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Carrier transport is an equally decisive factor as carrier separation for elevating photocatalytic efficiency. However, limited by indefinite structures and low crystallinities, studies on enhancing carrier transport of organic photocatalysts are still in their infancy. Here, we develop an σ-linkage length modulation strategy to enhance carrier transport in imidazole-alkyl-perylene diimide (IMZ-alkyl-PDI, corresponding to D-σ-A) photocatalysts by controlling π-π stacking distance. Ethyl-linkage can shorten π-π stacking distance (3.19â Å) the most among IMZ-alkyl-PDIs (where alkyl=none, ethyl, and n-propyl) via minimizing steric hindrance between D and A moieties, which leads to the fastest carrier transport rates. Thereby, IMZ-ethyl-PDI exhibits remarkable enhancement in phenol degradation with 32-fold higher rates than IMZ-PDI, as well as the oxygen evolution rate (271-fold increased). In microchannel reactors, IMZ-ethyl-PDI also presents 81.5 % phenol removal with high-flux surface hydraulic loading (44.73â L m-2 h-1 ). Our findings provide a promising molecular design guideline for high-performance photocatalysts and elucidate crucial internal carrier transport mechanisms.
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The insufficient charge separation and sluggish exciton transport severely limit the utilization of polymeric photocatalysts. To resolve the above issues, we incorporate bountiful carboxyl substituents within a novel benzodiimidazole oligomer and assemble it into a crystalline semiconductor. The photocatalyst is polar, hydrophilic, short-range crystalline, and capable of both hydrogen and oxygen evolution. The introduction of carboxyl side-groups adds asymmetry to the local structure and increases the built-in electric field. Further, accelerated carrier transfer is enabled via the short-range crystallinity. The superior hydrogen and oxygen production rates of 18.63 and 2.87â mmol g-1 h-1 represent one of the best performances ever reported among dual-functional polymeric photocatalysts. Our work initiates studies on high-performance oligomer photocatalysts, opening a new frontier to produce solar fuel.
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Four isostructural donor-acceptor alternating polymers of benzodithiophene (BDT)/naphthodifuran (NDF) and benzoselenadiazole (BSe)/benzothiadiazole (BT) have been developed and evaluated for organic photovoltaics. The substitution of one-atom (Se for S) in the accepting units exerts remarkable impact on the optoelectronic properties of polymers. Extended absorption, narrowed bandgap and higher HOMO energy levels were observed for Se-containing polymers in comparison to their S-containing counterparts. Theoretical calculations confirmed the measurable effect on energy levels as found in experimental studies. Bulk-heterojuction solar cells based on the BDT-BSe copolymer and [6,6]-phenyl-C71-butyric acid methyl ester (1 : 2, w/w) blend films deliver the best PCE of 5.40%. BSe-based polymers showed enhanced photovoltaic performances than BT-based polymers. The device performance is found to be strongly dependent on the processing conditions and morphology of the active layers.
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Three dialkylthio benzo[1,2-b:4,5-b']dithiophene (S-BDT) based polymers have been developed using different accepting units to tune their bandgaps. The polymer:PC71BM solar cells achieved the highest power conversion efficiency (PCE) of 4.51% without any post-treatment (such as annealing and solvent additive) in conventional single-cell devices. Joint photophysical, electrical and computational studies on the polymer based solar cells revealed the considerable impact of molecular planarity on polymer design. The polymer:PC71BM devices processed with 1,8-diiodooctane for improving their morphology afforded an improved PCE value of 5.63%, with a Voc of 0.83, a Jsc of 10.24 mA cm(-2) and a FF of 66.3%.
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Due to the irregular of diet and overfeeding greasy and surfeit flavor closely associated with hyperuricemia disease, the lipid emulsion containing high cholesterol was used to model. To obtain a more stable and sustained animal model for the efficacy evaluation of traditional Chinese herbs, we observed the influence on the serum uric acid of rat induced by the lipid emulsion compared with high purine diet. 36 SD male rats were randomized to the normal control group, high purine diet group and lipid emulsion group respectively. The general behavior, body weight and daily food intake of rats were observed. The orbital blood was taken to separate into the serum and 24 hours urine was collected. The serum indexes such as UA, BUN, Cr, ALT, AST, TC, TG, LDL-c were determined every 2 weeks, and XOD, ADA enzyme activity were determined at the 4th week. The urine indexes such as UA, Cr and Cua/Ccr were determined at the 4th week. After stopping modeling, the serum UA were determined two weeks and four weeks later respectively. At the 2nd week, the body weight and daily food intake of rats in the lipid emulsion group reduced significantly, and the level of serum UA, BUN, Cr, TC, LDL-c, ATL, AST raised significantly meanwhile TG reduced. At the 4th week, the serum UA in high purine diet group did not raise, and the serum XOD raised obviously while ADA did not; the serum UA in lipid emulsion group was higher significantly, and the serum XOD and ADA raised while Cua/Ccr reduced obviously. At the 6th weeks, the serum UA in both the high purine diet group and lipid emulsion group raised obviously. After stopping modeling, the serum UA in lipid emulsion group still maintained a high level at the 2nd week and back to the normal level at the 4th week. Compared with high purine diet, the hyperuricemia model induced by lipid emulsion forms earlierand more stable. It maybe has great value to study the pharmacodynamics of traditional Chinese medicine treatment to hyperuricemia disease. Its mechanism may be related to increasing XOD and ADA enzyme activity which can promote uric acid synthesis, meanwhile inhibiting of uric acid excretion.
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Hiperuricemia/metabolismo , Metabolismo de los Lípidos , Animales , Dieta/efectos adversos , Modelos Animales de Enfermedad , Emulsiones/efectos adversos , Emulsiones/metabolismo , Humanos , Lípidos/química , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
OBJECTIVE: To observe the effect of composite factors, like long-term high-salt & fat diet and alcohol abuse on blood viscosity and blood pressure in rats, and compare with a model induced by high molecular dextran, in order to build a chronic hyperviscosity aminal model which is similar to human hyperviscosity in clinic and lay a foundation for efficacy evaluation on traditional Chinese medicines. METHOD: Male SD rats were randomly divided into the normal group, the high molecular dextran (HMD) group and the high salt & fat and alcohol (HSFA) group. The HMD group was given normal diet and water for 23 day and then 10% HMD through tail vein for 5 days. The HSFA group was fed with high salt and high fat diets every day and alcohol for 20 h x d(-1) for 13 weeks. After the modeling, whole blood viscosity and plasma viscosity were measured in the 5th, 8th and 11th week. Blood pressure was measured in the 5d, 7h, and 10th week. Red cell count (RBC) and hematocrit (HCT) were measured in the 11th week. PAgT, Fb, ET-1, NO, PGI, TXA2 contents of the normal group and the HSFA group were measured in the 13th week, and IECa21 content was measured with flow cytometry. Result: After the modeling, the HMD group was in good conditions with glossy hairs and active behaviors. The HSFA group was depressed with withered hairs and less activities. During the 5th-11th weeks, the HMD group and the HSFA group showed higher values in high and low shear whole blood viscosity (WBV) than the normal control group. The plasma viscosity (PV) of HMD rats was significantly increased only in the 5th week, and that of HSFA rats significantly increased in the 8"' and 11th week, particularly in the 11'h week. In the 111h week, the HSFA group showed significant increases in RBC and HCT. After the modeling, the blood pressure of HMD rats showed no significant changes, but the blood pressure of HSFA rats significantly increased during 7' and 101h weeks, particularly in the 10"' week. In the 13th week, PAgT, IECa2+, Fb, ET-1 of HSFA rats significantly increased, but with decreases in NO and PGI2. CONCLUSION: Long-term high salt & fat and alcohol diets can cause abnormal blood viscosity in rats. WBV significantly increased since the 5th week in rats, and PV increased since the 8th week. The mechanism for increasing BV may be: (1) increases in RBC, HCT, and IECa2+, (2) PAgT increase, (3) Fb content increase, or (4) TXA2/PGI2, ET-1/NO imbalance. Although the modeling time with the method is longer than that with the HMD method, the model is more stable and moderate, and could lead to abnormal increases in WBV and PV; Whereas the HMD method only induced transient increase in plasma viscosity and abnormal increase in SBP. The model is more similar to traditional Chinese medicine syndromes and pathogenesis, with higher value for studies on efficacy of traditional Chinese medicines.
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Alcoholismo/sangre , Viscosidad Sanguínea , Dieta Alta en Grasa/efectos adversos , Cloruro de Sodio Dietético/efectos adversos , Alcoholismo/metabolismo , Animales , Presión Sanguínea , Modelos Animales de Enfermedad , Etanol/efectos adversos , Etanol/metabolismo , Humanos , Masculino , Ratas , Ratas Sprague-Dawley , Cloruro de Sodio Dietético/metabolismoRESUMEN
A two-dimensional (2D) low bandgap polymer () based on dithieno[3,2-b:2',3'-d]silole (DTS) with phenyl substitution on the bridging silicon atom and thiazolo[5,4-d]thiazole (TTz) was designed and synthesized for photovoltaic applications. The impact of conjugated side chains on the optical, electrochemical and energy levels of the polymer was studied. The phenyl substituted DTS polymer exhibited a 0.16 eV down-shifted highest occupied molecular orbital (HOMO) energy level and ca. 0.1 eV narrowed bandgap in comparison to the corresponding polymers with alkyl substitution on the silicon bridge. The influence of the blend weight ratio, the PFN layer, mixed solvent, THF exposure and polar solvent treatment and thermal annealing on the performance of :PC71BM devices was studied. : PC71BM (1 : 1, weight ratio) devices delivered the highest power conversion efficiency of 2.14% by using the PFN layer and THF annealing. Thermal annealing was found to exert a negative effect on the device performance. The morphology evolution of blend films processed with different solvents explained the difference in device performance. The results indicate that phenyl substitution is an effective way to tune the HOMO and bandgap of polymer donors for enhanced photovoltaic performance with the as-demonstrated 2D-conjugated DTS structure.
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Herein, we present a distinct methodology for the in situ electrostatic assembly method for synthesizing a conjugated (IDT-COOH)/oxygen-doped g-C3N4 (O-CN) S-scheme heterojunction. The electron delocalization effect due to π-π interactions between O-CN and self-assembled IDT-COOH favors interfacial charge separation. The self-assembled IDT-COOH/O-CN exhibits a broadened visible absorption to generate more charge carriers. The internal electric field between the IDT-COOH and the O-CN interface provides a directional charge-transfer channel to increase the utilization of photoinduced charge carriers. Moreover, the active species (â¢O2-, h+, and 1O2) produced by IDT-COOH/O-CN under visible light play important roles in photocatalytic disinfection. The optimum 40% IDT-COOH/O-CN can kill 7-log of methicillin-resistant Staphylococcus aureus (MRSA) cells in 2 h and remove 88% tetracycline (TC) in 5 h, while O-CN only inactivates 1-log of MRSA cells and degrades 40% TC. This work contributes to a promising method to fabricate all-organic g-C3N4-based S-scheme heterojunction photocatalysts with a wide range of optical responses and enhanced exciton dissociation.
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Medical information extraction consists of a group of natural language processing (NLP) tasks, which collaboratively convert clinical text to pre-defined structured formats. This is a critical step to exploit electronic medical records (EMRs). Given the recent thriving NLP technologies, model implementation and performance seem no longer an obstacle, whereas the bottleneck locates on a high-quality annotated corpus and the whole engineering workflow. This study presents an engineering framework consisting of three tasks, i.e., medical entity recognition, relation extraction and attribute extraction. Within this framework, the whole workflow is demonstrated from EMR data collection through model performance evaluation. Our annotation scheme is designed to be comprehensive and compatible between the multiple tasks. With the EMRs from a general hospital in Ningbo, China, and the manual annotation by experienced physicians, our corpus is of large scale and high quality. Built upon this Chinese clinical corpus, the medical information extraction system show performance that approaches human annotation. The annotation scheme, (a subset of) the annotated corpus, and the code are all publicly released, to facilitate further research.
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Registros Electrónicos de Salud , Médicos , Humanos , China , Almacenamiento y Recuperación de la Información , Procesamiento de Lenguaje NaturalRESUMEN
Herein, A-D-A type indacenodithiophene-based small conjugated molecule IDT-COOH and IDT-COOH/TiO2 photocatalysts with stable non-covalent bonding have been successfully synthesized via in situ electrostatic assembly. The self-assembled three-dimensional π-conjugation structure IDT-COOH with high crystallinity not only broadens the visible absorption to produce more photogenerated carriers but also provides directional charge-transfer channels to accelerate the charge mobility. Thus, 7 log inactivation of S. aureus in 2 h and 92.5% decomposition of TC in 4 h under visible light exposure are achieved for optimized 30% IDT-COOH/TiO2. The dynamic constants (k) of S. aureus disinfection and TC degradation for 30% IDT-COOH/TiO2 are 3.69 and 2.45 times compared to those of self-assembled IDT-COOH, respectively. The notable inactivation performance is among the best reported for conjugated semiconductor/TiO2 photocatalysts for photocatalytic sterilization. ËO2-, e- and ËOH are the primary reactive species in the photocatalytic process. The strong interfacial interaction between TiO2 and IDT-COOH is in favour of rapid charge transfer, which leads to enhanced photocatalytic performance. This work offers a feasible method to fabricate TiO2-based photocatalytic agents with a wide visible light response and improved exciton dissociation.
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Desinfección , Staphylococcus aureus , Luz , SemiconductoresRESUMEN
Liver Cancer is a threat to human health and life over the world. The key to reduce liver cancer incidence is to identify high-risk populations and carry out individualized interventions before cancer occurrence. Building predictive models based on machine learning algorithms is an effective and economical way to forecast potential liver cancers. However, since the dataset is usually extremely skewed (negative samples are much more than positive samples), machine learning models suffer from severe bias and make unreliable predictions. In this paper, we systematically evaluate existing approaches in tackling class-imbalance problem and introduce two undersampling methods. The first is based on K-means++, where robust clustering centers are appointed as negative samples. The second is based on learning vector quantization, which considers diagnostic labels during clustering, and the prototypes are used as negative data. In this way, positive and negative samples are rebalanced. The algorithm is applied to five-year liver cancer prediction in Early Diagnosis and Treatment of Urban Cancer project in China. We achieve an AUC of 0.76 when no clinical measure except for epidemiological information is used. Experimental results show the advantage of our method over existing oversampling, undersampling, ensemble algorithms, and state-of-the-art outlier detection algorithms. This work explores a feasible and practical roadmap to tackle skewed medical data in cancer prediction and benefits applications targeted to human health and well-being.
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Neoplasias Hepáticas , Aprendizaje Automático , Algoritmos , China , Análisis por Conglomerados , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/epidemiologíaRESUMEN
The low utilization of visible light and the fast recombination of photogenerated electron-hole pairs are the two intrinsic defects that have hindered the antibacterial applications of TiO2. The addition of organic photocatalytic agents to form heterojunctions with TiO2 powder can effectively address these problems. A novel linear conjugated polymer poly[(thiophene-ethylene-thiophene)-thiophene-3-carboxylic acid decyl ester] (PTCD) was successfully synthesized via Stille coupling polymerization. PTCD and TiO2 can form a heterojunction photocatalyst (PTCD/TiO2), and this product was characterized using NMR and XRD. The UV-vis spectra showed that the absorption edge of the PTCD/TiO2 heterojunction extends to approximately 700 nm, which indicates that the visible-light utilization is greatly improved. Staphylococcus aureus (S. aureus) was selected as the target organism to test the photocatalytic antimicrobial activity of the material. Photogenerated electrons can undergo directional transmission of the PTCD polymer to TiO2 on the PTCD/TiO2 heterojunction to realize excellent antibacterial properties. With an optimized PTCD loading ratio of 30%, PTCD/TiO2 showed an antibacterial rate that was 14.5 times greater than that of pure TiO2 in 4 h under visible-light irradiation.
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Polímeros , Staphylococcus aureus , Antibacterianos/farmacología , Catálisis , Luz , Polímeros/farmacología , Tiofenos/farmacología , TitanioRESUMEN
With the renaissance of deep learning, automatic diagnostic algorithms for computed tomography (CT) have achieved many successful applications. However, they heavily rely on lesion-level annotations, which are often scarce due to the high cost of collecting pathological labels. On the other hand, the annotated CT data, especially the 3-D spatial information, may be underutilized by approaches that model a 3-D lesion with its 2-D slices, although such approaches have been proven effective and computationally efficient. This study presents a multiview contrastive network (MVCNet), which enhances the representations of 2-D views contrastively against other views of different spatial orientations. Specifically, MVCNet views each 3-D lesion from different orientations to collect multiple 2-D views; it learns to minimize a contrastive loss so that the 2-D views of the same 3-D lesion are aggregated, whereas those of different lesions are separated. To alleviate the issue of false negative examples, the uninformative negative samples are filtered out, which results in more discriminative features for downstream tasks. By linear evaluation, MVCNet achieves state-of-the-art accuracies on the lung image database consortium and image database resource initiative (LIDC-IDRI) (88.62%), lung nodule database (LNDb) (76.69%), and TianChi (84.33%) datasets for unsupervised representation learning. When fine-tuned on 10% of the labeled data, the accuracies are comparable to the supervised learning models (89.46% versus 85.03%, 73.85% versus 73.44%, 83.56% versus 83.34% on the three datasets, respectively), indicating the superiority of MVCNet in learning representations with limited annotations. Our findings suggest that contrasting multiple 2-D views is an effective approach to capturing the original 3-D information, which notably improves the utilization of the scarce and valuable annotated CT data.
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It is vital to develop general models that can be shared across subjects and sessions in the real-world deployment of electroencephalogram (EEG) emotion recognition systems. Many prior studies have exploited domain adaptation algorithms to alleviate the inter-subject and inter-session discrepancies of EEG distributions. However, these methods only aligned the global domain divergence, but overlooked the local domain divergence with respect to each emotion category. This degenerates the emotion-discriminating ability of the domain invariant features. In this paper, we argue that aligning the EEG data within the same emotion categories is important for generalizable and discriminative features. Hence, we propose the dynamic domain adaptation (DDA) algorithm where the global and local divergences are disposed by minimizing the global domain discrepancy and local subdomain discrepancy, respectively. To tackle the absence of emotion labels in the target domain, we introduce a dynamic training strategy where the model focuses on optimizing the global domain discrepancy in the early training steps, and then gradually switches to the local subdomain discrepancy. The DDA algorithm is formally implemented as an unsupervised version and a semi-supervised version for different experimental settings. Based on the coarse-to-fine alignment, our model achieves the average peak accuracy of 91.08%, 92.89% on SEED, and 81.58%, 80.82% on SEED-IV in the cross-subject and cross-session scenarios, respectively.
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Electroencefalografía , Emociones , Humanos , Electroencefalografía/métodos , AlgoritmosRESUMEN
A novel SERS membrane is synthesized by combining metal lattice and surface enhanced Raman scattering (SERS) technology. Since R6G is a carcinogenic and harmful pollutant, and traditional detection methods have many drawbacks and have research value, this paper selects R6G as the detection target. The SERS substrates are synthesized by loading Au nanoparticles (Au NPs) on the surface of polyvinylidene fluoride (PVDF) membrane. The Au NPs are synthesized through a controllable hydrothermal method. The synthesized AuNPs are covered by some gold particles, forming a fold pattern. Finally, the synthesized structure is immobilized on the surface of the PVDF membrane by the phase inversion method. It is suggested that the prepared Au NPs@PVDF membrane exhibits adjustable cavity structure, strong plasmon coupling, tunable magnetic plasmon resonance, prominent SERS performances. The prepared Au NPs@PVDF membrane showed sensitive SERS activity, good mechanical strength and reusability, expanding the application field of SERS detection. Overall, this study establishes a novel technique for the synthesis of SERS membrane with excellent SERS property and expands the application field of SERS detection.
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Oro , Nanopartículas del Metal , Polímeros de Fluorocarbono , Oro/química , Nanopartículas del Metal/química , Polivinilos , Plata/química , Espectrometría Raman/métodosRESUMEN
Selenium-heterocyclic and side-chain strategies for developing near-infrared (NIR) small fused-ring acceptors (FRAs) to further obtain short-circuit current density (Jsc) have proven advantageous in the top-performing polymer solar cells (PSCs). Herein, a new electron-rich central selenium-containing heterocycle core (BTSe) attaching alkyl side chains with a terminal phenyl group was coupled with a difluorinated and dichlorinated electron-accepting terminal 1,1-dicyanomethylene-3-indanone (IC) to afford two types of new FRAs, BTSe-IC2F and BTSe-IC2Cl. Interestingly, in spite of the weaker intramolecular charge transfer, BTSe-IC2F shows a stronger NIR response because of the smaller bandgap (Egopt) up to 1.26 eV, benefiting from the stronger ordered molecular packing in comparison to BTSe-IC2Cl with an Egopt of 1.30 eV. Additionally, thermal annealing induced an evident red shift by â¼50 nm in the absorption of D18:BTSe-IC2F blend films. Such a phenomenon may be attributed to the synergistic impact of the formation of inward constriction toward the molecular backbone because of the combination of bulky side chains and fluorinated IC as well as the reduced aromaticity of the selenium heterocycle. Consequently, the thermally annealed device based on BTSe-IC2F/D18 achieves a champion power conversion efficiency (PCE) of 17.3% with a high fill factor (FF) of 77.22%, which is among the highest reported PCE values for selenium-heterocyclic FRAs in binary PSCs. The improved Jsc and FF values of the D18:BTSe-IC2F film are simultaneously achieved mainly because of the preferred face-on orientations, the well-balanced electron/hole mobility, and the favorable blend morphology compared to D18:BTSe-IC2Cl. This work suggests that the selenium-heterocyclic fused-ring core (with proper side chains) combined with fluorinated terminal groups is an effective strategy for obtaining highly efficient NIR-responsive FRAs.
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Herein, a novel donor-acceptor (D-A) conjugated linear polymeric system, poly[(2,6-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-2,5-(3-carboxyl)-thiophene] (PBDT-F-COOH), with outstanding processing ability and its all-organic PBDT-F-COOH coating featuring chemical bonding for combination with polyurethane were prepared. Wide visible spectrum-driven PBDT-F-COOH and PBDT-F-COOH-PU showed dual efficient photocatalytic activities toward degradation and disinfection, mainly attributing to efficient dissociation of excitons and transfer of charge carriers, resulting from the large dipole moment of D-A PBDT-F-COOH. PBDT-F-COOH demonstrated >99.2% inactivation of Staphylococcus aureus (S. aureus) within 1 h and a 7-log decrease in 4 h under visible light irradiation. Additionally, the coating showed the 7-log inactivation of S. aureus in 7 h. These inactivation efficiency results are among those of the best reported D-A conjugated linear polymers. Importantly, PBDT-F-COOH and the PBDT-F-COOH-PU coating both presented satisfactory stability with high photocatalytic activity after recycling runs. This work provides a feasible approach for fabricating nontoxic and highly active organic photocatalysts with wide visible spectra and a large dipole moment via a D-A linear structure design protocol.
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Inspired by the structural advantages of spiro-OMeTAD, which is the most commonly used hole-transporting material (HTM), two rationally designed HTMs with butterfly-shaped triarylamine groups based on dibenzofulvene-bridged indacenodithiophene (IDT) core (attaching hexyl and octyl chains) have been synthesized, namely, IT-C6 and IT-C8, respectively. Shorter alkyl-chain-based IT-C6 exhibits a marked increase in glass-transition temperature (Tg) of 105 °C, whereas IT-C8 shows a Tg of 95 °C. Moreover, it is demonstrated that IT-C6 exhibits a higher hole-transporting mobility, more suitable band energy alignment, better interfacial contact, and passivation effect. The inverted devices of employed HTM based on IT-C6 obtained a champion PCE of 18.34% with a remarkable fill factor (FF) of 82.32%, whereas the IT-C8-based device delivered an inferior PCE of 16.94% with an FF up to 81.20%. Both HTMs embodied inverted devices present high FF values greater than 81%, which are among the highest reported values of small molecular HTM-based PSCs. This work reveals that cutting off the symmetrical spiro-core and subsequently combining IDT (attaching tailored alkyl chains) with the spiro-linkage fluorine to construct the orthogonal molecular conformation is a significant principle for the design of promising dopant-free HTMs.
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To design novel conjugated polymers and improve interfacial interaction with semiconductor is one of directions to develop high-efficient photocatalysts with harvesting photons and boosting catalytic activities. Herein, two novel linear conjugated polymers poly[(thiophene-ethylene-thiophene)-thiophene] (PTET-T) and poly[(thiophene-ethylene-thiophene)-thiophene-3-carboxylic acid] (PTET-T-COOH) were successfully synthesized by a simple Stille coupling reaction. Their heterojunction with TiO2, i.e, PTET-T/TiO2 (C1) and PTET-T-COOH/TiO2 (C2), exhibited outstanding photocatalytic activity for degrading Rhodamine B, methylene blue and tetracycline. The energetic "lock-in effect" between PTET-T-COOH and TiO2 through carboxyl groups and hydroxyl groups interaction has been proved to greatly improve the interface charge transfer ability and suppress the electron-hole recombination in PTET-T-COOH/TiO2. Thus, by regulating the dosage of polymers, the 15% PTET-T-COOH/TiO2 showed the optimized photocatalytic activity with excellent chemical stability, and its kinetic rate constant was determined to be 41.7 times of that of TiO2. This work provided a new effective strategy of designed and explored organic semiconductor-inorganic heterojunction photocatalysts with broaden absorption, repeatability and high-charge mobility.
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In this research work, we successfully fabricated a range of PTET-T-COOH/g-C3N4 heterostructures via a simple method. The as-prepared PTET-T-COOH/g-C3N4 heterostructures show enhanced photocatalytic degradation activity as compared to pure g-C3N4. For the photocatalytic degradation of RhB, the optimal PTET-T-COOH/g-C3N4-1% heterostructure is nearly 3.83 times that of the pure g-C3N4. The enhancement of photocatalytic performance is ascribed to three aspects: one is the strong interaction between PTET-T-COOH and g-C3N4; the second is the larger surface area of the PTET-T-COOH/g-C3N4 heterostructure compared to that of pure g-C3N4; the third is the effectively improved transferability of photogenerated carriers. In addition, the whole photocatalytic reaction mechanism over the PTET-T-COOH/g-C3N4 heterostructure is provided. This work may offer a hopeful method to synthesize any other heterostructure with high stability and superior photocatalytic activity.