Structural templating as a route to improved photovoltaic performance in copper phthalocyanine/fullerene (C60) heterojunctions

We have developed a method to improve the short circuit current density in copper phthalocyanine (CuPc)/fullerene (C60) organic solar cells by ~60% by modifying the CuPc crystal orientation through use of a molecular interlayer to maximize charge transport in the direction between the two electrodes. Powder x-ray diffraction and electronic absorption spectroscopy show that a thin 3,4,9,10-perylenetetracarboxylic dianhydride interlayer before CuPc growth templates the CuPc film structure, forcing the molecules to lie flat with respect to the substrate surface, although the intrastack orientation is unaffected. This modified stacking configuration facilitates charge transport and improves charge collection

No sign of harm : issues for disabled children communicating about abuse

While all children may be the victims of abuse, disabled children are particularly vulnerable. This paper explores the views of professionals working with children using alternative/augmented communication systems on the issues relating to communication about abuse. Interviews were carried out with 20 staff from eight establishments for disabled children across Scotland. It describes the range of alternative/augmented communication systems used and the barriers to communication about abuse. Staff generally accepted the importance of providing the appropriate vocabulary in augmented communication systems, but systems that provide such vocabulary were not widely used. Staff considered that a major difficulty concerned the level of understanding disabled children might have about concepts of abuse. They were unsure how the appropriate vocabulary could be introduced in a natural way and how links could be made between the signs and their meanings. Staff saw themselves as those most able to protect the children, but it was felt that discovery of abuse was more likely to come from them noticing physical signs, behaviour or mood changes than from the child communicating explicitly about abuse. The need for appropriate training and increased coordination between social work, health and education is highlighted

Towards a millivolt optical modulator with nano-slot waveguides

We describe a class of modulator design involving slot waveguides and electro-optic polymer claddings. Such geometries enable massive enhancement of index tuning when compared to more conventional geometries. We present a semi-analytic method of predicting the index tuning achievable for a given geometry and electro-optic material. Based on these studies, as well as previous experimental results, we show designs for slot waveguide modulators that, when realized in a Mach-Zehnder configuration, will allow for modulation voltages that are orders of magnitude lower than the state of the art. We also discuss experimental results for nano-slot waveguides

Small molecule tandem organic photovoltaic cells incorporating an α-NPD optical spacer layer

We report an improvement in power conversion efficiency in a small molecule tandem organic photovoltaic (OPV) device by the optimisation of current balancing of the sub-cells using an optical spacer layer. A co-deposited layer of N,N’-bis(1-naphthyl)-N,N′-diphenyl-1,1’-biphenyl-4,4’-diamine (α-NPD) and molybdenum oxide was used as the optical spacer layer and provided a highly transparent and conductive layer. Optical simulations showed the addition of the optical spacer in a boron subphthalocyanine (SubPc)/C60 based tandem OPV device increased the SubPc absorption in the front sub-cell and resulted in current balancing through the device. Fabricated tandem OPV devices showed similar trends, with the power conversion efficiency increasing from 2.3% to 4.2% with the addition of an optimised optical spacer thickness. External quantum efficiency and total absorption efficiency measurements back up the optical model data which attribute the increased performance to improved SubPc absorption in the front sub-cell, balancing the photocurrents of the two sub-cells

Addressing unwarranted clinical variation in healthcare as a quality improvement process

The reduction of unwarranted clinical variation is a common goal of healthcare systems worldwide. However, the process of developing and implementing variation reducing interventions as a quality improvement process is often overlooked and performed sub-optimally within healthcare organizations. This gap in practice is mirrored by a gap in existing research. The development of a clinical variation specific prescriptive model will assist with the identification, development and application of healthcare specific variation reducing initiatives. Such a model should complement the existing plan, do, study, act quality (PDSA) improvement methodology and respect the learning health systems (LHS) learning cycle. Development through the lens of the quadruple aim of healthcare will ensure that the focus remains true to the core values of clinical organizations. Addressing unwarranted clinical variation is a complex task, however. With organizational support, the utilization of collaborative methodologies and the leveraging of available digital health technologies, healthcare organizations are provided the greatest opportunity for the reduction of unwarranted clinical variation and the optimization of healthcare outcomes

Framing higher education: questions and responses in the British Social Attitudes survey, 1983-2010

This is the final version of the article. Available from Taylor & Francis (Routledge) via the DOI in this record.This article focuses on questions and attitudes towards higher education in the British Social Attitudes (BSA) survey series. First, we analyse the changing BSA questions (1983-2010) in the context of key policy reports. Our results show that changes in the framing of higher education questions correspond with changes in the macro-discourse of higher education policies. Second, we focus on the 2010 BSA survey responses to investigate how attitudes towards higher education are related to respondents' characteristics. Respondents' socio-economic position predicts attitudes towards higher education. Graduates and professionals are most likely to support a reduction in higher education opportunities, but those who have so far benefitted least from higher education are supportive of expansion. One interpretation - with potential implications for social mobility - is that those who have already benefited from higher education are most inclined to pull the ladder up behind them

Comparison of dimethyl sulfoxide treated highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) electrodes for use in indium tin oxide-free organic electronic photovoltaic devices

Indium tin oxide (ITO)-free organic photovoltaic (OPV) devices were fabricated using highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the transparent conductive electrode (TCE). The intrinsic conductivity of the PEDOT:PSS films was improved by two different dimethyl sulfoxide (DMSO) treatments – (i) DMSO was added directly to the PEDOT:PSS solution (PEDOT:PSSADD) and (ii) a pre-formed PEDOT:PSS film was immersed in DMSO (PEDOT:PSSIMM). X-ray photoelectron spectroscopy (XPS) and conductive atomic force microscopy (CAFM) studies showed a large amount of PSS was removed from the PEDOT:PSSIMM electrode surface. OPV devices based on a poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk hetrojunction showed that the PEDOT:PSSIMM electrode out-performed the PEDOT:PSSADD electrode, primarily due to an increase in short circuit current density from 6.62 mA cm−2 to 7.15 mA cm−2. The results highlight the importance of optimising the treatment of PEDOT:PSS electrodes and demonstrate their potential as an alternative TCE for rapid processing and low-cost OPV and other organic electronic devices

Electrochemical behaviour of carbamazepine in acetonitrile and dimethylformamide using glassy carbon electrodes and microelectrodes

The electrochemical reduction of carbamazepine in acetonitrile (ACN) and dimethylformamide (DMF) using a glassy carbon electrode and microelectrodes has been studied. The reduction process is consistent with an Electrochemical-Chemical mechanism (EC) involving a two electron transfer followed by a first order reaction, as shown by the cyclic voltammetry and differential pulse voltammetry. Half-wave potential, number of electron transfer, diffusion coefficient and rate constant of the associated chemical reaction are reported. Detection limits are in DPV: LoD=0.92 and 0.76 μg mL-1 in ACN and DMF, respectively. Precision (%RSD) and recovery (%) values when pharmaceutical compounds (200mg carbamazepine tablets) and spiked plasma samples were tested ranged from 1.09 to 9.04% and % recoveries ranged from 96 to 104.1%