthesized by adopting outer branched side chains and inner cyclohexane side chains. An outstanding Voc of 0.937V is achieved in the D18:BTP-Cy-4F binary blend devices along with a power conversion efficiency (PCE) of 18.52%. With the addition of BTP-eC9 to extend the absorption spectral coverage, a remarkable PCE of 19.36% is realized finally in the related ternary blend devices, which is one of the highest values for single-junction PSCs at present. The results illustrate the great potential of cyclohexane side chains in constructing high-performance non-fullerene acceptors and their PSCs.

Simultaneously enhancing the photovoltaic parameters of ternary organic solar cells by incorporating a fused ring electron acceptor.

The ternary strategy has been recognized as an effective method to improve the photovoltaic performance of organic solar cells (OSCs). In ternary OSCs, the complementary or broadened absorption spectrum, optimized morphology, and enhanced photovoltaic performance could be obtained by selecting a third rational component for the host system. In this work, a fused ring electron acceptor named BTMe-C8-2F, which possesses a high-lying lowest unoccupied molecular orbital (LUMO) energy level and a complementary absorption spectrum to PM6:Y6, was introduced to a PM6:Y6 binary system. The ternary blend film PM6:Y6:BTMe-C8-2F showed high and more balanced charge mobilities, and low charge recombination. Therefore, the OSC based on the PM6:Y6:BTMe-C8-2F (1 : 1.2 : 0.3, w/w/w) blend film achieved the highest power conversion efficiency (PCE) of 17.68%, with an open-circuit voltage (VOC) of 0.87 V, a short-circuit current (JSC) of 27.32 mA cm-2, and a fill factor (FF) of 74.05%, which are much higher than the binary devices of PM6:Y6 (PCE = 15.86%) and PM6:BTMe-C8-2F (PCE = 11.98%). This work provides more insight into the role of introducing a fused ring electron acceptor with a high-lying LUMO energy level and complementary spectrum for simultaneously enhancing the VOC and JSC to promote the performance of ternary OSCs.

Third component with a high LUMO energy level enables 17.69% efficiency in ternary organic solar cells

The ternary strategy is thought to be a practical method for improving the power conversion efficiency (PCE) of organic solar cells (OSCs). To create ternary OSCs, a PM6:BTP-BO-4F host blend was combined with the non-fullerene small molecule acceptor BTA3, which has a high lowest unoccupied molecular orbital (LUMO). BTA3 demonstrated complementary absorption spectra and excellent compatibility with BTP-BO-4F, which made it easier to modulate the ternary film's morphology and catch more photons. As a result, the short circuit current density increased. Additionally, BTA3's LUMO level was marginally higher than BTP- BO-4F's, which led to a higher open-circuit voltage of the TOSCs. The addition of BTA3 improved the OSCs' energy transfer and phase separation, which in turn sped up charge transfer and reduced exciton recombination. The PCE of the TOSCs included with 10 wt% BTA3 rose to 17.69% in comparison to a PCE of 16.46% based on host binary OSCs. This research demonstrated that the incorporation of BTA3 with a high LUMO level enabled the fabrication of ternary OSCs with good performance.

Perylene-Mediated Electron Leakage in Respiratory Chain to Trigger Endogenous ROS Burst for Hypoxic Cancer Chemo-Immunotherapy.

Perylene derivatives can be stimulated by the hypoxic tumor microenvironment to generate radical anion that is proposed to arouse electron exchange with oxidizing substance, and in turn, realize reactive oxygen species (ROS) burst. Here, three perylene therapeutic agents, PDI-NI, PDIB-NI, and PDIC-NI, are developed and it is found that the minimum lowest unoccupied molecular orbital (LUMO) energy level makes PDIC-NI most easily accept electrons from the oxidative respiratory chain to form lots of anions, and the resultant maximum ROS generation, establishing an unambiguous mechanism for the formation of perylene radical anions in the cell, presents solid evidence for LUMO energy level determining endogenous ROS burst. Stirringly, PDIC-NI-induced ROS generation arouses enhanced mitochondrial oxidative stress and concurrently activates immunogenic cell death (ICD), which not only efficiently kills lung tumor cells but also reprograms immunosuppressive tumor microenvironment, including the cytokine secretion, dendritic cell maturation, as well as cytotoxic T lymphocytes activation, to inhibit the growth of xenografted and metastasis tumor, presenting a proof-of-concept demonstration of perylene that acts as an integrated therapeutic agent to well realize hypoxia-activated chemotherapy with ICD-induced immunotherapy on lung cancer.

Recent Advances in Selenophene-Based Materials for Organic Solar Cells.

Due to the low cost, light weight, semitransparency, good flexibility, and large manufacturing area of organic solar cells (OSCs), OSCs have the opportunity to become the next generation of solar cells in some specific applications. So far, the efficiency of the OSC device has been improved by more than 20%. The optical band gap between the lowest unoccupied molecular orbital (LUMO) level and the highest occupied molecular orbital (HOMO) level is an important factor affecting the performance of the device. Selenophene, a derivative of aromatic pentacyclic thiophene, is easy to polarize, its LUMO energy level is very low, and hence the optical band gap can be reduced. In addition, the selenium atoms in selenophene and other oxygen atoms or sulfur atoms can form an intermolecular interaction, so as to improve the stacking order of the active layer blend film and improve the carrier transport efficiency. This paper introduces the organic solar active layer materials containing selenium benzene in recent years, which can be simply divided into donor materials and acceptor materials. Replacing sulfur atoms with selenium atoms in these materials can effectively reduce the corresponding optical band gap of materials, improve the mutual solubility of donor recipient materials, and ultimately improve the device efficiency. Therefore, the sulfur in thiophene can be completely replaced by selenium or oxygen of the same family, which can be used in the active layer materials of organic solar cells. This article mainly describes the application of selenium instead of sulfur in OSCs.

A potential sensor for assessing thorium (IV) based on Albuterol sulfate fluorescence enhancement: A density functional theory (DFT) study

• Introducing a new fluorescent sensor for assessing Th(IV) in environmental samples. • Fluorescence mechanism was discussed. • HOMO and LUMO energy levels has been calculated by DFT. This study introduces a potential fluorescence sensor for assessing thorium (Th(IV)) in aquatic environments. In the presence of Th(IV), Albuterol Sulfate ( ABS ) 4-[2-( tert -butylamino)-1-hydroxyethyl]-2-(hydroxymethyl)phenol; sulfuric acid exhibits significant fluorescence enhancement at 600 nm. The current ABS ligand sensor shows wide linear range from 6.0 × 10 −8 – 2.5 × 10 −7 mol/L and pH range of 4–6. Interestingly, when all evaluated interference ions coexisted, the change in fluorescence emission intensity of ABS -Th complex was roughly 2.3 %. The binding mode is studied and indicating a 2:1 complex formation between ABS ligand and Th (IV). Density functional theory (DFT) has been utilized to examine the interaction characteristics between the present ABS ligand sensor and Th(IV) and to compute the geometric configuration of the ABS and ABS -Th through the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels. The interaction properties exhibit considerable effect on the HOMO and LUMO properties of the complexes, as well as a fluorescence enhancement that could be attributable to the heavy atom effect of Th (IV). The ABS sensor shows remarkable features and provides good performance compared to some of the optical sensors, making it a potential new fluorescence sensor for Th(IV) assessment.

Ternary organic photovoltaic using long wavelength light absorption polymer as guest donor with enhance photovoltaic performance

Ternary organic photovoltaics (OPVs) are fabricated by PTQ10 as donor materials, Y6 as an acceptor, and PTB7-Th as a guest donor. The lowest unoccupied molecular orbital (LUMO) energy levels of PTB7-Th are deeper than those of PTQ10, and a cascade of LUMO energy levels is formed among the different device materials. The PTQ10:Y6 binary OPVs show an open-circuit voltage (VOC) of 0.870 V, which is relatively higher than that obtained for the ternary OPVs. The decrease in the VOC of the ternary OPVs is mainly ascribed to an upshift in the HOMO energy levels of the blend donor and a narrow energy bandgap. The short-circuit current density (JSC) for the ternary OPVs can be increased from 25.07 mA cm−2 to 26.60 mA cm−2 with a PTB7-Th content of up to 15 wt%, which is mainly attributed to efficient photon harvesting and reduced charge recombination. Therefore, these results indicate that JSC and PCE can be significantly enhanced by the incorporation of PTB7-Th into PTQ10:Y6 binary films despite a significant decrease in VOC.

Hole-Transport Layer-Free Tin-Based Perovskite Solar Cells: Improving Their Performance from a Simulation Perspective

Perovskite solar cells are in rapid development, however, PCE (photovoltaic conversion efficiency) of HTL-free (Hole Transport Layer free) perovskite solar cells is reported to be low. In this work, we propose a tin-based perovskite solar cell with an ETL (Electron Transport Layer) structure of a novel electron transport layer material. We simulated the device with SCAPS-1D (Solar Cells Capacitance Simulator) and found that all of the absorber layer thickness, band gap, doping concentration, defect density, device working temperature, ETL layer thickness, and doping concentration have different degrees of influence on the device performance. After optimization, (Open Circuit Voltage) is 1.07 V, (Short-circuit Current Density) is 24.25 FF (Filling Factor) is 87.87%, and PCE arrives up to 22.72%. There is a significant performance improvement compared to pre-simulation (initially, is 0.97 V, is 24.21 FF is 69.12%, and PCE is 16.22%). It is shown that when the thickness of the absorber layer is larger than the diffusion length, it leads to harmful photogenerated carrier complexes and increases the diffusion length before reaching the electrode, which affects the carrier transport migration. Defect density bears the brunt of the performance impact, the greater it is the worse the performance, so it should be controlled to a small range. When the operating temperature higher than 300 K, the device performance tends to deteriorate and it is recommended to keep the operating temperature around 300 K. The ETL layer doping concentration and thickness have little influence on performance. Finally, we also analytically simulate and compare several traditional ETL PSCs, and the matching of LUMO (Lowest Unoccupied Molecular Orbital) and absorber energy levels of different ETL materials was found to be different, and the higher the matching is, the more favorable the electron transport and the higher the PCE. This work provides new strategy to design PSCs.

Towards Efficient Blue Delayed-Fluorescence Molecules by Modulating Torsion Angle Between Electron Donor and Acceptor

Towards Efficient Blue Delayed-Fluorescence Molecules by Modulating Torsion Angle Between Electron Donor and Acceptor

Synthesis of innovative triphenylamine-functionalized organic photosensitizers outperformed the benchmark dye N719 for high-efficiency dye-sensitized solar cells

Herein, we present a thorough photovoltaic investigation of four triphenylamine organic sensitizers with D–π–A configurations and compare their photovoltaic performances to the conventional ruthenium-based sensitizer N719. SFA-5–8 are synthesized and utilized as sensitizers for dye-sensitized solar cell (DSSC) applications. The effects of the donor unit (triphenylamine), π-conjugation bridge (thiophene ring), and various acceptors (phenylacetonitrile and 2-cyanoacetamide derivatives) were investigated. Moreover, this was asserted by profound calculations of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels, the molecular electrostatic potential (MEP), and natural bond orbital (NBO) that had been studied for the TPA-sensitizers. Theoretical density functional theory (DFT) was performed to study the distribution of electron density between donor and acceptor moieties. The sensitization by the absorption of sensitizers SFA-5–8 leads to an obvious enhancement in the visible light absorption (300–750 nm) as well as a higher photovoltaic efficiency in the range of (5.53–7.56%). Under optimized conditions, SFA-7 showed outstanding sensitization of nanocrystalline TiO2, resulting in enhancing the visible light absorption and upgrading the power conversion efficiency (PCE) to approximately 7.56% over that reported for the N719 (7.29%). Remarkably, SFA-7 outperformed N719 by 4% in the total conversion efficiency. Significantly, the superior performance of SFA-7 could be mainly ascribed to the higher short-circuit photocurrents (Jsc) in parallel with larger open-circuit voltages (Voc) and more importantly, the presence of different anchoring moieties that could enhance the ability to fill the gaps on the surface of the TiO2 semiconductor. That could be largely reflected in the overall enhancement in the device efficiency. Moreover, the theoretical electronic and photovoltaic properties of all studied sensitizers have been compared with experimental results. All the 2-cyanoacrylamide derivative sensitizers demonstrated robust photovoltaic performance.

A Low‐Potential and Stable Bis‐Dimethylamino‐Substituted Anthraquinone for pH‐Neutral Aqueous Redox Flow Batteries

AbstractQuinone‐based aqueous redox flow batteries (RFBs) have drawn much attention due to their high safety, two‐electron involvement, rapid reaction kinetics, property tunability, and potentially low cost. RFBs operating in neutral solution feature a wide electrochemical window of around 2.5 V, which provides much more space for the design of redox‐active materials (RAMs) to realize a high voltage. However, it is still challenging to achieve low potential in the neutral condition for quinone‐based RAMs, owing to inherently pH‐dependent behaviors and deep LUMO (the lowest unoccupied molecular orbital) energy level. Herein, we report three low‐potential quinone‐based RAMs (1,4‐BDPAQCl2, 1,5‐BDPAQCl2, and 1,8‐BDPAQCl2) by bis‐dimethylamino substitution. The half‐wave potential of the quinones in 0.5 M KCl is approximately −0.55 to −0.57 V versus a normal hydrogen electrode. The low potential is ascribed to the introduced functional groups with two effects. First, the intramolecular hydrogen bonds formed between C=O and H−N can weaken the association between protons and dianion Q2−, resulting in a favorable distribution of products. Second, the functional groups can effectively increase the LUMO over 0.22 eV, compared with anthraquinone. Paired with Fe(glycine)2Cl2, the theoretical open‐circuit voltage of full RFBs is achieved at 1.27–1.29 V. We test full batteries using these quinones as negative RAMs at a lower concentration (0.1 M). The results show that 1,8‐BDPAQCl2 displays stability during 300 charge‐discharge cycles. In contrast, the other two quinones exhibit poor cycling stability due to side reactions. We further execute a higher concentration (0.4 M) for 1,8‐BDPAQCl2. The cycling stability of the quinone−iron RFBs is outstanding, with 0.048 % capacity decay per cycle and 0.88 % capacity decay per day. Our finding offers a feasible strategy to design low‐potential quinone molecules for the neutral RFBs.