Crystallization control of wide-bandgap perovskites for efficient solar cells via adding an anti-solvent into the perovskite precursor.

Organic-inorganic halide-based wide-bandgap perovskite solar cells (PSCs) have been researched extensively due to their potential application in tandem solar cells. In this study, we directly added an anti-solvent (diethyl ether, DE) into the perovskite precursor for controlling the crystallization process of perovskite layers with a wide bandgap (1.74 eV). The introduction of DE could facilitate the nucleation and accelerate the perovskite growth during the spin-coating process. Due to the improved crystallization of the perovskite, the wide-bandgap PSCs showed a high power-conversion efficiency (PCE) of 19.7% on average with improved current density and fill factor. In contrast, the control devices without using DE exhibited a low average PCE of 17.6%. Moreover, the ambient stability of the related PSCs was simultaneously enhanced with a remarkably decreased PCE degradation, from 31.3% to 16.8%, after 16 days of storage and measurement. The DE-assisted well-crystallized PSCs showed a highest PCE of 20.1%, with a stable current output and negligible hysteresis. Our research provides a simple and effective way for controlling the crystallization of wide-bandgap perovskite layers and hence improving the performance of wide-bandgap PSCs.

A Comparative Study of Nafion 212 and Sulfonated Poly(Ether Ether Ketone) Membranes with Different Degrees of Sulfonation on the Performance of Iron-Chromium Redox Flow Battery.

For an iron-chromium redox flow battery (ICRFB), sulfonated poly(ether ether ketone) (SPEEK) membranes with five various degrees of sulfonation (DSs) are studied. To select the SPEEK membrane with the ideal DS for ICRFB applications, the physicochemical characteristics and single-cell performance are taken into consideration. Following all the investigations, it has been determined that the SPEEK membrane, which has a DS of 57% and a thin thickness of 25 µm, is the best option for replacing commercial Nafion 212 in ICRFB. Firstly, it exhibits a better cell performance according to energy efficiency (EE) and coulombic efficiency (CE) at the current density range between 40 mA cm-2 and 80 mA cm-2. Additionally, it has a more stable EE (79.25-81.64%) and lower discharge capacity decay rate (50%) than the Nafion 212 (EE: 76.74-81.45%, discharge capacity decay: 76%) after 50 charge-discharge cycles, which proves its better oxidation stability as well. In addition, the longer self-discharge time during the open-circuit voltage test further demonstrates that this SPEEK membrane could be employed for large-scale ICRFB applications.

Improving the performance of ternary organic solar cells using metal oxides as charge-transport layers.

In this study, we improved the performance of ternary organic solar cells (OSCs) using metal oxides (p-type NiOx and n-type SnO2) as the charge-transport layers (CTLs). The use of NiOx and SnO2 can facilitate charge transportation and suppress charge recombination in PM6:IDIC:Y6-based ternary OSCs, which is beneficial for boosting their performance. As a result, the OSCs with CTLs of NiOx and SnO2 exhibited an improved power conversion efficiency (PCE) of 16.2% (on average), which is higher than that (15.1%) of the control OSCs using poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) and LiF as the CTLs. The stability of the OSCs was simultaneously improved with the PCE degradation significantly suppressed upon using NiOx and SnO2. After 10 days of storage and measurement under ambient conditions, the PCE degradation was dramatically decreased from 49.7% to 20.3%, which was induced by the high intrinsic stability of NiOx and SnO2. The best OSC using the CTLs of NiOx and SnO2 showed a champion PCE of 16.6%, with a stable power output and negligible hysteresis.

Multidiscipline Applications of Triboelectric Nanogenerators for the Intelligent Era of Internet of Things.

In the era of 5G and the Internet of things (IoTs), various human-computer interaction systems based on the integration of triboelectric nanogenerators (TENGs) and IoTs technologies demonstrate the feasibility of sustainable and self-powered functional systems. The rapid development of intelligent applications of IoTs based on TENGs mainly relies on supplying the harvested mechanical energy from surroundings and implementing active sensing, which have greatly changed the way of human production and daily life. This review mainly introduced the TENG applications in multidiscipline scenarios of IoTs, including smart agriculture, smart industry, smart city, emergency monitoring, and machine learning-assisted artificial intelligence applications. The challenges and future research directions of TENG toward IoTs have also been proposed. The extensive developments and applications of TENG will push forward the IoTs into an energy autonomy fashion.

High-performance Ruddlesden-Popper two-dimensional perovskite solar cells via solution processed inorganic charge transport layers.

Two-dimensional (2D) layered halide perovskites have been shown to enable improved long-term stability in comparison to the well-known three-dimensional hybrid organic-inorganic halide perovskites. The optoelectronic properties of the 2D perovskites are strongly influenced by the chemical nature of the charge transport layer. In this work, we fabricated Ruddlesden-Popper 2D perovskite solar cells (PSCs) using solution processed inorganic NiOx and a C60 : C70 (1 : 1) mixture as the hole and electron transport layers, which significantly improved the performance of the 2D PSCs. Time resolved photoluminescence measurements indicate the shortened lifetime of excitons, which demonstrates the excellent charge extraction properties. The PSCs based on these inorganic charge transport materials (CTMs) exhibit an average power conversion efficiency (PCE) of 14.1%, which is higher than that (12.3%) of PSCs using organic CTMs of poly(3,4-ethylenedioxythiophene) : poly(styrenesulfonate) (PEDOT:PSS) and phenyl-C61-butyric acid methyl ester (PCBM). Compared with PEDOT:PSS and PCBM based cases, the PSCs using inorganic CTMs also show improved long-term stability, with the PCE degradation significantly suppressed from 20% to 12% after a measurement of 15 days. The best PSCs using NiOx and C60 : C70 show a high PCE of 14.4%, with a stable power output and negligible hysteresis.

[Acupoint sensitization enhances inhibitory effect of electroacupuncture on jejunum mobility in rats].

OBJECTIVE: To observe the effect difference of electroacupuncture (EA) at the sensitized and non-sensitized acupoint "Tianshu" (ST25) on the motility of jejunum in rats. METHODS: Male SD rats were randomly divided into blank control, sensitized ST25 (sensitization), and non-sensitized ST25 (non-sensitization) groups (n=16 in each group). The sensitization and non-sensitization were induced by injection of 15% mustard oil (20 µL) and Paraffin oil (20 µL) into the left ST25 area respectively. The rats' behavior reactions were assessed by recording the numbers and duration of licking the local sensitized skin region. At the end of experiments and after regular trans-cardiac perfusion and fixing with 10% neutral formaldehyde, the skin and muscular tissues of the ST25 region (1 cm×1 cm) were taken for H.E. staining to observe the local histopathologic changes. The intestinal motility was detected by recording the contraction pressure waves of jejunum through a small balloon-connected pressure transducer and an amplifier, followed by calculating the ratios of amplitude and frequency of contraction waves between pre- and post-EA stimulation. EA (2 Hz, 0.2-6.0 mA) was applied to the sensitized and non-sensitized ST25 regions for 20 s for comparing their effects on jejunum motility. RESULTS: Compared with the blank control group, mustard oil injection but not Paraffin oil injection resulted in histological edema and neutrophils infiltration in tissues of ST25 region, and also striking increase of the number and duration of licking (P<0.01), suggesting a sensitization of ST25 area after mustard oil injection. The ratios of spontaneous contraction amplitude and frequency of jejunum were remarkably decreased in mustard oil-treated rats compared to baseline and Paraffin oil group (P<0.001，P<0.01). The maximum inhibitory effect of EA on the intestinal movement amplitude was significantly higher in the sensitization group than in the blank control and non-sensitization groups (P<0.05，P<0.01), and there was a dose-effect relationship between the current intensity of EA (0.5-3.0 mA) and the inhibitory rate 50% of the contraction amplitude (not the frequency) in the sensitization group (P<0.001), but not in the blank control and non-sensitization groups (P>0.05). Additionally, 1.5 mA EA stimulation at the sensitized ST25 (not at the non-sensitized ST25) had an inhibitory effect on the contraction amplitude (P<0.05) rather than on the contraction frequency (P>0.05) in comparison with the blank control group. CONCLUSION: Sensitization of acupoint ST25 can modulate the motility of jejunum and enhances the inhibitory effect of EA on the contraction amplitude of jejunum in rats. The inhibitory effect of sensitized ST25 EA is evidently stronger than that of the non-sensitized ST25 EA.

Alcohol based vapor annealing of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) layer for performance improvement of inverted perovskite solar cells.

In this study, we introduced alcohol based vapor annealing of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer for fabricating high-performance inverted perovskite solar cells. Atomic force microscopy measurements and atomistic theoretical simulations indicated that phase separation between PEDOT and PSS was enhanced by this annealing, improving the hole conductivity at the PEDOT:PSS layer. As a result of using methanol, the short-circuit current density improved from 20.7 to 21.6 mA cm-2; consequently, the power conversion efficiency (PCE) improved from 16.1 to 17.3%. However, using ethanol or isopropanol yielded a smaller performance improvement. The PCEs of the best sample in this study under forward and reverse scans were 17.7 and 18.0%, respectively, indicating that the PSC had a small hysteresis. Our results suggest that alcohol vapor annealing is a simple and effective method of developing high-performance inverted perovskite solar cells.

Performance Regulation of Thieno[3,2-b]benzothiophene π-Spacer-Based D-π-A Organic Dyes for Dye-Sensitized Solar Cell Applications: Insights From Computational Study.

Dye-sensitized solar cells (DSSCs) have been widely investigated; however, the development of promising dye sensitizers is still appealing. In this work, we perform a detailed theoretical search for high-efficiency D-π-A organic dyes using density functional theory and time-dependent density functional theory calculations. Specifically, we perform geometric optimization, and electronic structure and absorption spectra calculations for isolated dyes for two thieno[3,2-b]benzothiophene π-spacer-based D-π-A organic dyes SGT129 and SGT130, which show significant efficiency difference, before and after binding to a TiO2 semiconductor. The calculation results reveal that the coplanar configuration between the electron donor and the π-spacer can enhance electronic communication efficiently, thus facilitating intra-molecular charge transfer from the electron donor to the acceptor groups in SGT130. The absorption spectrum of SGT130 broadens and is red-shifted owing to the decreased bandgap. The higher light-harvesting efficiency, favorable intra-molecular charge transfer, larger shift of the conduction band edge in the TiO2 semiconductor, and slower charge recombination between the injected electrons in the TiO2 conduction band and the electrolyte explain the superior efficiency of SGT130 over that of SGT129. Using SGT130 as the reference dye, we further design four novel dyes 1-4 by modifying the π-spacer with electron-rich and electron-withdrawing moieties. Judging from the theoretical parameters influencing the short-circuit current and open-circuit voltage, we found that all dyes would perform better than SGT130 in terms of the favorable interfacial charge transfer (ICT) and light-harvesting efficiency, as well as the larger shift of the TiO2 conduction band edge. Our theoretical research is expected to provide valuable insights into the molecular modification of TBT-based D-π-A organic dyes for DSSC applications.

Prognostic significance of the neutrophil-to-lymphocyte ratio in primary liver cancer: a meta-analysis.

The neutrophil-to-lymphocyte ratio (NLR) is a useful biomarker that reflects systemic inflammation responses. However, the prognostic value of the NLR in patients with primary liver cancer (PLC) remains controversial. We performed a meta-analysis of 26 studies (comprising 4,461 patients) to evaluate the association between the pre-treatment NLR and clinical outcomes of overall survival (OS) and disease-free survival (DFS) in patients with PLC. The correlation between NLR and tumor characteristics or other inflammation-related parameters was also assessed. Data were synthesized using the random-effects model of DerSimonian and Laird, and the hazard ratio (HR) or odds ratio (OR) with 95% confidence interval (CI) was used to estimate effect size. Our analysis indicated that a high NLR predicted poor OS (HR, 2.102; 95% CI: 1.741-2.538) and DFS (HR, 2.474; 95% CI: 1.855-3.300) for PLC. A high NLR was associated with the presence of tumor vascular invasion (OR: 1.889, 95% CI: 1.487-2.400; p<0.001) and an elevated alpha-fetoprotein level (OR: 1.536; 95% CI: 1.152-2.048; p = 0.003). Thus, we conclude that a high NLR indicates a poor prognosis for patients with PLC and may also be predictive for PLC invasion and metastasis. Subgroup analysis suggested that the predictive role of NLR in cholangiocarcinoma is limited, and a further large study to confirm these findings is warranted.