We report a retrospectively identified fatal case of severe fever with thrombocytopenia syndrome (SFTS) in South Korea from 2012. SFTS virus was isolated from the stored blood of the patient. ...Phylogenetic analysis revealed this isolate was closely related to SFTS virus strains from China and Japan.
Highly efficient p-i-n perovskite solar cells employing a flat and thick CH sub(3)NH sub(3)PbI sub(3 ) film and a thin PCBM film are fabricated by the solution-process at low temperature. Through ...attainment of optimized PCBM thickness and insertion of the LiF interlayer, the unit cell shows 14.1% of overall power conversion efficiency (PCE) with a J sub(sc) of 20.7 mA cm super(-2), a V sub(oc) of 0.866 V, and a FF of 78.3% under AM 1.5G 100 mW cm super(-2) conditions, while a larger area 10 cell serially connected module (10 10 cm super(2)) shows an 8.7% PCE. These PCE values are the highest reported to date for the planar perovskite-PCBM solar cells.
The formation of a dense and uniform thin layer on the substrates is crucial for the fabrication of high-performance perovskite solar cells (PSCs) containing formamidinium with multiple cations and ...mixed halide anions. The concentration of defect states, which reduce a cell’s performance by decreasing the open-circuit voltage and short-circuit current density, needs to be as low as possible. We show that the introduction of additional iodide ions into the organic cation solution, which are used to form the perovskite layers through an intramolecular exchanging process, decreases the concentration of deep-level defects. The defect-engineered thin perovskite layers enable the fabrication of PSCs with a certified power conversion efficiency of 22.1% in small cells and 19.7% in 1-square-centimeter cells.
Metal halide perovskite solar cells (PSCs) are an emerging photovoltaic technology with the potential to disrupt the mature silicon solar cell market. Great improvements in device performance over ...the past few years, thanks to the development of fabrication protocols
, chemical compositions
and phase stabilization methods
, have made PSCs one of the most efficient and low-cost solution-processable photovoltaic technologies. However, the light-harvesting performance of these devices is still limited by excessive charge carrier recombination. Despite much effort, the performance of the best-performing PSCs is capped by relatively low fill factors and high open-circuit voltage deficits (the radiative open-circuit voltage limit minus the high open-circuit voltage)
. Improvements in charge carrier management, which is closely tied to the fill factor and the open-circuit voltage, thus provide a path towards increasing the device performance of PSCs, and reaching their theoretical efficiency limit
. Here we report a holistic approach to improving the performance of PSCs through enhanced charge carrier management. First, we develop an electron transport layer with an ideal film coverage, thickness and composition by tuning the chemical bath deposition of tin dioxide (SnO
). Second, we decouple the passivation strategy between the bulk and the interface, leading to improved properties, while minimizing the bandgap penalty. In forward bias, our devices exhibit an electroluminescence external quantum efficiency of up to 17.2 per cent and an electroluminescence energy conversion efficiency of up to 21.6 per cent. As solar cells, they achieve a certified power conversion efficiency of 25.2 per cent, corresponding to 80.5 per cent of the thermodynamic limit of its bandgap.
Abstract
Driven by recent improvements in efficiency and stability of perovskite solar cells (PSCs), upscaling of PSCs has come to be regarded as the next step. Specifically, a high-throughput, ...low-cost roll-to-roll (R2R) processes would be a breakthrough to realize the commercialization of PSCs, with uniform formation of precursor wet film and complete conversion to perovskite phase via R2R-compatible processes necessary to accomplish this goal. Herein, we demonstrate the pilot-scale, fully R2R manufacturing of all the layers except for electrodes in PSCs. Tert-butyl alcohol (tBuOH) is introduced as an eco-friendly antisolvent with a wide processing window. Highly crystalline, uniform formamidinium (FA)-based perovskite formation via tBuOH:EA bathing was confirmed by achieving high power conversion efficiencies (PCEs) of 23.5% for glass-based spin-coated PSCs, and 19.1% for gravure-printed flexible PSCs. As an extended work, R2R gravure-printing and tBuOH:EA bathing resulted in the highest PCE reported for R2R-processed PSCs, 16.7% for PSCs with R2R-processed SnO
2
/FA-perovskite, and 13.8% for fully R2R-produced PSCs.
Of the many materials and methodologies aimed at producing low-cost, efficient photovoltaic cells, inorganic-organic lead halide perovskite materials appear particularly promising for next-generation ...solar devices owing to their high power conversion efficiency. The highest efficiencies reported for perovskite solar cells so far have been obtained mainly with methylammonium lead halide materials. Here we combine the promising-owing to its comparatively narrow bandgap-but relatively unstable formamidinium lead iodide (FAPbI3) with methylammonium lead bromide (MAPbBr3) as the light-harvesting unit in a bilayer solar-cell architecture. We investigated phase stability, morphology of the perovskite layer, hysteresis in current-voltage characteristics, and overall performance as a function of chemical composition. Our results show that incorporation of MAPbBr3 into FAPbI3 stabilizes the perovskite phase of FAPbI3 and improves the power conversion efficiency of the solar cell to more than 18 per cent under a standard illumination of 100 milliwatts per square centimetre. These findings further emphasize the versatility and performance potential of inorganic-organic lead halide perovskite materials for photovoltaic applications.
Three spiro-OMeTAD derivatives have been synthesized and characterized by 1H/13C NMR spectroscopy and mass spectrometry. The optical and electronic properties of the derivatives were modified by ...changing the positions of the two methoxy substituents in each of the quadrants, as monitored by UV–vis spectroscopy and cyclic voltammetry measurements. The derivatives were employed as hole-transporting materials (HTMs), and their performances were compared for the fabrication of mesoporous TiO2/CH3NH3PbI3/HTM/Au solar cells. Surprisingly, the cell performance was dependent on the positions of the OMe substituents. The derivative with o-OMe substituents showed highly improved performance by exhibiting a short-circuit current density of 21.2 mA/cm2, an open-circuit voltage of 1.02 V, and a fill factor of 77.6% under 1 sun illumination (100 mW/cm2), which resulted in an overall power conversion efficiency (PCE) of 16.7%, compared to ∼15% for conventional p-OMe substituents. The PCE of 16.7% is the highest value reported to date for perovskite-based solar cells with spiro-OMeTAD.
The band gap of formamidinium lead iodide (FAPbl3) perovskites allows broader absorption of the solar spectrum relative to conventional methylammonium lead iodide (MAPbl3). Because the optoelectronic ...properties of perovskite films are closely related to film quality, deposition of dense and uniform films is crucial for fabricating high-performance perovskite solar cells (PSCs). We report an approach for depositing high-quality FAPbl3 films, involving FAPbl3 crystallization by the direct intramolecular exchange of dimethylsulfoxide (DMSO) molecules intercalated in Pbl2 with formamidinium iodide. This process produces FAPbl3 films with (111)-preferred crystallographic orientation, large-grained dense microstructures, and flat surfaces without residual Pbl2. Using films prepared by this technique, we fabricated FAPbl3-based PSCs with maximum power conversion efficiency greater than 20%.
We investigated the kinetics of the Middle East respiratory syndrome coronavirus (MERS-CoV) neutralizing and spike protein antibody titers over the course of 1 year in 11 patients who were confirmed ...by reverse transcription PCR to have been infected during the outbreak in South Korea in 2015. Robust antibody responses were detected in all survivors who had severe disease; responses remained detectable, albeit with some waning, for <1 year. The duration of viral RNA detection (but not viral load) in sputum significantly correlated with the antibody response magnitude. The MERS S1 ELISA antibody titers correlated well with the neutralizing antibody response. Antibody titers in 4 of 6 patients who had mild illness were undetectable even though most had evidence of pneumonia. This finding implies that MERS-CoV seroepidemiologic studies markedly underestimate the extent of mild and asymptomatic infection. Obtaining convalescent-phase plasma with high antibody titers to treat MERS will be challenging.
Besides the generated photocurrent as a key factor that impacts the efficiency of solar cells, the produced photovoltage and fill factor are also of critical importance. Therefore, understanding and ...optimization of the open-circuit voltage (V sub(oc)) of perovskite solar cells, especially with an architecture consisting of mesoporous (mp)-TiO sub(2)/perovskite/hole transporting materials (HTMs), are required to further improve the conversion efficiency. In this work, we study the effects of the energy level between CH sub(3)NH sub(3)(= MA)PbI sub(3) and MAPbBr sub(3) and a series of triarylamine polymer derivatives containing fluorene and indenofluorene, which have different highest occupied molecular orbital (HOMO) levels, in terms of the photovoltaic behaviour. The voltage output of the device is found to be dependent on the higher energy level of perovskite solar absorbers as well as the HOMO level of the HTMs. The combination of MAPbBr sub(3) and a deep-HOMO HTM leads to a high photovoltage of 1.40 V, with a fill factor of 79% and an energy conversion efficiency of up to 6.7%, which is the highest value reported to date for MAPbBr sub(3) perovskite solar cells.
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