Thiocarbonyl-Based Hole Transport Materials with Enhanced Defect Passivation Ability for Efficient and Stable Perovskite Solar Cells.

Organic hole transporting materials (HTMs) are extensively studied in perovskite solar cells (PSCs). The HTMs directly contact the underlying perovskite material, and they play additional roles apart from hole transporting. Developing organic HTMs with defect passivation function has been proved to be an efficient strategy to construct efficient and stable PSCs. In this work, new organic molecules with thiocarbonyl (C═S) and carbonyl (C═O) functional groups are synthesized and applied as HTMs (named FN-S and FN-O). FN-S with C═S can be facilely obtained from FN-O containing C═O. Notably, the C═S in FN-S results in superior defect passivation ability compared to FN-O. Moreover, FN-S exhibits excellent hole extraction/transport capability. Conventional PSCs using FN-S as HTM show an impressive power conversion efficiency (PCE) of 23.25%, with excellent long-term stability and operational stability. This work indicates that simply converting C═O to C═S is an efficient way to improve the device performance by strengthening the defect passivation functionality.

Tetrathiafulvalene Carboxylate-Based Anode Material for High-Performance Sodium-Ion Batteries.

Organic electrode materials are promising to be applied in sodium ion batteries (SIBs) due to their low cost and easily modified molecular structures. Nevertheless, low conductivity and high solubility in electrolytes still limit the development of organic electrodes. In this work, a carboxylate small molecule (BDTTS) based on tetrathiafulvalene is developed as anode material for SIBs. BDTTS has a large rigid π-conjugated planar structure, which may reduce solubility in the electrolyte, meanwhile facilitating charge transporting. Experimental results and theoretical calculations both support that apart from the four carbonyl groups, the sulfur atoms on tetrathiafulvalene also provide additional active sites during the discharge/charge process. Therefore, the additional active sites can well compensate for the capacity loss caused by the large molecular weight. The as-synthesized BDTTS electrode renders an excellent capacity of 230 mAh g-1 at a current density of 50 mA g-1 and an excellent long-life performance of 128 mAh g-1 at 2 C after 500 cycles. This work enriches the study on organic electrodes for high-performance SIBs and paves the way for further development and utilization of organic electrodes.

Joinpoint regression analysis of recent trends in desmoplastic malignant melanoma incidence and mortality: 15-year multicentre retrospective study.

BACKGROUND: Recent data reveal a marked rise in the detection and mortality rates of Desmoplastic Malignant Melanoma (DMM). This trend underscores the imperative for an in-depth analysis of DMM's epidemiology, which is crucial for the formulation of precise medical and public health strategies. This investigation seeks to elucidate the variations in the incidence and mortality of DMM over a 15-year period (2005-2019). METHODS: Data on DMM patients was sourced from the Surveillance, Epidemiology, and End Results (SEER) database. Both incidence and incidence-based mortality rates (IBM) were directly extracted from the SEER database. Joinpoint regression was used to analyze and calculate the average annual percent change (AAPC) and its 95% confidence interval (CI). RESULTS: Between 2005 and 2019, 3,384 DMM cases were identified, boasting an age-adjusted incidence rate of 36.3 cases per 1000,000 person-years (95% CI 3.51-3.76) and an IBM of 1.65cases per 1000,000 person-years (95% CI 1.57-1.74). Of these, 2,353 were males (69.53%) and 1,031 were females (30.47%). There were 1894 patients (55.97%) who were over 70 years old. Predominantly, DMM lesions manifested in exposed areas: Limbs (955, 28.22%), Face (906, 26.77%), and Scalp and Neck (865, 25.56%). The incidence of DMM increased significantly at a rate of APC = 0.9% during 2005-2019, while the incidence-based mortality showed a significant upward trend (APC = 7%) during 2005-2012, and slowly increasing trend (APC = 0.6%) during 2012-2019. In contrast to the modest upward trajectory in female incidence and mortality, male incidence initially surged, later declining, while male mortality peaked and stabilized post-2012. The primary sites for incidence and mortality were chronically sun-exposed areas: Face, Scalp and Neck, and Limbs. CONCLUSIONS: In recent years, the incidence and incidence-based mortality of DMM have significantly increased. Each subgroup analysis has different trends, and these trends can provide better support for our exploration of DMM.

Organic Semiconductor Based on N, S-Containing Crown Ether Enabling Efficient and Stable Perovskite Solar Cells.

The uncoordinated lead cations are ubiquitous in perovskite films and severely affect the efficiency and stability of perovskite solar cells (PSCs). In this work, 15-crown-5 with various heteroatoms are connected to the organic semiconductor carbazole diphenylamine, and two new compounds, CDT-S and CDT-N, are developed to modify the Pb2+ defects in perovskite films through the anti-solvent method. Apart from the oxygen atoms, there are also N atoms on crown ether ring in CDT-N, and both S and N heteroatoms in CDT-S. The heteroatoms enhance the interaction between the crown ether-based semiconductors and the undercoordinated Pb2+ defect in perovskite. Particularly, the stronger interaction between S atoms and Pb2+ further enhances the defect passivation effect of CDT-S than CDT-N, thereby more effectively suppressing the non-radiative recombination of charge carriers. Finally, the efficiency of the device treated with CDT-S is up to 23.05 %. Moreover, the unencapsulated device based on CDT-S maintained 90.5 % of the initial efficiency after being stored under dark conditions for 1000 hours, demonstrating good long-term stability. Our work demonstrates that crown ethers are promising in perovskite solar cells, and the crown ether containing multiple heteroatoms could effectively improve both efficiency and stability of devices.

In situ composition of Thienothiophene-based covalent organic framework on carbon nanotube as a host for high performance Li-S batteries.

Lithium-sulfur batteries (LSBs) is a promising secondary battery system with high energy density and environment-friendly characteristics, however, the severe "shuttle effect" and poor conductivity usually lead to short service life and low initial capacity. Carbon Nanotubes (CNTs) with excellent conductivity and large quantity of cavities are promising host materials, whereas, the weak interaction between CNTs and polysulfides usually leads to serious shuttle effect in charge/discharge processes. Herein, thienothiophene-based covalent organic framework is uniformly wrapped on the outer surface of CNTs to form a nanocomposite TT-BOST@CNT. It is observed that the coexistence of the electron-rich S, O and the electron-deficient B atoms enables the effective adsorption of both Li+ and Sx2- in lithium polysulfides (LiPSs). Studies reveal that the B, O and S atoms endow the nanocomposite with good catalysis ability, whereby, conversion of the insoluble long-chain polysulfides to the soluble short-chain polysulfides is accelerated. Consequently, the TT-BOST@CNT/S cathode displays outstanding electrochemical performance, with a high discharge specific capacity of 1545 mAh g-1 at 0.2 C and a small attenuation rate of 0.035% per cycle in 1000 cycles at 1 C.

Associations of pre- and postnatal exposures with optic nerve status in young adults.

PURPOSE: We aimed to explore the effect of multiple pre- and postnatal exposures on optic nerve status in young adults due to this critical period for development. METHODS: We analysed peripapillary retinal nerve fibre layer (RNFL) status and macular thickness at age 18 years in the Copenhagen Prospective Studies on Asthma in Childhood 2000 (COPSAC2000 ) cohort in relation to several exposures. RESULTS: Of the 269 participants (median (IQR) age, 17.6 (0.6) years; 124 boys), 60 participants whose mothers had smoked during pregnancy had a thinner RNFL: adjusted mean difference -4.6 µm (95% CI -7.7; -1.5 µm, p = 0.004) compared with participants whose mothers had not smoked during pregnancy. A total of 30 participants who were exposed to tobacco smoke both during foetal life and childhood had thinner RNFL: -9.6 µm (-13.4; -5.8 µm, p < 0.001). Smoking during pregnancy was also associated with a macular thickness deficit: -4.7 µm (-9.0; -0.4 µm, p = 0.03). Higher indoor concentrations of particulate matter 2.5 (PM2.5) was associated with thinner RNFL: -3.6 µm (-5.6; -1.6 µm, p < 0.001) and a macular deficit: -2.7 µm (-5.3; -0.1 µm, p = 0.04) in the crude analyses, but not in the adjusted analyses. No difference was found among participants who smoked at age 18 years compared with non-smokers on RNFL or macular thickness. CONCLUSIONS: We found that exposure to smoking during early life was associated with a thinner RNFL and macula at age 18 years. The absence of an association between active smoking at 18 years suggests that the vulnerability of the optic nerve is highest during prenatal life and early childhood.

Adjusting morphological properties of organic electrode material for efficient Sodium-ion batteries by isomers strategy.

In this work, two isomers are mixed in different proportions and then alkalized as the organic anode material for sodium-ion batteries (SIBs). The mixed material, denoted as PN, shows distinct morphology and electrochemical properties, compared to the single-component Na-CPP and Na-CPN. The Initial Coulombic Efficiency (ICE) value obtained by using the mixed PN as anode is higher than that using the single component. And the capacity retention rate of the mixed PN electrode is 92% after 1200 cycles under 935 mA g-1 high current density. This is mainly due to the superior morphology of the mixed PN electrode (the optimal ratio is CPP: CPN = 3: 1, the mass ratio (or molar ratio)), which exhibits more uniform spherical particles, thus increasing the contact area with the electrolyte and ensuring close contact with the conductive carbon. As a result, the ICE and cycle performance is improved because of the reduced irreversible side reactions. As far as we know, this is the first example of mixing two isomers as organic anode materials in traditional SIBs, and this strategy may provide new insights into future development of organic electrode materials.

Clinical Value of Three Combined Ultrasonography Modalities in Predicting the Risk of Metastasis to Axillary Lymph Nodes in Breast Invasive Ductal Carcinoma.

OBJECTIVE: The present study aimed to assess the clinical value of conventional ultrasound (C-US), ultrasound elastography (UE), percutaneous contrast-enhanced ultrasound (P-CUES), and the combination of these three ultrasonography modalities for evaluating the risk of axillary lymph node (ALN) metastasis in breast invasive ductal carcinoma (IDC). METHODS: This retrospective analysis included 120 patients with pathologically confirmed IDC who underwent sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND). Based on the gold standard of postoperative pathology, ALN pathology results were evaluated and compared with findings obtained using C-US, UE, P-CUES, and the three modalities combined. RESULTS: (1) There was a statistically significant difference between the histological grade of the tumor and the pathological condition of ALNs. (2) The difference between C-US parameters and UE score were statistically significant. The accuracy of P-CEUS localization of SLNs was 100% (96/96) when compared with localization guided by methylene blue. The difference in the distribution of the four SLN enhancement patterns was statistically significant. (3) The sensitivity, specificity, positive predictive value, and negative predictive value of C-US and UE were 75%, 71%, 58%, and 89%, and 71%, 72%, 50%, and 86%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of P-CUES were 91%, 82%, 78%, 92%, respectively. When all three modalities were combined, the sensitivity, specificity, positive predictive value, and negative predictive value were 94%, 89%, 86%, and 95%, respectively. In the detection of ALN metastasis, there was a good correlation between histopathological results and evaluations based on the three combined ultrasonography modalities (kappa: 0.82, p<0.001). CONCLUSIONS: When compared to C-US, UE, or P-CEUS alone, the combination of the three ultrasonography modalities was found to be superior in distinguishing metastatic and non-metastatic ALNs. This combined strategy may aid physicians in determining the most appropriate approach to ALN surgery as well as the prognosis of breast IDC.

Moderate Exercise Combined with Enriched Environment Enhances Learning and Memory through BDNF/TrkB Signaling Pathway in Rats.

This study aimed to investigate the effects and potential mechanisms of exercise combined with an enriched environment on learning and memory in rats. Forty healthy male Wistar rats (7 weeks old) were randomly assigned into 4 groups (N = 10 in each group): control (C) group, treadmill exercise (TE) group, enriched environment (EE) group and the TE + EE group. The Morris water maze (MWM) test was used to evaluate the learning and memory ability in all rats after eight weeks of exposure in the different conditions. Moreover, we employed enzyme-linked immunosorbent assay (ELISA) to determine the expression of brain-derived neurotrophic factor (BDNF) and receptor tyrosine kinase B (TrkB) in the rats. The data showed that the escape latency and the number of platform crossings were significantly better in the TE + EE group compared to the TE, EE or C groups (p < 0.05). In addition, there was upregulation of BDNF and TrkB in rats in the TE + EE group compared to those in the TE, EE or C groups (p < 0.05). Taken together, the data robustly demonstrate that the combination of TE + EE enhances learning and memory ability and upregulates the expression of both BDNF and TrkB in rats. Thus, the BDNF/TrkB signaling pathway might be modulating the effect of exercise and enriched environment in improving learning and memory ability in rats.

Unfused Electronic Acceptor-Based Polymers as Interfacial Materials for Efficient Inverted Perovskite Solar Cells.

The interfacial issue resulting from surface trap states has become the crucial factor that limits the development of inverted perovskite solar cells (PSCs). Here, three unfused electronic acceptor-based polymers (PC-1-PC-3) with tailored alkyl groups were designed as interfacial materials to modify the interface contact between the perovskite active layer and electron transporting layer (ETL). Among them, PC-2 was found to extract interfacial charge faster and passivate trap states more efficiently. This leads to a remarkable increase in the short-circuit current density (22.49 mA cm-2) and fill factor (0.821), as well as a maximum power conversion efficiency of 20.50% with a negligible hysteresis, which is superior to the PC-1/PC-3 based devices and reference device with only the ETL. This study provides an insight for future molecular design of efficient interfacial materials for inverted PSCs.

Phenylpyridine Dicarboxylate as Highly Efficient Organic Anode for Na-Ion Batteries.

The sodium-ion battery (SIB) has the potential to be the next-generation rechargeable system, utilizing cheap and abundant sodium material. One of the key obstacles to sodium batteries is the lack of efficient and stable anode materials. Compared with traditional inorganic electrode materials, organic materials are more attractive because of their easier sodium transport accessibility and the diversities of organic frameworks and functional groups. In this work, two molecules (Na-CPN and Na-CPP) were synthesized and used as anode materials for SIBs. Structurally, the two compounds are isomers, and they are distinguished by the position of N atoms in phenylpyridine. Na-CPP showed a high reversible capacity of 197 mAh g-1 , and its capacity could maintain 99.1 % of its initial value even after 350 cycles of 100 mA g-1 . Moreover, after going through 1200 cycles at a current density of 5 C, the Na-CPP electrode still retained a capacity rate of 89.9 %. In contrast, Na-CPN exhibited inferior capacity and rate performance because of its larger polarization, particle size, and charge transport resistance.

Dopant-Free Organic Hole-Transporting Material for Efficient and Stable Inverted All-Inorganic and Hybrid Perovskite Solar Cells.

Designing new hole-transporting materials (HTMs) with desired chemical, electrical, and electronic properties is critical to realize efficient and stable inverted perovskite solar cells (PVSCs) with a p-i-n structure. Herein, the synthesis of a novel 3D small molecule named TPE-S and its application as an HTM in PVSCs are shown. The all-inorganic inverted PVSCs made using TPE-S, processed without any dopant or post-treatment, are highly efficient and stable. Compared to control devices based on the commonly used HTM, PEDOT:PSS, devices based on TPE-S exhibit improved optoelectronic properties, more favorable interfacial energetics, and reduced recombination due to an improved trap passivation effect. As a result, the all-inorganic CsPbI2 Br PVSCs based on TPE-S demonstrate a remarkable efficiency of 15.4% along with excellent stability, which is the one of the highest reported values for inverted all-inorganic PVSCs. Meanwhile, the TPE-S layer can also be generally used to improve the performance of organic/inorganic hybrid inverted PVSCs, which show an outstanding power conversation efficiency of 21.0%, approaching the highest reported efficiency for inverted PVSCs. This work highlights the great potential of TPE-S as a simple and general dopant-free HTM for different types of high-performance PVSCs.

Highly efficient inverted perovskite solar cells incorporating P3CT-Rb as a hole transport layer to achieve a large open circuit voltage of 1.144 V.

Poly[3-(4-carboxybutyl)thiophene-2,5-diyl] (P3CT) has been noticed as a promising hole transport layer (HTL) for high-performance inverted planar perovskite solar cells (PSCs) due to its excellent stability and relatively high hole mobility. As we all know, the morphology of perovskite films is largely influenced by the substrate materials. Considering the affinity of alkali metal ions Rb+ and Cs+ with perovskite materials, inverted perovskite solar cells using alkali metal ion (Rb+, Cs+) doped P3CT (denoted as P3CT-Rb and P3CT-Cs) as the HTLs were investigated in this work. It turned out that the work function (WF) of P3CT-Rb matches well with the valence band of perovskites. The perovskite (MAPbI3-xClx) film deposited on top of the P3CT-Rb film exhibited a dense and uniform morphology with superior crystallinity and few pinholes. Consequently, a high efficiency of 20.52% was achieved for P3CT-Rb HTL-based devices, with an impressive open-circuit voltage (Voc) of 1.144 V and a high fill factor (FF) of 82.78%.

A structure-property study of fluoranthene-cored hole-transporting materials enables 19.3% efficiency in dopant-free perovskite solar cells.

To date, most of the prevailing organic hole-transporting materials (HTMs) used in perovskite solar cells (PVSCs), such as spiro-OMeTAD and PTAA, generally require a sophisticated doping process to ensure their reasonable hole-transporting properties. Unfortunately, the employed dopants/additives and the associated oxidation reactions have been shown to deteriorate the long-term device stability seriously. The exploitation of efficient and stable dopant-free HTMs is thus strongly desired for PVSCs. However, effective molecular design strategies for dopant-free HTMs are still lacking. Thus far, only a few of them yielded comparable performance to their doped counterparts, while their synthetic costs are still high. In this work, a new class of cost-effective small molecule dopant-free HTMs have been developed using readily available fluoranthene as the structural framework. The structure-property correlation of the fluoranthene-based HTMs was carefully investigated by tuning their structural geometry (linear vs. branched), connection between electron-donating and electron-withdrawing moieties (single bond vs. ethylene), and the substitution position of the methoxy side-groups (para- vs. meta-). As a result, the optimized molecule, FBA3, was demonstrated to serve as an efficient dopant-free HTM in a conventional PVSC to deliver an impressive power conversion efficiency of 19.27%, representing one of the best cost-effective dopant-free organic HTMs reported thus far.

Designing a Perylene Diimide/Fullerene Hybrid as Effective Electron Transporting Material in Inverted Perovskite Solar Cells with Enhanced Efficiency and Stability.

Electron transport materials (ETM) play an important role in the improvement of efficiency and stability for inverted perovskite solar cells (PSCs). This work reports an efficient ETM, named PDI-C60 , by the combination of perylene diimide (PDI) and fullerene. Compared to the traditional PCBM, this strategy endows PDI-C60 with slightly shallower energy level and higher electron mobility. As a result, the device based on PDI-C60 as electron transport layer (ETL) achieves high power conversion efficiency (PCE) of 18.6 %, which is significantly higher than those of the control devices of PCBM (16.6 %) and PDI (13.8 %). The high PCE of the PDI-C60 -based device can be attributed to the more matching energy level with the perovskite, more efficient charge extraction, transport, and reduced recombination rate. To the best of our knowledge, the PCE of 18.6 % is the highest value in the PSCs using PDI derivatives as ETLs. Moreover, the device with PDI-C60 as ETL exhibits better device stability due to the stronger hydrophobic properties of PDI-C60 . The strategy using the PDI/fullerene hybrid provides insights for future molecular design of the efficient ETM for the inverted PSCs.

Core Structure Engineering in Hole-Transport Materials to Achieve Highly Efficient Perovskite Solar Cells.

In this work, the thiadiazolopyridine (PT) unit was introduced as the core structure, with N3 ,N3 ,N6 ,N6 -tetrakis(4-methoxyphenyl)-9-phenyl-9 H-carbazole-3,6-diamine as the peripheral group, to obtain a new compound, JY8, for use as a hole-transport material (HTM) in planar perovskite solar cells (PSCs). Compared with the previously reported JY5 with benzothiadiazole as the core structure, the PT unit with stronger electron-withdrawing ability enhanced the intermolecular dipole-dipole interaction. Moreover, the introduction of the PT unit made the central part in JY8 more planar than its analogue JY5, which is conducive to charge transport. Field-emission (FE)-SEM images suggested a smooth and condense morphology of the JY8 film, which could improve the contact between the perovskite layer and the metal electrode. Space-charge limitation of current results, steady-state, and time-resolved photoluminescence decay curves indicated that JY8 as HTM facilitated hole extraction and hole transport. Consequently, planar PSCs fabricated with JY8 as the HTM exhibited a decent efficiency of 19.14 % with a high fill factor of 81 %.

Spontaneously hierarchical self-assembly of nanofibres into fluorescent spherical particles: a leap from organogels to macroscopic solid spheres.

The spontaneous hierarchical self-assembly of organic small molecules into macroscopic architectures with excellent photophysical properties and highly-ordered structures has rarely been reported to date. In this work, we find that the organogel of SY1 formed in ethyl acetate could spontaneously assemble into macroscopic spherical particles with a unique morphology and photophysical properties. Upon increasing the aging time, the gel gradually collapsed and then transformed into many macroscopic spheres (SY1-balls) with an average diameter of ca. 500 µm and strong yellow emission. In view of the emission properties and the porous structure of the SY1-balls, they were successfully applied in the adsorption and detection of heavy metal ions. More interestingly, SY1 shows different assembly behaviours in toluene solution when mixed with a triphenylamine derivative (TPA1). Macroscopic particles (ST-balls) with a core-shell structure were obtained, which were quite different from the SY1-balls in morphology and emission colour. So far as we know, many studies have focused on the change of the micromorphology of a gel, while the spontaneous self-assembly of organogels into macroscopic particles has been reported in this work for the first time. This work enriches the present study on organogels and plays an important role in further understanding the hierarchical self-assembly of organogels.

Naphthodiperylenetetraimide-Based Polymer as Electron-Transporting Material for Efficient Inverted Perovskite Solar Cells.

An n-type conjugated polymer NDP-V [poly(naphthodiperylenetetraimide-vinylene)] with a backbone of alternating naphthodiperylenetetraimide and vinylene is successfully used as an efficient electron-transporting layer (ETL) material in inverted planar perovskite solar cells (PSCs). It was found that device based on NDP-V exhibits a maximum power conversion efficiency (PCE) of 16.54%, whereas a maximum PCE of 15.27% is obtained based on the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM). The interfacial effect induced by NDP-V is studied using atomic force microscopy images, and NDP-V ensures good selective contact between the perovskite material and the metal electrode. Through steady-state and time-resolved photoluminescence, we find that NDP-V acts as an efficient electron extraction material. Additionally, compared with PC61BM, NDP-V shows higher electron mobility, more hydrophobicity, and compatible energy levels with perovskite materials, thus providing higher device performance and better device stability. This work highlights the great potential of perylenediimide derivatives to replace the most popular PC61BM ETL for inverted PSCs.

A new red fluorophore with aggregation enhanced emission by an unexpected "One-step" protocol.

In this work, a triphenylamine-benzothiadiazole-based new fluorophore is obtained from a facile "one-step" protocol. A possible reduction mechanism is proposed, and an amine containing α-H plays a key role in the reduction reaction. The resultant product A1H2 exhibits bright red emission in solid state, with an absolute quantum yield of 44.5%. Aggregation induced emission enhancement of A1H2 is also observed with the increased water fraction in THF-H2O mixture. The nanoparticles of A1H2 reveal good stability and biocompatibility, which are successfully applied in cellular cytoplasm imaging.

Fluorine-substituted benzothiadiazole-based hole transport materials for highly efficient planar perovskite solar cells with a FF exceeding 80.

Fluorine-substituted benzothiadiazole (BT) was introduced as a core structure to construct new hole transport materials. Planar perovskite solar cells with conventional materials (CH3NH3PbI3-xClx) were fabricated. The perovskite solar cells using monofluorinated BT exhibit a leading efficiency of 18.54% with a FF as high as 81%.