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All-inorganic halide perovskite CsPbX

An all-inorganic CsPbI3 perovskite has exhibited some special excellent properties particularly high thermal stability and potential for tandem solar cells, yet its poor humidity stability and grai...

All-inorganic CsPbI3-x Br x perovskites with appropriate band gap is an attractive semiconductor material for solar applications, whereas their phase stability plays a key role in high-efficiency perovskite solar cells (PSCs). Their device performance was severely constrained by defects, here we found that the promising phenylpropylamine bromide (PPABr) as a simple additive can effectively influence the crystallization kinetics and produce a bifunctional treatment of perovskite, Br ion doping, and organic cation surface passivation. The PPABr treatment has essentially little influence on the light absorption capacity of CsPbI3-x Br x , the band gap is somewhat widened, and the surface hydrophobicity and phase stability are enhanced. CsPbI3-x Br x perovskites treated with PPABr have altered interfacial properties and obtained better interfacial contact, resulting in improved charge extraction and decreased charge recombination. Furthermore, 2.5 mol% PPABr treated CsPbI3-x Br x -based PSCs exhibited repeatable photovoltaic performance with a maximum efficiency of 13.14%. Within 150 h under air circumstances, the PCE attenuation is controlled to within 5% during the test. Hence, passivating inorganic perovskite using organic bromides PPABr is a novel and promising strategy for developing stable, high-performance solar cells.

All-inorganic halide perovskite CsPbX3(X = Br/Cl/I)quantum dots have gained a considerable attention in the optoelectronic fields. However, the high cost and poor stability of the prepared CsPbX3 quantum dots (QDs) are inevitable challenges for their future practical applications. And the high-performance CsPbX3 QDs are always needed. Herein, a facile and low-cost synthesis scheme was adopted to prepare the CsPbBr3 QDs modified by lead bromide (PbBr2) and tetraoctylammonium bromide (TOAB) ligands at room temperature in open air. The prepared CsPbBr3 QDs exhibited a high photoluminescence quantum yield (PLQY) of 96.6% and a low amplified spontaneous emission (ASE) threshold of 12.6 µJ/cm2. Stable ASE intensity with little degradation was also realized from the CsPbBr3 QDs doped with PMMA. Furthermore, the enhanced ASE properties of the CsPbBr3 QDs-doped PMMA based on distributed feedback (DFB) substrate was achieved with a lower threshold of 3.6 µJ/cm2, which is 28.6% of that of the (PbBr2 + TOAB)-treated CsPbBr3 QDs without PMMA. This work exhibits a promising potential in the on-chip light source.

Two-dimensional (2D) perovskite solar cell (PSC) can achieve high stability by alternating interface cations. However, its main transmissive charge is limited owing to the 2D structure. Therefore, compared with a 3D device, the 2D PSC has poor power conversion efficiency (PCE). Further enhanced performance will require an increase in the transmission dimension of 2D PSC. Here, a novel tetraethylenepent (TEPA)-MAPbI3-xClx analogous 2D unsymmetrical perovskite film was developed to improve the stability and PCE of the corresponding device. Based on the interaction of the active amino linear short chain of TEPA and the halogen ion, the symmetry of the mechanical structure of ions is disrupted, and the TEPA ion is embedded in the perovskite structure to form a perovskite structure with a dimension between 3D and 2D. Noticeably, the TEPA-MAPbI3-xClx devices deliver high PCEs up to 19.73% which stands as the highest for MAPbI3-xClx-based PSC. The environmental, thermal, and illumination stability also showed improvements ranging between 10%-30%. The enhanced PSCs are due to the higher quality of perovskite films, stronger charge transmission, and less trap density. This approach provides a new method to improve and modify 2D PSCs.

Inorganic–organic perovskite materials show enormous potential in the aspect of high power conversion efficiency (PCE) due to their superior optoelectronic properties. Herein, we performed a comprehensive analysis of the formamidinium (FA+) influences on the electrical properties and surface morphology of MA1−z FA z Pbl3−x Cl x films, as well as the changes in the perovskite solar cell (PSC) parameter. By adding a suitable amount of FAI to the precursor, a series of PSCs were prepared, with the absorption layer owning a mixed organic cation (MA1−z FA z PbI3−x Cl x ) to passivate interfacial defects and improve stability. This work discovered that the appropriate amounts of FA+ can improve grain size and interference defects generation through interionic interaction. Meanwhile, both the filling factor and the short-circuit current density (J sc) have been enhanced effectively, and the PCE of the champion device is 17.31%. Additionally, the stability of the MA0.6FA0.4PbI3−x Cl x -based PSC is also satisfactory. Under 150 h of darkness at 25 humidity and 25 °C, the PCE fell by just 2.9%. This work reveals that modest FA+ can significantly enhance the film-forming and device performance of MAPbI3−x Cl x by substituting for the A-site cation.

T and B cells continually recirculate between blood and secondary lymphoid organs. To promote their trans‐endothelial migration (TEM), chemokine receptors control the activity of RHO family small GTPases in part via GTPase‐activating proteins (GAPs). T and B cells express several RHO‐GAPs, the function of most of which remains unknown. The ARHGAP45 GAP is predominantly expressed in hematopoietic cells. To define its in vivo function, we describe two mouse models where ARHGAP45 is ablated systemically or selectively in T cells. We combine their analysis with affinity purification coupled to mass spectrometry to determine the ARHGAP45 interactome in T cells and with time‐lapse and reflection interference contrast microscopy to assess the role of ARGHAP45 in T‐cell polarization and motility. We demonstrate that ARHGAP45 regulates naïve T‐cell deformability and motility. Under physiological conditions, ARHGAP45 controls the entry of naïve T and B cells into lymph nodes whereas under competitive repopulation it further regulates hematopoietic progenitor cell engraftment in the bone marrow, and T‐cell progenitor thymus seeding. Therefore, the ARGHAP45 GAP controls multiple key steps in the life of T and B cells., T and B cells continually recirculate between blood and secondary lymphoid organs. The RHO GTPase activating protein ARHGAP45 regulates naïve T cell deformability, motility, and chemotaxis, and thereby regulates key trafficking steps of T and B cells in vivo.

Inorganic lead halide perovskites have a reasonable energy bandgap, which makes them ideal for tandem devices. As a result, inorganic lead halide perovskite solar cells (PSCs) could be prospective next-generation solar materials, but the issue of instability under moisture remains unaddressed. Adding 4-fluoro-phenyl-ethylammonium iodide (F-PEAI) spacer cations to the perovskite precursor solution is an elementary addition method to improve the performance of PSCs. We study the impact of F-PEAI on the perovskite crystal phase and the effect of F-PEAI concentration on PSC performance. F-PEAI was used to passivate interfacial flaws and vacancies in inverted inorganic PSCs and improve moisture tolerance, resulting in a mixed 2D/3D heterostructure. A small number of F-PEAI-treated PSCs have changed interfacial characteristics, resulting in better charge extraction and less charge recombination. The power conversion efficiency (PCE) of the F-PEAI treated device is much higher than that of the control group, and the PCE is improved to more than 11%. To attain high efficiency, all-inorganic perovskites can be modified using a straightforward method.

Regulatory B cells (Bregs) are a functionally defined B cell subset, and IL-10 is crucial for the suppressive functions of Bregs. However, little is known regarding how IL-10 production is regulated in B cells. To explore the mechanisms by which IL-10 is regulated in B cells, we used mRNA microarrays to screen for molecules that are upregulated in IL-10-producing B cells and identified RNA-binding motif protein 47 (Rbm47) as a post-transcriptional regulator. Rbm47 was found to promote IL-10 production in B cells. We found that Rbm47 promotes the stability of IL-10 mRNA by binding to AU-rich elements in the 3′ untranslated region of Il10 mRNA. In addition, we demonstrated that the overexpression of Rbm47 enabled B cells to facilitate Foxp3+ regulator T-cell induction and reduce the severity of DSS-induced ulcerative colitis. Taken together, these results suggest that Rbm47 plays an important role in regulating IL-10 at the post-transcriptional level, thus promoting the regulatory functions of B cells. The findings presented in this study not only increase our understanding of the post-translational regulation of IL-10 in B cells but also identify a novel strategy for the potential application of Bregs.

The inverted bottom-emitting organic light-emitting devices (IBOLEDs) were prepared, with the structure of ITO/Al (x nm)/LiF (1 nm)/Bphen (40 nm)/CBP: GIr1 (14%):R-4b (2%) (10 nm)/BCP (3 nm)/CBP:GIr1 (14%):R-4b (2%) (20 nm)/TCTA (10 nm)/NPB (40 nm)/MoO3 (40 nm)/Al (100 nm), where the thickness of electron injection layer Al (x) are 0 nm, 2 nm, 3 nm, 4 nm and 5 nm, respectively. In this paper, the electron injection condition and luminance properties of inverted devices were investigated by changing the thickness of Al layer in Al/LiF compound thin film. It turns out that the introduction of Al layer can improve electron injection of the devices dramatically. Furthermore, the device exerts lower driving voltage and higher current efficiency when the thickness of electron injection Al layer is 3 nm. For example, the current efficiency of the device with 3-nm-thick Al layer reaches 19.75 cd·A-1 when driving voltage is 7 V, which is 1.24, 1.17 and 17.03 times larger than those of the devices with 2 nm, 4 nm and 5 nm Al layer, respectively. The device property reaches up to the level of corresponding conventional device. In addition, all inverted devices with electron injection Al layer show superior stability of color coordinate due to the adoption of co-evaporation emitting layer and BCP spacer-layer, and the color coordinate of the inverted device with 3-nm-thick Al layer only changes from (0.580 6, 0.405 6) to (0.532 8, 0.436 3) when driving voltage increases from 6 V to 10 V.

The immune balance of the respiratory tract is strictly regulated. Extracellular vesicles (EVs) have been reported to participate in maintaining the immune balance in the intestinal tract, but whether they are involved in regulation of the immune balance in the respiratory tract has yet to be revealed. In this study, we found that physiological EVs from lungs of WT mice (L-EVs) could be isolated, which contained the immunosuppressive cytokines TGF-β1 and IL-10. Among L-EV subsets, only the CD8α+CD11c+ EV subset was positive for TGF-β1 and IL-10 and could inhibit CD4+ T cell proliferation via TGF-β1 in vitro and relieve murine asthmatic symptoms. Mechanistically, L-EVs were effective at inhibiting OVA peptide–specific CD4+ T cell proliferation in a TGF-β1– and IL-10–dependent manner. In addition, they could prevent CD4+ T cells from hilar lymph nodes from secreting IL-4, IL-9, and IL-17A via IL-10 ex vivo, suggesting inhibition of Th2, Th9, and Th17 cell responses. Altogether, our results indicate that EVs from the lungs are involved in control of the immune balance in the respiratory tract, which reveals a novel mechanism in the maintenance of respiratory tract immune homeostasis.

The photoelectric properties of LED are affected by driving current and ambient temperature. To solve the problem of light wane caused by excessive current and overheating, LLC resonant converter with soft switching was chosen as the main topology, improving the power efficiency, and reducing the heat of the LED driver. Firstly, the soft-switching conditions of the LLC resonant converter are analyzed, and the constraint equation is obtained. Then, an improved particle swarm optimization algorithm is proposed to optimize the resonant parameters. The weight of particles is dynamically and adaptively changed to balance the global and local optimization performance of particles. Finally, the controller is designed to realize constant current. This design improves the efficiency of the LED driver. At the same time, the light wane is effectively suppressed by stable output current, and the rationality of the selected parameters is verified by simulation and experiment.

Double-emitting layer inverted organic light-emitting devices (IOLEDs) with different spacer layers were investigated, where 2,20,7,70-tetrakis(carbazol-9-yl)-9,9-spirobifluorene (CBP), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen) and 4,40,400-tris(N-carbazolyl)-triphenylamine (TCTA) were used as spacer layers, respectively, and GIr1 and R-4b were used as green and red guest phosphorescent materials, respectively. The results show that the device with BCP spacer layer has the best performance. The maximum current efficiency of the BCP spacer layer device reaches up to 24.15 cd·A-1 when the current density is 3.99 mA·cm-2, which is 1.23 times bigger than that of the CBP spacer layer device. The performance is better than that of corresponding conventional device observably. The color coordinate of the device with BCP spacer layer only changes from (0.625 1, 0.368 0) to (0.599 5, 0.392 8) when the driving voltage increases from 6 V to 10 V, so it shows good stability in color coordinate, which is due to the adoption of the co-doping evaporation method for cladding luminous layer and the effective restriction of spacer layer to carriers in emitting layer.

Transparent organic light-emitting devices (TOLEDs) based on a stacked alloy cathode of LiF/Al:Ag are investigated. The devices have a structure of indium-tin-oxide (ITO)/4,4′,4″-Tris[2-naphthyl(phenyl)amino]triphenylamine (2T-NATA) (25 nm)/N,N′-Di-[(1-naphthyl)-N,N′-diphenyl]-1,1’-biphenyl-4,4′-diamine (NPB) (40 nm)/tris-(8-hydroxyquinoline) aluminum (Alq3) (50 nm)/LiF (1 nm)/Al:Ag (1:3) (x), where the thicknesses of cathode metal layers (Al:Ag) are adjusted, respectively, from 70 nm to 100 nm. In the experiment, it is found that the LiF (1 nm)/Al:Ag (1:3) (75 nm) has good electron injection efficiency. Compared with an Al-only cathode, the turn-on voltage is lowered. At the voltage of 10 V, the luminances for bottom emission from ITO anode side and top emission from metal cathode side are 2 459 cd/m2 and 1 729 cd/m2, respectively. Thanks to electron injection enhancement by using Al:Ag cathode, we can obtain a better energy level matching between the cathode and the organic layer, thus the devices have lower turn-on voltage and higher luminance. The total transmittance of the devices can achieve about 40% at the wavelength of 550 nm.

Two-dimensional (2D) perovskite solar cell (PSC) can achieve high stability by alternating interface cations. However, its main transmissive charge is limited owing to the 2D structure. Therefore, compared with a 3D device, the 2D PSC has poor power conversion efficiency (PCE). Further enhanced performance will require an increase in the transmission dimension of 2D PSC. Here, a novel tetraethylenepent (TEPA)-MAPbI

With the gradually development of deep learning, the object detection algorithm has achieved remarkable applications, especially in the aspect of the automatic driving. Most of the object detection algorithms are used for pictures or videos obtained by a general camera. In practice, fisheye cameras are widely used, which will produce distorted image frames. The research of vehicle detection based on fisheye camera is relatively rare until now. If one network is trained on the existed public dataset, and tested on the distorted images or videos, the accuracy will decrease a lot. Thus, a distorted vehicle dataset needs to be manually labeled in the first. However, if we only use the distorted vehicle dataset to train the model, the mount of the distorted vehicle dataset is small, meanwhile the public datasets will not be fully used. On the other hand, the missing detection and false detection for the distorted images by using SSD algorithm is a considerable problem. Based on those considerations, firstly, transfer learning is adopted to transfer the parameters learned from the public vehicle dataset to the distorted vehicle dataset in this paper. Secondly, an algorithm named MLSSD for the distorted vehicle detection based on the labeled dataset is proposed to achieve a better performance for the vehicle detection, which mainly combines metric learning and SSD algorithm to enormously alleviate the missing detection and false detection. In addition, the scalable overlapping partition pooling (SOPP) method is proposed instead of the spatial pyramid pooling to achieve more robust feature map pooling. Experimental results show that the proposed MLSSD algorithm significantly outperforms other algorithms and achieves 88.3 % mAP on the distorted vehicle dataset, 3.1% more than the result obtained by the SSD network.