Perovskite solar cells (PSCs) have achieved certified power conversion efficiency (PCE) over 25%. Though their high PCE can be achieved by optimizing absorber layer and device interfaces, the ...intrinsic instability of perovskite materials is still a key issue to be resolved. Mixed‐halide perovskites using multiple halogen constituents have been proved to improve robustness; however, the anion at the X site in the ABX3 formula is not limited to halogens. Other negative monovalent ions with similar properties to halogens, such as pseudo‐halogens, have the opportunity to form perovskites with ABX3 stoichiometry. Recently, thiocyanates and formates have been utilized to synthesize stable perovskite materials. This review presents the evolution of pseudo‐halide perovskite solar cells in the past few years. The intrinsic properties, their effects on crystal structure, and bandgap engineering of the pseudo‐halide perovskites are summarized. Various thiocyanate compounds applied in the fabrication of perovskite solar cells are discussed. The fabrication process, film formation mechanism, and crystallinity of pseudo‐halide perovskites are elucidated to understand their effects on the photovoltaic performance and device stability. Other applications of pseudo‐halide perovskites are summarized in the final section. Lastly, this review concludes with suggestions and outlooks for further research directions.
Monovalent pseudo‐halide anions share similar properties to halide anions. This review presents the evolution of pseudo‐halide perovskite solar cells in the past few years. The role of pseudo‐halides and their position and occupation in perovskite crystal, its impact on perovskite film quality, solar cell stability and photovoltaic performance, and pseudo‐halide optoelectronic devices beyond solar cells are compared comprehensively.
The soft and polar nature of quasi‐2D (PEA)2PbBr4 perovskite, and robust photo‐generated excitons lead exciton‐polaritons and exciton‐polarons as the important phenomena near the band edge for ...application in the lighting aspect. In this work, a convenient methodology is proposed based on the polariton resonant modes in temperature‐dependent (77 K to RT) spectroscopy, and investigate the effect of these quasi‐particles on refractive index dispersion. The large binding energy (≈335 meV) of quasi‐2D excitons is obtained by the reflectance measurements at 77 K. Stable exciton‐polaritons and exciton‐polarons are confirmed by energy dispersions and the observation of self‐trapped exciton‐polaron state, respectively. Furthermore, the large negative thermal‐optic coefficient due to damping effect of exciton‐phonon scattering is observed. The phenomenon is opposite to those observed in conventional semiconductors (e.g., Si, Ge, GaN, AlN, GaAs, AlAs, and ZnO etc.). The observed stable negative thermal‐optic coefficients from 160 K to RT indicate that the quasi‐2D perovskite can be used as a phase compensator for conventional semiconductor materials.
The shrinkage of the energy difference between lower polariton branches (LPs) and upper polariton branches (UPs) proves that oscillator strength decreases when the temperature rises from 77 to 300 K. Therefore, the strong damping effect of exciton‐phonon interactions reduces the oscillator strength when the temperature rises, and further result in the negative thermal‐optic behaviors of quasi‐2D (PEA)2PbBr4 perovskite.
The rapid emergency of data science, information technology, and artificial intelligence (AI) relies on massive data processing with high computing efficiency and low power consumption. However, the ...current von‐Neumann architecture system requires high‐energy budget to process data computing and storage between central computing unit and memory. To overcome this problem, neuromorphic computing system which mimics the operation of human brain has been proposed to perform computing in an energy‐efficient manner. Recently, organic–inorganic halide perovskite compounds have been demonstrated as promising components for neuromorphic devices owing to their strong light absorption, solution processability, and unique properties such as ion migration, carrier trapping effects and phase transition. In this review paper, we report recent advances of neuromorphic devices which employed organic–inorganic halide perovskite compounds by analyzing their fundamental operating mechanisms, device architectures, applications and future prospective.
Neuromorphic devices have been attracted much attention as next generation computing system to process the large amount of data. This review paper reports on neuromorphic devices based on organic–inorganic halide perovskite compounds including fundamental operating mechanisms, device architectures, applications, and future prospective.
An important factor in evaluating health risk of near-road air pollution is to accurately estimate the traffic-related vehicle emission of air pollutants. Inclusion of traffic parameters such as road ...length/area, distance to roads, and traffic volume/intensity into models such as land use regression (LUR) models has improved exposure estimation. To better understand the relationship between vehicle emissions and near-road air pollution, we evaluated three traffic density-based indices: Major-Road Density (MRD), All-Traffic Density (ATD) and Heavy-Traffic Density (HTD) which represent the proportions of major roads, major road with annual average daily traffic (AADT), and major road with commercial annual average daily traffic (CAADT) in a buffered area, respectively. We evaluated the potential of these indices as vehicle emission-specific near-road air pollutant indicators by analyzing their correlation with black carbon (BC), a marker for mobile source air pollutants, using measurement data obtained from the Near-road Exposures and Effects of Urban Air Pollutants Study (NEXUS). The average BC concentrations during a day showed variations consistent with changes in traffic volume which were classified into high, medium, and low for the morning rush hours, the evening rush hours, and the rest of the day, respectively. The average correlation coefficients between BC concentrations and MRD, ATD, and HTD, were 0.26, 0.18, and 0.48, respectively, as compared with -0.31 and 0.25 for two commonly used traffic indicators: nearest distance to a major road and total length of the major road. HTD, which includes only heavy-duty diesel vehicles in its traffic count, gives statistically significant correlation coefficients for all near-road distances (50, 100, 150, 200, 250, and 300 m) that were analyzed. Generalized linear model (GLM) analyses show that season, traffic volume, HTD, and distance from major roads are highly related to BC measurements. Our analyses indicate that traffic density parameters may be more specific indicators of near-road BC concentrations for health risk studies. HTD is the best index for reflecting near-road BC concentrations which are influenced mainly by the emissions of heavy-duty diesel engines.
X-ray detection has widespread applications in medical diagnosis, non-destructive industrial radiography and safety inspection, and especially, medical diagnosis realized by medical X-ray detectors ...is presenting an increasing demand. Perovskite materials are excellent candidates for high-energy radiation detection based on their promising material properties such as excellent carrier transport capability and high effective atomic number. In this review paper, we introduce X-ray detectors using all kinds of halide perovskite materials along with various crystal structures and discuss their device performance in detail. Single-crystal perovskite was first fabricated as an active material for X-ray detectors, having excellent performance under X-ray illumination due to its superior photoelectric properties of X-ray attenuation with μm thickness. The X-ray detector based on inorganic perovskite shows good environmental stability and high X-ray sensitivity. Owing to anisotropic carrier transport capability, two-dimensional layered perovskites with a preferred orientation parallel to the substrate can effectively suppress the dark current of the device despite poor light response to X-rays, resulting in lower sensitivity for the device. Double perovskite applied for X-ray detectors shows better attenuation of X-rays due to the introduction of high-atomic-numbered elements. Additionally, its stable crystal structure can effectively lower the dark current of X-ray detectors. Environmentally friendly lead-free perovskite exhibits potential application in X-ray detectors by virtue of its high attenuation of X-rays. In the last section, we specifically introduce the up-scaling process technology for fabricating large-area and thick perovskite films for X-ray detectors, which is critical for the commercialization and mass production of perovskite-based X-ray detectors.
Gas hydrates have promising application prospects in the fields of future energy sources, natural gas storage and transportation, CO
capture and sequestration, gas separation, and cold energy. ...However, the application of hydrate technologies is being restricted due to the slow formation rate of gas hydrates. Kinetic promoters have been receiving increased attention, given that they can improve the hydrate formation rate with very small doses and do not affect gas storage capacity. However, most kinetic promoters are non-renewable, petrochemical-derived, non-degradable materials, inevitably leading to resource waste and environmental pollution. Biopromoters, derived from biomass, are renewable, biodegradable, environmentally friendly, non-toxic (or low toxic), and economically feasible. This mini review summarizes the current status of already discovered biopromoters, including lignosulfonate, amino acid, biosurfactant, and biological porous structures, which have the potential to replace petrochemical-derived promoters in hydrate technologies. Finally, future research directions are given for the development of biopromoters.
Mountain uplift and climatic fluctuations are important driving forces that have affected the geographic distribution and population dynamics history of organisms. However, it is unclear how ...geological and climatic events might have affected the phylogeographic history and species divergence in high-alpine herbal plants. In this study, we analyzed the population demographic history and species differentiation of four endangered
herbs on the high-altitude Qinghai-Tibetan Plateau (QTP) and adjacent areas. We combined phylogeographic analysis with species distribution modeling to detect the genetic variations in four
species (
,
,
, and
). In total, 559 individuals from 74 populations of the four species were analyzed based on three maternally inherited chloroplast fragments (
,
, and
S
G) and one nuclear DNA region (internal transcribed spacer, ITS). Fifty-five chloroplast DNA (cpDNA) and 48 ITS haplotypes were identified in the four species. All of the cpDNA and ITS haplotypes were species-specific, except
and
shared one cpDNA haplotype, H32. Phylogenetic analysis suggested that all four species formed a monophyletic clade with high bootstrap support, where
and
were sisters. In addition, each
species generated an individual clade that corresponded to their respective species in the ITS tree. Population dynamics analyses and species distribution modeling showed that the two widely distributed herbs
and
exhibited obvious demographic expansions during the Pleistocene ice ages. Molecular dating suggested that the divergence of the four
species occurred approximately between 3.6 and 1.2 Mya, and it was significantly associated with recent extensive uplifts of the QTP. Our results support the hypothesis that mountain uplift and Quaternary climatic oscillations profoundly shaped the population genetic divergence and demographic dynamics of
species. The findings of this and previous studies provide important insights into the effects of QTP uplifts and climatic changes on phylogeography and species differentiation in high altitude mountainous areas. Our results may also facilitate the conservation of endangered herbaceous medicinal plants in the genus
Macrophages are essential for wound repair after myocardial infarction (MI). CD226, a member of immunoglobulin superfamily, is expressed on inflammatory monocytes, however, the role of CD226 in ...infarct healing and the effect of CD226 on macrophage remain unknown.
Wild type and CD226 knockout (CD226 KO) mice were subjected to permanent coronary ligation. CD226 expression, cardiac function and ventricular remodeling were evaluated. Profile of macrophages, myofibroblasts, angiogenesis and monocytes mobilization were determined.
CD226 expression increased in the infarcted heart, with a peak on day 7 after MI. CD226 KO attenuated infarct expansion and improved infarct healing after MI. CD226 deletion resulted in increased F4/80
CD206
M2 macrophages and diminished Mac-3
iNOS
M1 macrophages accumulation in the infarcted heart, as well as enrichment of α-smooth muscle actin positive myofibroblasts and Ki67
CD31
endothelial cells, leading to increased reparative collagen deposition and angiogenesis. Furthermore, CD226 deletion restrained inflammatory monocytes mobilization, as revealed by enhanced retention of Ly6C
monocytes in the spleen associated with a decrease of Ly6C
monocytes in the peripheral blood, whereas local proliferation of macrophage in the ischemic heart was not affected by CD226 deficiency.
studies using bone marrow-derived macrophages showed that CD226 deletion potentiated M2 polarization and suppressed M1 polarization.
: CD226 expression is dramatically increased in the infarcted heart, and CD226 deletion improves post-infarction healing and cardiac function by favoring macrophage polarization towards reparative phenotype. Thus, inhibition of CD226 may represent a novel therapeutic approach to improve wound healing and cardiac function after MI.
In this study, the authors report a series of conjugated block copolymers, PF‐b‐Piso comprising poly2,7‐(9,9‐dihexylfluorene) (PF), and poly(pendent isoindigo) (Piso) for polymer electret in the ...photonic field‐effect transistor (FET) memory device. The optical properties, surface morphology, and molecular organization of these BCPs are investigated systematically. Accordingly, Piso with absorption in the Ultraviolet C range (UVC, 200–280 nm) possibly rendered the device with a multiband photoresponse, and a good memory performance is achieved by optimizing the polymer composition. Therefore, the memory device comprising PF‐b‐Piso could perform a high current contrast of 106 to 405 nm light and 105 to 254 nm light over 104 s. In addition, a current contrast of 104 and 102 is achieved in response to 650 and 530 nm light, and this phenomenon can be attributed to the charge transfer between channel and memory layers. The experimental results indicate that the block copolymer design not only conduces to forming a self‐assembled microphase separation to stabilize the trapped charge in the polymer electret, but also triggers multiband photoresponding of the photonic FET memory.
A series of poly(fluorene) based conjugated block copolymers with pendent isoindigo coils are applied into multiband photoresponding field‐effect transistor memory. By optimizing the polymer composition, a decent memory discernibility and durability with blue light (405 nm), Ultraviolet A (UVA, 365 nm), and Ultraviolet C (UVC, 254 nm) programming and electrical erasing can be fulfilled.
Traffic-related air pollution has been associated with various health risks for human populations living near roadways. Understanding the relationship between traffic density and dispersion of ...vehicle-released air pollutants is important for assessing human exposure to near-road air pollutants. We performed a literature survey targeting publications containing measurement data of traffic-related air pollutants near roads with distance information on their concentration distribution. Concentration decay rates over down-wind distance away from major roads were calculated for black carbon (BC), carbon monoxide (CO) and nitrogen oxides (NO2 or NOx) and meta-data analysis on these rates was performed. These analyses showed metadata-based exponential decay rates of 0.0026, 0.0019, 0.0004, and 0.0027 m−1 for BC, CO, NO2 and NOx, respectively. Using these measurement data-based decay rates, concentrations for BC, CO, NO2 and NOx over various near-road distances were predicted. These results are useful for enhancing exposure modeling and thus more reliably assessing the health risk of exposure to near road air pollution.
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