Exploring the Infiltration Features of Perovskite within Mesoporous Carbon Stack Solar Cells Using Broad Beam Ion Milling.

Carbon perovskite solar cells (C-PSCs) are a popular photovoltaic technology currently undergoing extensive development on the global research scene. Whilst their record efficiency now rivals that of silicon PV in small-scale devices, C-PSCs still require considerable development to progress to a commercial-scale product. This study is the first of its kind to use broad beam ion milling for C-PSCs. It investigates how the carbon ink, usually optimised for maximum sheet conductivity, impacts the infiltration of the perovskite into the active layers, which in turn impacts the performance of the cells. Through the use of secondary electron microscopy with energy-dispersive X-ray spectroscopy, infiltration defects were revealed relating to carbon flake orientation. The cross sections imaged showed between a 2% and 100% inactive area within the C-PSCs due to this carbon blocking effect. The impact of these defects on the performance of solar cells is considerable, and by better understanding these defects devices can be improved for mass manufacture.

Characterization of pulp derived nanocellulose hydrogels using AVAP® technology.

Bioinspiration from hierarchical structures found in natural environments has heralded a new age of advanced functional materials. Nanocellulose has received significant attention due to the demand for high-performance materials with tailored mechanical, physical and biological properties. In this study, nanocellulose fibrils, nanocrystals and a novel mixture of fibrils and nanocrystals (blend) were prepared from softwood biomass using the AVAP® biorefinery technology. These materials were characterized using transmission and scanning electron microscopy, and atomic force microscopy. This analysis revealed a nano- and microarchitecture with extensive porosity. Notable differences included the nanocrystals exhibiting a compact packing of nanorods with reduced porosity. The NC blend exhibited porous fibrillar networks with interconnecting compact nanorods. Fourier transform infrared spectroscopy and X-ray diffraction confirmed a pure cellulose I structure. Thermal studies highlighted the excellent stability of all three NC materials with the nanocrystals having the highest decomposition temperature. Surface charge analysis revealed stable colloid suspensions. Rheological studies highlighted a dominance of elasticity in all variants, with the NC blend being more rigid than the NC fibrils and nanocrystals, indicating a double network hydrogel structure. Given these properties, it is thought that these materials show great potential in (bio)nanomaterial applications where careful control of microarchitecture, surface topography and porosity are required.

One-step growth of thin film SnS with large grains using MOCVD.

Thin film tin sulphide (SnS) films were produced with grain sizes greater than 1 µm using a one-step metal organic chemical vapour deposition process. Tin-doped indium oxide (ITO) was used as the substrate, having a similar work function to molybdenum typically used as the back contact, but with potential use of its transparency for bifacial illumination. Tetraethyltin and ditertiarybutylsulphide were used as precursors with process temperatures 430-470 °C to promote film growth with large grains. The film stoichiometry was controlled by varying the precursor partial pressure ratios and characterised with energy dispersive X-ray spectroscopy to optimise the SnS composition. X-ray diffraction and Raman spectroscopy were used to determine the phases that were present in the film and revealed that small amounts of ottemannite Sn2S3 was present when SnS was deposited on to the ITO using optimised growth parameters. Interaction at the SnS/ITO interface to form Sn2S3 was deduced to have resulted for all growth conditions.

Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis.

Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with "Janus-like" characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.

Facile self-assembly and stabilization of metal oxide nanoparticles.

This paper describes a facile method of self-assembling different metal oxide nanoparticles into nanostructured materials via di-carboxylate linkers (oxalic acid) using TiO2 as an example. In this method, the di-carboxylate linkers react with surface hydroxyls on metal oxide nanoparticles forming covalent, ester-like bonds, which enable the binding of two metal oxide particles, one at either end of the linker and facilitates efficient self-assembly of one group of metal oxide nanoparticles homogeneously distributed onto the surface of another group. The oxalate linkers can then be removed by thermal decomposition. This approach is shown to be effective using differently-sized TiO2 nanoparticles, namely in-house synthesized 3-5nm anatase nanocrystals and Degussa P25 titania particles (mean 21nm particle size). Our data show that the application of a high temperature heat treatment (450°C for 30min), conventionally applied to achieve a stable porous structure by thermal decomposition of the linker molecules and by inducing inter-particle necking, damages the surface area of the nanostructured material. However, here we show that sintering at 300°C for 30min or by flash near infrared radiation sintering for 12s efficiently decomposes the oxalate linkers and stabilizes the nanostructure of the material whilst maintaining its high surface area.

A one-step low temperature processing route for organolead halide perovskite solar cells.

Organolead trihalide perovskite solar cells based upon the co-deposition of a combined Al2O3-perovskite layer at T < 110 °C are presented. We report an average PCE = 7.2% on a non-sintered Al2O3 scaffold in devices that have been manufactured from a perovskite precursor containing 5 wt% Al2O3 nanoparticles.

QOLLTI-F: measuring family carer quality of life.

BACKGROUND: The primary goal of palliative care is to optimize the quality of life (QOL) of people living with a life-threatening illness and that of their families. While there have been important advances in measurement of the QOL of palliative care patients, little attention has been paid to the QOL of their carers (family caregivers). To develop and deliver the most effective services to these carers, their QOL needs to be measured with acceptable and psychometrically sound instruments that have content validity. METHODS: This study reports three phases of the development and testing of such a measure: QOLLTI-F, Quality of Life in Life Threatening Illness--Family Carer Version, simultaneously in English and French. Participants were carers from 12 Canadian palliative care services who were asked to complete QOLLTI-F on three occasions. RESULTS: The final version of QOLLTI-F consists of 16 items. It was deemed acceptable by the vast majority of carers and a longer, 24-item version was completed in a median of 12 min. Content validity was assured by inclusion of all domains reported by carers to be important to their QOL: state of carer, patient wellbeing, quality of care, outlook, environment, finances and relationships. Construct validity was demonstrated, as principal components analysis indicated that the 16 items did indeed reflect these seven domains. Furthermore, the seven domain scores predicted 53% of the variance in global QOL, although the QOLLTI-F Total score predicted less well (43%). The test-retest reliability for the QOLLTI-F Total score was 0.77-0.80 and ranged from 0.50 to 0.79 for the seven domain scores. All QOLLTI-F scores were shown to be significantly different between days the carers considered bad, average and good, demonstrating responsiveness to change, with the exception of the Financial Concerns submeasure, which did not distinguish between average and good days. CONCLUSIONS: QOLLTI-F is unique in that in measuring one person's QOL (the carer's) it includes their perception of the condition of another (the patient). This attests to the close relationship between the two. It is also unique in that its content is derived from a qualitative study asking carers what is important to their own QOL, rather than focusing on the changes or burdens related to caregiving. QOLLTI-F also has the advantage of being briefer than other carer QOL measures. It contains measures of seven different domains that are determinants of carer QOL, in addition to a summary score. All these measures are valid, reliable and responsive to change in QOL.

Caring for a loved one with advanced cancer: determinants of psychological distress in family caregivers.

BACKGROUND: Family caregivers caring for a patient with terminal cancer may experience significant psychological distress. OBJECTIVE: The purpose of this study was to determine the extent to which the family caregivers' psychological distress is influenced by the patients' performance status while taking into account individual characteristics of caregivers and their unmet needs. METHODS: Two hundred twelve family caregivers were assigned to three cohorts according to the patient's performance status, as measured by the Eastern Collaborative Oncology Group Functional Scale (ECOGS). Interview information was collected on the services and care provided, as well as on the caregivers' characteristics and level of psychological distress. RESULTS: Family caregivers' psychosocial distress is strongly associated with the patients' terminal disease progress and declined functioning. The level of psychological distress varies from 25.2 to 33.5 (p = 0.0008) between the groups. Moreover, the percentage of caregivers with a high level of psychological distress varies from 41% to 62%, while this percentage is estimated at 19.2% in general population. A high distress index was significantly associated with the caregiver's burden, the patient's young age, the patient's symptoms, the caregiver's young age and gender, a poor perception of his/her health and dissatisfaction with emotional and tangible support. CONCLUSIONS: Family caregivers of patients in the advanced stages of cancer experience a high level of psychological distress, which increases significantly as the patient loses autonomy. Health care policies and programs need to be revisited in order to take the reality of these patients and their families into account.

Delirium in advanced cancer: a psychoeducational intervention for family caregivers.

Delirium, a global brain dysfunction, develops frequently in advanced cancer. It is a leading source of distress for family caregivers. Following recommendations from palliative care professionals and caregivers for terminally ill cancer patients, a psychoeducational intervention was implemented in a palliative care hospice to help family caregivers cope with delirium and, eventually, to contribute to early detection. Prior to receiving information on delirium, the majority of the family caregivers did not know what it was or that it could be treated. Few knew that patients in terminal care could become delirious. For caregivers, receiving the intervention increased their confidence they were making good decisions, and the majority felt that all family caregivers should be informed on the risk of delirium (p < 0.009). A specific intervention on delirium, tailored to the needs of the family caregivers, seems beneficial for caregivers and for patients.

[The quality of sibling relation who have experienced family transitions and those who have not]. / La qualité des relations fraternelles chez des jeunes ayant connu ou non une transition familiale.

In this study, similarities and differences in sibling relationships between children who have experienced family transitions and those who have not are examined. Comparisons are made between children who live in intact families, those whose parents have separated, and those who live in substitute care regarding the quality of their relationships with one of their siblings. More specifically, 4 dimensions describing the quality of sibling relationships are compared: Warmth/Closeness, Conflict, Relative Status/Power, and Rivalry (Furman & Buhrmester, 1985). The sample is made up of 3 groups of children (N = 158) aged between 8 and 12 years old: children living in intact families (n = 101), children who have experienced parental separation (n = 35), and children living in substitute care (n = 22). Results indicate differences on dimensions of Warmth/Closeness, Conflict, and Relative Status/Power. Different patterns of responses between the children who have experienced family transitions and those who have not are observed for the dimensions of Conflict and Power. The significant difference observed between the groups for the dimension of Warmth appears difficult to explain. Discussion of these results emphasizes the importance of the relationship between brothers and sisters experiencing family transition.