Integrated System Built for Small-Molecule Semiconductors via High-Throughput Approaches.

High-throughput synthesis of solution-processable structurally variable small-molecule semiconductors is both an opportunity and a challenge. A large number of diverse molecules provide a possibility for quick material discovery and machine learning based on experimental data. However, the diversity of the molecular structure leads to the complexity of molecular properties, such as solubility, polarity, and crystallinity, which poses great challenges to solution processing and purification. Here, we first report an integrated system for the high-throughput synthesis, purification, and characterization of molecules with a large variety. Based on the principle "Like dissolves like," we combine theoretical calculations and a robotic platform to accelerate the purification of those molecules. With this platform, a material library containing 125 molecules and their optical-electronic properties was built within a timeframe of weeks. More importantly, the high repeatability of recrystallization we design is a reliable approach to further upgrading and industrial production.

Ginsenoside Rh2 inhibits metastasis of glioblastoma multiforme through Akt-regulated MMP13.

Glioblastoma multiforme (GBM) is the most malignant type of primary brain tumor. Although the growth of the tumor cells in a relatively closed space may partially account for its malignancy, highly invasive nature of glioblastoma cells has been suggested to be the main reason for the failure of current therapeutic approaches. Ginsenoside Rh2 (GRh2) has recently been shown to significantly suppress the growth and survival of GBM through inhibiting epidermal growth factor receptor signaling, whereas its effects on the invasion and metastasis have not been examined. Here, we showed that GRh2 dose-dependently decreased GBM cell invasiveness in both scratch wound healing assay and Transwell cell migration assay. Moreover, the inhibitory effects of GRh2 on cell migration seemed to be conducted through decreased expression of matrix metalloproteinase (MMP)-13. Furthermore, using specific inhibitors, we found that GRh2 inhibited MMP13 through PI3k/Akt signaling pathway. Finally, high MMP13 levels were detected in GBM specimen from the patients. Together, these data suggest that GRh2 may suppress GBM migration through inhibiting Akt-mediated MMP13 activation. Thus, our data highlight a previous unappreciated role for GRh2 in suppressing GBM cell metastasis.

Efficient and stabilized molecular doping of hole-transporting materials driven by a cyclic-anion strategy for perovskite solar cells.

Bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI) is commonly used as an effective dopant to improve the performance of the hole-transporting material (HTM) in n-i-p perovskite solar cells (PSCs). However, the ultra-hygroscopic and migratory nature of Li-TFSI leads to inferior stability of PSCs. Here, we report on a strategy to regulate the anion unit in Li-TFSI from linear to cyclic, constructing a new dopant, lithium 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide (Li-CYCLIC), for the state-of-the-art poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). Mechanistic and experimental results reveal that the cyclic anion CYCLIC- exhibits stronger interaction with Li+ and PTAA˙+ compared with the linear anion TFSI-, thus significantly restraining the moisture absorption and migration of Li+ and improving the thermodynamic stability of PTAA˙+CYCLIC-. With this molecular engineering, the resulting PSCs based on Li-CYCLIC obtained an improved efficiency, along with remarkably enhanced stability, retaining 96% of the initial efficiency after over 1150 hours under continuous 1 sun illumination in an N2 atmosphere, yielding an extrapolated T 80 of over 12 000 hours. In a broader context, the proposed strategy of linear-to-cyclic doping provides substantial guidance for the subsequent advancement in the development of effective dopants for photoelectric devices.

Incorporation of 2D pyreneammonium iodide for enhancing the efficiency and stability of perovskite solar cells.

Despite the excellent performance of three-dimensional (3D) perovskite-based solar cells (PSCs), their poor stability under moisture and heating conditions limits their commercial application. To address this issue, a new pyreneammonium iodide (named TAPPyI), in which the pyrene-based compound 4,4',4'',4'''-(1,8-dihydropyrene-1,3,6,8-tetrayl)tetraaniline (named TAPPy) acts as the 2D cation, is introduced into 3D perovskite precursor solution for forming a 2D/3D heterostructured perovskite, which improves the quality of the perovskite film and enhances the stability of the perovskite film against moisture and heating. The planar pyrene endows TAPPyI with good charge transport properties, while the iodide on the arylamine side group effectively passivates the perovskite defects, thereby suppressing non-radiative recombination losses. Finally, the power conversion efficiency (PCE) of the TAPPyI-modified PSC is increased from 20.51% in the reference PSC to 22.73%. Furthermore, the stability of the TAPPyI-modified PSC is greatly improved, retaining 86% of the initial PCE after 360 hours in an environment of 85 °C and 85% humidity (ISOS-D-3), whereas the reference PSC only retains 2%. This work demonstrates that the conjugated planar molecule as a 2D cation to construct a 2D/3D heterostructured perovskite, which combines the good stability of 2D perovskite with the excellent carrier transport properties of 3D perovskite, can greatly enhance the efficiency and stability of PSCs.

Polymer-acid-metal quasi-ohmic contact for stable perovskite solar cells beyond a 20,000-hour extrapolated lifetime.

The development of a robust quasi-ohmic contact with minimal resistance, good stability and cost-effectiveness is crucial for perovskite solar cells. We introduce a generic approach featuring a Lewis-acid layer sandwiched between dopant-free semicrystalline polymer and metal electrode in perovskite solar cells, resulting in an ideal quasi-ohmic contact even at elevated temperature up to 85 °C. The solubility of Lewis acid in alcohol facilitates nondestructive solution processing on top of polymer, which boosts hole injection from polymer into metal by two orders of magnitude. By integrating the polymer-acid-metal structure into solar cells, devices exhibit remarkable resilience, retaining 96% ± 3%, 96% ± 2% and 75% ± 7% of their initial efficiencies after continuous operation in nitrogen at 35 °C for 2212 h, 55 °C for 1650 h and 85 °C for 937 h, respectively. Leveraging the Arrhenius relation, we project an impressive T80 lifetime of 26,126 h at 30 °C.

Approach to Significantly Enhancing the Electrochromic Performance of PANi by In Situ Electrodeposition of the PANi@MXene Composite Film.

Electrochromic materials (ECMs) are capable of reversibly adjusting their transmittance or reflectance properties in response to changes in the external biasing voltages. In this study, we enhanced the electrochromic and electrochemical properties of polyaniline (PANi) effectively through the incorporation of MXene Ti2CTx using an in situ composite strategy. This improvement in the electrochromic and electrochemical properties observed can be attributed to the intermolecular forces between the aniline group of PANi and the terminal groups of MXene Ti2CTx sheets. The presence of hydrogen bonds between the PANi monomers and the MXene sheets was confirmed through theoretical calculations and photoluminescence results, which effectively improved the composite interfaces. Additionally, the PANi@MXene composite films were successfully prepared through a simple one-step in situ polymerization process, as verified by SEM and XPS characterization. The electrochemical studies revealed enhanced electronic conductivity, a high ion diffusion coefficient, and a narrow energy redox gap, all contributing to the excellent electrochemical properties observed. Overall, our results demonstrate that the MXene Ti2CTx composition effectively enhances the electrochromic performance of PANi. The PANi@MXene composite films exhibited a high optical modulation range, rapid switching response time, good thermal radiation regulation, and excellent operational stability. This composite strategy significantly improves the performance and practical applicability of ECMs.

Trace Doping: Fluorine-Containing Hydrophobic Lewis Acid Enables Stable Perovskite Solar Cells.

With the rapid development in perovskite solar cell (PSC), high efficiency has been achieved, but the long-term operational stability is still the most important challenges for the commercialization of this emerging photovoltaic technology. So far, bi-dopants lithium bis(trifluoromethylsulfonyl)-imide (Li-TFSI)/4-tert-butylpyridine (t-BP)-doped hole-transporting materials (HTM) have led to state-of-the art efficiency in PSCs. However, such dopants have several drawbacks in terms of stability, including the complex oxidation process, undesirable ion migration and ultra-hygroscopic nature. Herein, a fluorine-containing organic Lewis acid dopant bis(pentafluorophenyl)zinc (Zn-FP) with hydrophobic property and high migration barrier has been employed as a potential alternative to widely employed bi-dopants Li-TFSI/t-BP for poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). The resulting Zn-FP-based PSCs achieve a maximum PCE of 20.34 % with hysteresis-free current density-voltage (J-V) scans. Specifically, the unencapsulated device exhibits a significantly advanced of operational stability under the International Summit on Organic Photovoltaic Stability protocols (ISOS-L-1), maintaining over 90 % of the original efficiency after operation for 1000 h under continuous 1-sun equivalent illumination in N2 atmosphere in both forward and reverse J-V scan.

CT evaluation of upper thoracic spine for surgical application of transarticular screw placement.

INTRODUCTION: Although pedicle screw fixation has been increasingly used in the upper thoracic spine in recent years, controversies exist about the safety and complications such as nerve or vascular intrusion associated with the technique. In this study, an alternative method of transarticular screw fixation was validated. MATERIALS AND METHODS: Morphometric analysis was performed on computed tomography (CT) scans of the upper thoracic zygapophysial joints of C7, T1, T2 and T3 in 20 male and 20 female patients in the axial and sagittal planes. The degree of screw angulation was recorded in the sagittal and axial planes and the screw length was measured at the spinal level from C7 to T3. RESULTS: The smallest medial-lateral diameter and anterior-posterior diameter of IAP was found at T3 in the female patients and C7 in the male patients. The screw trajectory length ranged from 14.9 to 20.5 mm in all patients. All the above measurements were significantly different between male and female patients at all levels (P < 0.05). The mean value of screw trajectory angle was 19.3°-20.1° in the axial plane and 44.3°-45.7° in the sagittal plane. There was no statistically significant difference (P > 0.05) between male and female patients in the axial and sagittal angles. CONCLUSION: The morphometric data of C7-T3 zygapophysial joints indicate the suitable screw diameter and screw length for this technique. Transarticular screw fixation proved to be a potentially safe alternative to pedicle screw fixation in this region.

A new strategy for constructing a dispiro-based dopant-free hole-transporting material: spatial configuration of spiro-bifluorene changes from a perpendicular to parallel arrangement.

Due to the low intrinsic hole mobility caused by the orthogonal conformation of two fluorene units in Spiro-OMeTAD which is a classic hole-transporting material (HTM) in perovskite solar cells (PSCs), Spiro-OMeTAD based PSCs generally can only obtain high performances through a sophisticated doping process with dopants/additives, which adds to the cost and complicacy of device fabrication, and also adversely affects the stability of PSC devices. Herein, a novel dispiro-based HTM, WH-1, is designed by cleverly replacing the central carbon atom of Spiro-OMeTAD with cyclohexane, and the spatial configuration of the HTM is changed from vertical orthogonality of the two fluorene units to a parallel arrangement, which is beneficial for the formation of a homogeneous and compact HTM film on the surface of the perovskite film, improvement of intermolecular electronic coupling and intrinsic hole mobility. WH-1 is obtained by two-step facile synthesis with a high yield from commercially available materials. WH-1 is used in PSCs as a dopant-free HTM, which is the first time that the dispiro-based molecule has been applied as a dopant-free HTM, and a power conversion efficiency (PCE) of 19.57% is obtained, rivaling Li-TFSI/t-BP doped Spiro-OMeTAD in PCE (20.29%), and showing obvious superior long-term stability.