Solution-Processed Phototransistors Combining Organic Absorber and Charge Transporting Oxide for Visible to Infrared Light Detection.

This report demonstrates high-performance infrared phototransistors that use a broad-band absorbing organic bulk heterojunction (BHJ) layer responsive from the visible to the shortwave infrared, from 500 to 1400 nm. The device structure is based on a bilayer transistor channel that decouples charge photogeneration and transport, enabling independent optimization of each process. The organic BHJ layer is improved by incorporating camphor, a highly polarizable additive that increases carrier lifetime. An indium zinc oxide transport layer with high electron mobility is employed for rapid charge transport. As a result, the phototransistors achieve a dynamic range of 127 dB and reach a specific detectivity of 5 × 1012 Jones under a low power illumination of 20 nW/cm2, outperforming commercial germanium photodiodes in the spectral range below 1300 nm. The photodetector metrics are measured with respect to the applied voltage, incident light power, and temporal bandwidth, demonstrating operation at a video-frame rate of 50 Hz. In particular, the frequency and light dependence of the phototransistor characteristics are analyzed to understand the change in photoconductive gain under different working conditions

Synthesis and Characterization of [Fe(Htrz)\u3csub\u3e2\u3c/sub\u3e(trz)](BF\u3csub\u3e4\u3c/sub\u3e)] Nanocubes

Compounds that exhibit spin-crossover (SCO) type behavior have been extensively investigated due to their ability to act as molecular switches. Depending on the coordinating ligand, in this case 1H-1,2,4-triazole, and the crystallite size of the SCO compound produced, the energy requirement for the spin state transition can vary. Here, SCO [Fe(Htrz)2(trz)](BF4)] nanoparticles were synthesized using modified reverse micelle methods. Reaction conditions and reagent ratios are strictly controlled to produce nanocubes of 40–50 nm in size. Decreases in energy requirements are seen in both thermal and magnetic transitions for the smaller sized crystallites, where, compared to bulk materials, a decrease of as much as 20 °C can be seen in low to high spin state transitions

Broadband Infrared Photodetection Using a Narrow Bandgap Conjugated Polymer

Photodetection spanning the short-, mid-, and long-wave infrared (SWIR-LWIR) underpins modern science and technology. Devices using state-of-the-art narrow bandgap semiconductors require complex manufacturing, high costs, and cooling requirements that remain prohibitive for many applications. We report high-performance infrared photodetection from a donor-acceptor conjugated polymer with broadband SWIR-LWIR operation. Electronic correlations within the π-conjugated backbone promote a high-spin ground state, narrow bandgap, long-wavelength absorption, and intrinsic electrical conductivity. These previously unobserved attributes enabled the fabrication of a thin-film photoconductive detector from solution, which demonstrates specific detectivities greater than 2.10 × 109 Jones. These room temperature detectivities closely approach those of cooled epitaxial devices. This work provides a fundamentally new platform for broadly applicable, low-cost, ambient temperature infrared optoelectronics

A fractionally cointegrated VAR analysis of economic voting and political support

We use a fractionally cointegrated vector autoregressive model to examine the relationship between Canadian political support and macroeconomic conditions. This model is well suited for the analysis because it allows multiple fractional time series and admits simple asymptotic inference for the model parameters and tests of the hypotheses of interest. In the long-run equilibrium, we find that support for the Progressive Conservative Party was higher during good economic times, i.e. periods of high interest rates and low unemployment, while support for the Liberal Party was higher during bad economic times, i.e. periods of low interest rates and high unemployment. We also test and reject the notion that party support is driven only by relative (to the United States) economic performance. Indeed, our findings suggest that US macroeconomic variables do not enter the long-run equilibrium of Canadian economic voting (political opinion poll support) at all

Organic Bulk Heterojunction Infrared Photodiodes for Imaging Out to 1300 nm

This work studies organic bulk heterojunction photodiodes with a wide spectral range capable of imaging out to 1.3 μm in the shortwave infrared. Adjustment of the donor-to-acceptor (polymer:fullerene) ratio shows how blend composition affects the density of states (DOS) which connects materials composition and optoelectronic properties and provides insight into features relevant to understanding dispersive transport and recombination in the narrow bandgap devices. Capacitance spectroscopy and transient photocurrent measurements indicate the main recombination mechanisms arise from deep traps and poor extraction from accumulated space charges. The amount of space charge is reduced with a decreasing acceptor concentration; however, this reduction is offset by an increasing trap DOS. A device with 1:3 donor-to-acceptor ratio shows the lowest density of deep traps and the highest external quantum efficiency among the different blend compositions. The organic photodiodes are used to demonstrate a single-pixel imaging system that leverages compressive sensing algorithms to enable image reconstruction

Hepatic resection for hepatocellular carcinoma in patients with Child–Pugh's A cirrhosis: is clinical evidence of portal hypertension a contraindication?

AbstractBackgroundAccording to international guidelines [European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD)], portal hypertension (PHTN) is considered a contraindication for liver resection for hepatocellular carcinoma (HCC), and patients should be referred for other treatments. However, this statement remains controversial. The aim of this study was to elucidate surgical outcomes of minor hepatectomies in patients with PHTN (defined by the presence of esophageal varices or a platelet count of <100 000 in association with splenomegaly) and well‐compensated liver disease.MethodsBetween 1997 and 2012, a total of 223 cirrhotic patients [stage A according to the Barcelona Clinic Liver Cancer (BCLC) classification] were eligible for this analysis and were divided into two groups according to the presence (n = 63) or absence (n = 160) of PHTN. The demographic data were comparable in the two patient groups.ResultsOperative mortality was not different (only one patient died in the PHTN group). However, patients with PHTN had higher liver‐related morbidity (29% versus 14%; P = 0.009), without differences in hospital stay (8.8 versus 9.8 days, respectively). The PHTN group showed a worse survival rate only if biochemical signs of liver decompensation existed. Multivariate analysis identified albumin levels as an independent predictive factor for survival.ConclusionsPHTN should not be considered an absolute contraindication to a hepatectomy in cirrhotic patients. Patients with PHTN have short‐ and long‐term results similar to patients with normal portal pressure. A limited hepatic resection for early‐stage tumours is an option for Child–Pugh class A5 patients with PHTN