RESUMO
Bilayer type CH3NH3PbI3 (MAPbI3) perovskite hybrid solar cells were fabricated via a one-step spin-coating process by using solubility controlled MAPbI3 solutions of MAPbI3-DMSO (dimethyl sulfoxide) and MAPbI3-DMF (N, N-dimethylformamide)-HI. The best DMSO-bilayer device showed 1.07 ± 0.02 V V(oc) (open-circuit voltage), 20.2 ± 0.1 mA cm(-2) J(sc) (short-circuit current density), 68 ± 2% FF (fill factor), and 15.2 ± 0.3% η (overall power conversion efficiency) under the forward scan direction and 1.07 ± 0.02 V V(oc), 20.4 ± 0.1 mA cm(-2) J(sc), 70 ± 3% FF, and 15.9 ± 0.4% η under the reverse scan direction. The best HI-bilayer device had 1.08 ± 0.02 V V(oc), 20.6 ± 0.1 mA cm(-2) J(sc), 75 ± 1% FF, and 17.2 ± 0.2% η under the forward scan direction and 1.08 ± 0.02 V V(oc), 20.6 ± 0.1 mA cm(-2) J(sc), 76 ± 2% FF, and 17.4 ± 0.3% η under the reverse scan direction. The deviation of average device efficiency (η(avg)) of 20 DMSO samples and 20 HI samples was 14.2 ± 0.95% and 16.2 ± 0.85%, respectively. Therefore, the HI-bilayer devices exhibited better device efficiency and smaller J-V (current density-voltage) hysteresis with respect to the scan direction than the DMSO-bilayer devices due to the reduced recombination and traps by the formation of a purer and larger MAPbI3 perovskite crystalline film.
RESUMO
Objective: Acute aortic syndrome (AAS) is a fatal disease with high mortality. There were previous studies using aortic dissection detection risk score (ADD-RS) and D-dimer (DD) to screen AAS. There were screening failures in previous studies, suggesting the need for a more accurate tool. This study investigated the effect of combining ADD-RS and age adjusted D-dimer (DDage-adj) with abnormal findings on chest radiographs on the diagnosis of AAS in patients admitted to emergency department (ED). Methods: This single-center retrospective case-control study included 93 patients with AAS and 465 with chest pain (CP), diagnosis other than AAS. We attempted to compare the initial clinical presentation and laboratory examination findings. Results: Age-adjusted DD (DDage-adj), defined as age x 0.01 mg/L in patients ≥50 years, showed sensitivity of 92.5% and specificity of 76.3% for patients with AAS (p < 0.001). Positive chest radiography findings were significant with AAS group; sensitivity was 89.2% with a specificity of 80.9% (p < 0.001). Multivariate logistic regression analysis was used; widened mediastinum, widening of aortic contour and aortic kinking indicates the probability of AAS in patients with CP (p < 0.05).ADD-RS was used to evaluate the risk of AAS. For low risk group, ADD-RS ≤1, combined use of chest radiography and DDage-adj showed meaningful result. Sensitivity and specificity were 100% and 67.1% with failure rate of 0% (p < 0.001). Multivariate logistic regression analysis were made; widening of the mediastinum (p = 0.035), widening of the aortic contour (p < 0.001) and aortic kinking (p < 0.001) showed significant p-value. Combining DDage-adj and these three chest radiography findings in ADD-RS≤1 patients resulted 0% failure rate with 67.8% specificity (p < 0.001). Conclusions: The combination of ADD-RS, DDage-adj and chest radiography could lower the failure rate of AAS exclusion strategy. This combination strategy satisfies low failure rate (<3%) and yields relatively high specificity of 67.8%.
RESUMO
A power conversion efficiency of 10.4% is demonstrated in planar CH3 NH3 PbBr3 hybrid solar cells without hysteresis of the J-V curve, by way of controlled crystallization in the spin-coating process. The high efficiency is attributed to the formation of a dense CH3 NH3 PbBr3 thin film by the introduction of HBr solution because the HBr increases the solubility of the CH3 NH3 PbBr3 and forms a thinner CH3 NH3 PbBr3 layer with full surface coverage.