Efficient lead (Pb)‐free inverted planar formamidinium tin triiodide (FASnI3) perovskite solar cells (PVSCs) are demonstrated. Our FASnI3 PVSCs achieved average power conversion efficiencies (PCEs) ...of 5.41% ± 0.46% and a maximum PCE of 6.22% under forward voltage scan. The PVSCs exhibit small photocurrent–voltage hysteresis and high reproducibility. The champion cell shows a steady‐state efficiency of ≈6.00% for over 100 s.
Good mechanical properties and large adiabatic temperature change render Heusler-type Ni2FeGa-based magnetic shape memory alloys as a promising candidate material for solid-state mechanical cooling ...application at ambient conditions. Superelastic behavior and associated elastocaloric effect strongly reply on deformation conditions (e.g. applied strain rate and strain level) of stress-induced martensitic transformations. With the aim of developing high-performance elastic cooling materials, in this work, we have carried out a systematic study on a Ni54Fe19Ga27 420-oriented single crystal by exploring the interaction between dynamic deformation parameters and thermal response. A giant and reversible adiabatic temperature change of ±7.5 K triggered by a low stress of 30 MPa was achieved. Such a high specific cooling performance thus offers the great advantage for the small scale solid-state mechanical cooling applications. Besides, a significant temporary residual strain effect has been observed at high strain rate, which is unfavorable for reversible elastocaloric effect but can be overcome by reducing stress hysteresis, and/or by elevating initial environmental temperature. The established criterion for the desirable reversible elastocaloric properties goes beyond the present system, and can be applicable for other shape memory alloys used for elastic cooling techniques.
Light‐emitting diodes (LEDs) in a tandem configuration offer a strategy to realize high‐performance, multicolor devices. Until now, though, the efficiency of tandem colloidal quantum dot LEDs (QLEDs) ...has been limited due to unpassivated interfaces and solvent damage originating from the materials processing requirements of interconnecting layers (ICLs). Here an ICL is reported consisting of a semiconductor‐metal‐dielectric stack that provides facile fabrication, materials stability, and good optoelectronic coupling. It is investigated experimentally how the ICL enables charge balance, suppresses current leakage, and prevents solvent damage to the underlying layers. As a result record efficiencies are reported for double‐junction tandem QLEDs, whose emission wavelengths cover from blue to red light; i.e., external quantum efficiencies (EQEs) of 40% (average 37+/−2%) for red, 49% (average 45+/−2%) for yellow, 50% (average 46+/−2%) for green, and 24% (average 21+/−2%) for blue are achieved.
A highly efficient interconnecting layers (ICLs) are reported consisting of multifunctional inorganic semiconductor‐metal‐dielectric stack, which enables the resultant tandem quantum dot light emitting diodes (QLEDs) with double junction to achieve a record efficiency, with the EQEs of 40% for red, 49% for yellow, 50% for green, and 24% for blue.
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As one of the most promising medical metal implants, magnesium (Mg) or its alloys have shown significant advantages over other candidates attributed to not only their excellent ...biodegradability and suitable mechanical properties but also their osteopromotive effects for bone applications. Prior to approval mandated by the governmental regulatory body, the access to the medical market for Mg-based implants requires a series of testing for assurance of their safety and efficacy via preclinical evaluations and clinical tests including phase 1 and 2 evaluations, and phase 3 of multi-center randomized double blind and placebo-controlled clinical trials. However, as the most widely used protocols for biosafety evaluation of medical devices, current ISO 10993 standards should be carefully reevaluated when directly applying them to predict potential health risks of degradable Mg based biomaterials via cytotoxicity tests due to the huge gap between in vitro and in vivo conditions. Therefore, instead of a direct adoption, modification of current ISO standards for in vitro cytotoxicity test is desirable and justified. The differences in sensitivities of cells to in vitro and in vivo Mg ions and the capability of in vivo circulation system to dilute local degradation products were fully considered to propose modification of current ISO standards. This paper recommended a minimal 6 times to a maximal 10 times dilution of extracts for in vitro cytotoxicity test specified in ISO 10993 part 5 for pure Mg developed as potential orthopedic implants based on literature review and our specifically designed in vitro and in vivo tests presented in the study. Our work may contribute to the progress of biodegradable metals involved translational work.
Low‐bandgap mixed tin–lead perovskite solar cells (PSCs) have been attracting increasing interest due to their appropriate bandgaps and promising application to build efficient all‐perovskite tandem ...cells, an effective way to break the Shockley–Queisser limit of single‐junction cells. Tin fluoride (SnF2) has been widely used as a basis along with various strategies to improve the optoelectronic properties of low‐bandgap SnPb perovskites and efficient cells. However, fully understanding the roles of SnF2 in both films and devices is still lacking and fundamentally desired. Here, the functions of SnF2 in both low‐bandgap (FASnI3)0.6(MAPbI3)0.4 perovskite films and efficient devices are unveiled. SnF2 regulates the growth mode of low‐bandgap SnPb perovskite films, leading to highly oriented topological growth and improved crystallinity. Meanwhile, SnF2 prevents the oxidation of Sn2+ to Sn4+ and reduces Sn vacancies, leading to reduced background hole density and defects, and improved carrier lifetime, thus largely decreasing nonradiative recombination. Additionally, the F− ion preferentially accumulates at hole transport layer/perovskite interface with high SnF2 content, leading to more defects. This work provides in‐depth insights into the roles of SnF2 additives in low‐bandgap SnPb films and devices, assisting in further investigations into multiple additives and approaches to obtain efficient low‐bandgap PSCs.
In‐depth insights into the roles of tin fluoride (SnF2) additive in low‐bandgap mixed tin (Sn)‐lead (Pb) perovskite and efficient solar cells are provided. The growth mode of the film, highly oriented topological growth, and reduced Sn2+ oxidation are achieved via proper SnF2 doping. Additionally, the accumulation of F− at hole transport layer/perovskite interface is shown at higher SnF2 content, leading to more defects.
Lead thiocyanate in the perovskite precursor can increase the grain size of a perovskite thin film and reduce the conductivity of the grain boundaries, leading to perovskite solar cells with reduced ...hysteresis and enhanced fill factor. A planar perovskite solar cell with grain boundary and interface passivation achieves a steady‐state efficiency of 18.42%.
The unsatisfactory performance of low‐bandgap mixed tin (Sn)–lead (Pb) halide perovskite subcells has been one of the major obstacles hindering the progress of the power conversion efficiencies ...(PCEs) of all‐perovskite tandem solar cells. By analyzing dark‐current density and distribution, it is identified that charge recombination at grain boundaries is a key factor limiting the performance of low‐bandgap mixed Sn–Pb halide perovskite subcells. It is further found that bromine (Br) incorporation can effectively passivate grain boundaries and lower the dark current density by two–three orders of magnitude. By optimizing the Br concentration, low‐bandgap (1.272 eV) mixed Sn–Pb halide perovskite solar cells are fabricated with open‐circuit voltage deficits as low as 0.384 V and fill factors as high as 75%. The best‐performing device demonstrates a PCE of >19%. The results suggest an important direction for improving the performance of low‐bandgap mixed Sn–Pb halide perovskite solar cells.
Charge recombination at grain boundaries is a key factor limiting the performance of low‐bandgap mixed tin–lead halide perovskite solar cells. It is found that bromine incorporation can passivate grain boundaries and lower the dark current density by two to three orders of magnitude. The champion cell shows an open‐circuit voltage deficit of 0.384 V and power conversion efficiency exceeding 19%.
An ultrathin, smooth, and low‐loss Ag film without a wetting layer is achieved by co‐depositing a small amount of Al into Ag. The film can be as thin as 6 nm, with a roughness below 1 nm and ...excellent mechanical flexibility. Organic photovoltaics that use these thin films as transparent electrode show superior efficiency to their indium tin oxide (ITO) counterparts because of improved photon management.
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•Cepharanthine inhibits microglia activation in tMCAO-induced brain.•Cepharanthine inhibits NLRP3 inflammasome-induced inflammation.•Cepharanthine decreases M1 microglia-regulated ...IL-1β and IL-18 production.•Cepharanthine reduces cerebral I/R-induced oxidative stress.•Cepharanthine suppresses cerebral I/R-induced 12/15-LOX signaling.
Cepharanthine (CEP) is a potential candidate for treatment of cerebral ischemia/reperfusion (I/R) injury, due to its anti-inflammatory and anti-oxidative properties. To investigate the effect of CEP on cerebral I/R injury, we established a mouse model of transient middle cerebral artery occlusion (tMCAO) and a microglia cell model of oxygen and glucose deprivation/reoxygenation (OGD/R). Administration of CEP attenuated neurological deficits, reduced infarct volume and edema, and decreased microglia activation in MCAO mice. Immunofluorescence staining showed an up-regulation in NLR Family Pyrin Domain Containing 3 (NLRP3) immunoreactivity in Iba1-labled microglia together with total Iba1 and NLRP3 expression in the brain following tMCAO, while down-regulated by CEP treatment. In both tMCAO-induced mice and OGD/R-treated BV-2 cells, CEP exhibited dose-dependent inhibition on the expression of NLRP3, ASC and cleaved caspase-1. Importantly, CEP attenuated tMCAO or OGD/R-induced overproduction of M1 microglia-regulated pro-inflammation cytokines IL-1β and IL-18, suggesting that CEP might involve in suppressing microglia polarization to M1 phenotype in vivo and in vitro. Moreover, CEP dose-dependently inhibited tMCAO-induced arachidonate 15 lipoxygenase (ALOX15) together with Iba1-labled microglia. The subsequent ALOX15-mediated oxidative stress was decreased by CEP treatment in vivo and in vitro, as evidenced by reduced ROS generation and MDA level, and increased SOD activity. Taken together, we demonstrate that CEP attenuates cerebral I/R injury probably by inhibiting microglia activation and NLRP3 inflammasome-induced inflammation and reducing oxidative stress via suppressing 12/15-LOX signaling.
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