Light-induced photocarrier generation is an essential process in all solar cells, including organic-inorganic hybrid (CH 3 NH 3 PbI 3 ) solar cells, which exhibit a high short-circuit current density (J sc ) of approximately 20 mA/cm 2 . Although the high J sc observed in the hybrid solar cells relies on strong electron-photon interaction, the optical transitions in the perovskite material remain unclear. Here, we report artifact-free CH 3 NH 3 PbI 3 optical constants extracted from ultra-smooth perovskite layers without air exposure and assign all the optical transitions in the visible/ultraviolet region unambiguously based on density functional theory (DFT) analysis that assumes a simple pseudo-cubic crystal structure. From the self-consistent spectroscopic ellipsometry analysis of the ultra-smooth CH 3 NH 3 PbI 3 layers, we find that the absorption coefficients of CH 3 NH 3 PbI 3 (α = 3.8 × 10 4 cm −1 at 2.0 eV) are comparable to those of CuInGaSe 2 and CdTe, and high α values reported in earlier studies are overestimated seriously by extensive surface roughness of CH 3 NH 3 PbI 3 layers. The polarization-dependent DFT calculations show that CH 3 NH 3 + interacts strongly with the
A variety of organic-inorganic hybrid perovskites (APbX 3 ) consisting of mixed center cations [A = CH 3 NH 3 + , HC(NH 2 ) 2 + , Cs + ] with different PbX 3 − cages (X = I, Br, Cl) have been developed to realize high-efficiency solar cells. Nevertheless, clear understanding for the effects of A and X on the optical transition has been lacking. Here, we present MAPbI 3 is replaced with a formamidinium (FA) cation [HC(NH 2 ) 2 + ] having a larger molecular weight. For FAPbI 3 , no major structural change occurs upon thermal treatment up to 150 o C. 46 However, the FAPbI 3 perovskite has limited long-term stability and a cubic FAPbI 3 crystal (α-FAPbI 3 ) shows a gradual phase transformation into a transparent δ-FAPbI 3 phase having a one-dimensional crystal structure. 49,50 Such instability is caused by the larger size of FA + and, quite fortunately, FAPbI 3 -based perovskites can be stabilized by including a small amount of MA + and Cs + having smaller ionic radii. 51-57 The Cs addition to α-FAPbI 3 is also beneficial for suppressing degradation induced by humid air and light illumination. 53 A recent study further demonstrates the improved overall stability of α-FAPbI 3 by the incorporation of Cs and Br atoms. 57 Accordingly, by the optimum combination of different A-site cations and X-site halogen atoms, an ideal hybrid perovskite compound with high stability could be realized. To date, very high conversion efficiencies exceeding 20% have been demonstrated in (FA, MA)Pb(I, Br) 3 and (FA, MA, Cs)Pb(I, Br) 3 solar cells. 52,57-59 Nevertheless, despite the rapid progress for the solar cell fabrication, the optical process in the complex hybrid perovskite remains unclear. For the light absorption in APbX 3 , there is a common belief that the A-site cation plays a minor role in the optical transition 12-19 and only the band gap (E g ) changes slightly according to the size of the A-site cation. 17,20 However, although many studies have been devoted to determine the dielectric functions (ε = ε 1 -iε 2 ) of MAPbI 3 (Refs. 5, 23-27), MAPbBr 3 (Refs. 27, 63) and MAPbCl 3 (Ref. 27), only limited experimental results are available for the quantitative effect of the A-site cation on the light absorption. 53,60,61 So far, the optical properties of FAPbI 3 (Refs. 20, 65) and CsPbI 3 (Refs. 65-67) perovskites have beeninvestigated by applying density functional theory (DFT), but the influences of the A-site cation and X-site halogen atom on the absorption properties remain ambiguous.
In developing photovoltaic devices with high efficiencies, quantitative determination of the carrier loss is crucial. In conventional solar-cell characterization techniques, however, photocurrent reduction originating from parasitic light absorption and carrier recombination within the light absorber cannot be assessed easily. Here, we develop a
These results suggest that, in schizophrenia, regional thalamocortical white matter pathology is specifically associated with cortical pathology in regions where fibers connect.
S evere fever with thrombocytopenia syndrome (SFTS) is caused by the species Dabie bandavirus (family Phenuiviridae, genus Bandavirus), generally called severe fever with thrombocytopenia syndrome virus (SFTSV) (1,2). Cases of SFTS were identified in patients in China during 2009 (3) and subsequently in Japan and South Korea (2,4). Clinical signs include high fever, fatigue, gastrointestinal symptoms, neurologic symptoms, thrombocytopenia, leukocytopenia, and multiorgan failure (5). SFTS is potentially fatal, and mortality rates have reached 27% in Japan (6). Although the clinical information regarding SFTS in most animals is unclear, cats show fatal symptoms similar to those in humans (7). Enzootic SFTSV transmission is primarily tickborne; tick bites can also spread the virus to humans (8) and animals (9). Human-to-human transmission occurs rarely through contact with infected blood, body fluids, or mucus (10) and possibly by aerosols (11). In this study, we provide evidence for the direct cat-to-human transmission of the virus, leading to a nosocomial outbreak of SFTSV infection. The Study Confirmatory testing of veterinary personnel samples was performed at the Laboratory of Microbiology, Miyazaki Prefecture Institute for the Public Health and Environment, Miyazaki, Japan. Cat sample analysis was performed at the Center for Animal Disease Control, University of Miyazaki. A 1-year-old male domestic cat was hospitalized on August 15, 2018, with jaundice, poor appetite, vomiting, and a rectal temperature of 40.4°C. Hematologic examination showed leukocytopenia (1,080 cells/µL, reference range 4-30 × 10 3 cells/µL), thrombocytopenia (19,000 cells/µL, reference range 9-90 × 10 4 cells/µL), and an increased level of total bilirubin (3.1 mg/dL, reference range 0-0.5 mg/dL) (12) (Table). The cat died 3 days after hospitalization. Serum samples, saliva samples, and anal swab specimens (sampled on the first day of hospitalization) were sent to the Center for Animal Disease Control, University of Miyazaki, for molecular test targeting the small segment RNA of SFTSV by reverse transcription PCR (RT-PCR) and real-time RT-PCR (3). The amounts of SFTSV RNA were quantified as RNA copies per milliliter of serum. We detected a viral load of 1.5 × 10 11 copies/mL (Table). During hospitalization, the cat came into contact with a veterinarian (44-year-old woman) and a veterinary technician (20-year-old woman). During contact, both veterinary personnel wore protective clothing (gloves and surgical masks), but their eyes remained unprotected; they were not bitten or scratched by the cat. In addition, neither was bitten by ticks. After the death of the cat, symptoms consistent with SFTS developed in both veterinary personnel (Figure 1). Ten days after the death of the cat, on August 27, the veterinarian (patient 1) was hospitalized with a high fever (body temperature 39.2°C),
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