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Solution-manufacturing of organic solar cells with best-in-class power conversion efficiency (PCE) will require all layers to be solution-coated without compromising solar cell performance. To date, the hole transporting layer (HTL) deposited on top of the organic bulk heterojunction layer in the inverted architecture is most commonly an ultrathin (<10 nm) metal oxide layer prepared by vacuum-deposition. Here, we show that an alcohol-based nanocrystalline MoO x suspension with carefully controlled nanocrystal (NC) size can yield state of the art reflective and semitransparent solar cells. Using NCs smaller than the target HTL thickness (∼10 nm) can yield compact, pinhole-free films which result in highly efficient polymer:fullerene bulk heterojunction (BHJ) solar cells with PCE=9.5%. The solution processed HTL is shown to achieve performance parity with vacuum-evaporated HTLs for several polymer:fullerene combinations and is even shown to work as hole injection layer in polymer light emitting diodes (PLED). We also demonstrate that larger MoO x NCs (30–50 nm) successfully composite MoO x with Ag nanowires (NW) to form a highly conducting, transparent top anode with exceptional contact properties. This yields state-of-the-art semitransparent polymer: fullerene solar cells with PCE of 6.5% and overall transmission >30%. The remarkable performance of reflective and semitransparent OPVs is due to the uncommonly high fill factors achieved using a carefully designed strategy for implementation of MoO x nanocrystals as HTL materials. [ABSTRACT FROM AUTHOR]

Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole-transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, is also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films. [ABSTRACT FROM AUTHOR]

Human chorionic gonadotropin (hCG) is a key diagnostic marker of pregnancy. A sensor device for detection of hCG has been fabricated using a CNT (carbon nanotube) screen printed electrode (SPE). The CNT working electrode was first electrochemically oxidised to yield a hydroxyl terminated surface, which was subsequently silanized to produce an amine terminated CNT. The aminated surface allowed oriented binding of an antibody (Ab) bioreceptor, targeted against hCG (anti-hCG), to the CNT-SPE. This was achieved by activating the -COOH group at the Fc terminal of the antibody and incubating the SPE-CNT-NH2 electrode in the activated Ab solution.Electrochemical Impedance Spectroscopy (EIS) and Raman Spectrometry with Confocal Microscopy studies were performed at each stage of the chemical modification process in order to confirm the resulting surface changes associated with each functionalization process.The SPE-CNT-NH2-Ab devices displayed linear responses to hCG in EIS assays in the concentration range from 0.01×10−9gcm−3 to 100×10−9gcm−3. High specificity was observed with respect to hCG detected in solutions containing urine components-these components producing a negligible change in the sensor readout relative to changes induced by hCG. Successful hCG detection was also achieved using real urine samples from pregnant woman.Overall, the immunosensor developed is a promising tool for detecting hCG in a point-of-care diagnostic (POC), due to the excellent detection capability, simplicity of fabrication, low cost, high sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

Heat stress causes morbidity and mortality and is increasing with climate change. Heat stress can pose particular challenges in northern regions not well adapted to heat. To assist decision makers, we identified the relative vulnerability of census tracts within Michigan to factors that increase exposure to heat stress or reflect susceptibilities in the population based on a California heat vulnerability index. In the MI-Environment assessment, we used a Geographic Information System (GIS) to combine future ensemble climate model projections to create a total of 9 geospatial and demographic variables. As part of a broader planned cumulative environmental exposure assessment, the statewide heat vulnerability index (HVI) maps display the location and relative magnitude of exposure on three metrics: built environment (Place), future expected long-term temperature averages (Temperature), and population susceptibility (People). We observed varied and distinct patterns for each of the three component indices. We assessed how equitably those exposures are distributed by racial and socioeconomic factors. This analysis showed that each of the component indices and the aggregate HVI are disproportionately distributed along racial and socioeconomic lines in Michigan. Census tracts with higher percentages of people of color had larger exposure to HVI factors with a deviation from equity of -0.115 [95% CI -0.108, -0.122]. Similarly, for census tracts with higher percentage of people experiencing poverty, the deviation from equity was -0.101 [95% CI -0.094, -0.107]. The MI-Environment visualization tool can help communities prepare for climate change and resolve inequities by identifying census tracts with the most vulnerable residents and highest potential exposures. [ABSTRACT FROM AUTHOR]