Assessing the suitability of copper thiocyanate as a hole-transport layer in inverted CsSnI3 perovskite photovoltaics

We report the fndings of a study into the suitability of copper (I) thiocyanate (CuSCN) as a hole-transport layer in inverted photovoltaic (PV) devices based on the black gamma phase (B-γ) of CsSnl3 perovskite. Remarkably, when B-γ-CsSnI3 perovskite is deposited from a dimethylformamide solution onto a 180–190nm thick CuSCN flm supported on an indium-tin oxide (ITO) electrode, the CuSCN layer is completely displaced leaving a perovskite layer with high uniformity and coverage of the underlying ITO electrode. This fnding is confrmed by detailed analysis of the thickness and composition of the film that remains after perovskite deposition, together with photovoltaic device studies. The results of this study show that, whilst CuSCN has proved to be an excellent hole-extraction layer for high performance lead-perovskite and organic photovoltaics, it is unsuitable as a hole-transport layer in inverted B-γCsSnI3 perovskite photovoltaics processed from solution

Metal halide perovskites for energy applications

Exploring prospective materials for energy production and storage is one of the biggest challenges of this century. Solar energy is one of the most important renewable energy resources, due to its wide availability and low environmental impact. Metal halide perovskites have emerged as a class of semiconductor materials with unique properties, including tunable bandgap, high absorption coefficient, broad absorption spectrum, high charge carrier mobility and long charge diffusion lengths, which enable a broad range of photovoltaic and optoelectronic applications. Since the first embodiment of perovskite solar cells showing a power conversion efficiency of 3.8%, the device performance has been boosted up to a certified 22.1% within a few years. In this Perspective, we discuss differing forms of perovskite materials produced via various deposition procedures. We focus on their energy-related applications and discuss current challenges and possible solutions, with the aim of stimulating potential new applications

Green fabrication of stable lead-free bismuth based perovskite solar cells using a non-toxic solvent

The very fast evolution in certified efficiency of lead-halide organic-inorganic perovskite solar cells to 24.2%, on par and even surpassing the record for polycrystalline silicon solar cells (22.3%), bears the promise of a new era in photovoltaics and revitalisation of thin film solar cell technologies. However, the presence of toxic lead and particularly toxic solvents during the fabrication process makes large-scale manufacturing of perovskite solar cells challenging due to legislation and environment issues. For lead-free alternatives, non-toxic tin, antimony and bismuth based solar cells still rely on up-scalable fabrication processes that employ toxic solvents. Here we employ non-toxic methyl-acetate solution processed (CH3NH3)3Bi2I9 films to fabricate lead-free, bismuth based (CH3NH3)3Bi2I9 perovskites on mesoporous TiO2 architecture using a sustainable route. Optoelectronic characterization, X-ray diffraction and electron microscopy show that the route can provide homogeneous and good quality (CH3NH3)3Bi2I9 films. Fine-tuning the perovskite/hole transport layer interface by the use of conventional 2,2′,7,7′-tetrakis (N,N′-di-p-methoxyphenylamino)−9,9′-spirbiuorene, known as Spiro-OMeTAD, and poly(3-hexylthiophene-2,5-diyl - P3HT as hole transporting materials, yields power conversion efficiencies of 1.12% and 1.62% under 1 sun illumination. Devices prepared using poly(3-hexylthiophene-2,5-diyl hole transport layer shown 300 h of stability under continuous 1 sun illumination, without the use of an ultra violet-filter

Progress on lead-free metal halide perovskites for photovoltaic applications: a review

ABSTRACT: Metal halide perovskites have revolutionized the field of solution-processable photovoltaics. Within just a few years, the power conversion efficiencies of perovskite-based solar cells have been improved significantly to over 20%, which makes them now already comparably efficient to silicon-based photovoltaics. This breakthrough in solution-based photovoltaics, however, has the drawback that these high efficiencies can only be obtained with lead-based perovskites and this will arguably be a substantial hurdle for various applications of perovskite-based photovoltaics and their acceptance in society, even though the amounts of lead in the solar cells are low. This fact opened up a new research field on lead-free metal halide perovskites, which is currently remarkably vivid. We took this as incentive to review this emerging research field and discuss possible alternative elements to replace lead in metal halide perovskites and the properties of the corresponding perovskite materials based on recent theoretical and experimental studies. Up to now, tin-based perovskites turned out to be most promising in terms of power conversion efficiency; however, also the toxicity of these tin-based perovskites is argued. In the focus of the research community are other elements as well including germanium, copper, antimony, or bismuth, and the corresponding perovskite compounds are already showing promising properties. GRAPHICAL ABSTRACT: [Image: see text

Diagnosis of caliceal diverticulum in two pediatric patients: A comparison of sonography, CT, and urography

Caliceal diverticulum is a rare disorder in which a urine-filled cavity is connected to the renal calix by a narrow isthmus. Treatment of caliceal diverticulum varies depending on the complications, which include recurrent kidney infections, hematuria, and symptomatic calculi. The use of sonography may be insufficient for accurately diagnosing this condition; contrast urography, CT, or both also may be needed. We report the cases of 2 pediatric patients whose initial sonographic diagnosis was renal cystic disease but whose final diagnosis was caliceal diverticulum on contrast-enhanced urography in 1 case and both urography and CT in the other case. The patients received no further treatment but continue to receive follow-up care to monitor for the presence of infections and calculi. Accurate diagnosis of caliceal diverticulum in both cases spared the patients and their families the psychological burden of unnecessary further investigation of renal cystic disease. These cases emphasize the importance of using contrast-enhanced imaging modalities for confirmation when sonographic findings suggest the presence of renal cystic lesions. (C) 2003 Wiley Periodicals, Inc

Investigation of Absorption Cooling Application Powered by Solar Energy in the South Coast Region of Turkey

In this study, an absorption system using ammonia-water (NH3-H2O) solution has been theoretically examined in order to meet the cooling need of a detached building having 150 m2 floor area for Antalya, Mersin and Mugla provinces in Turkey. Hourly dynamic cooling load capacities of the building were determined by using Radiant Time Series (RTS) method in the chosen cities. For the analysis, hourly average meteorological data such as atmospheric air temperature and solar radiation belonging to the years 1998-2008 are used for performance prediction of the proposed system. Thermodynamic relations for each component of absorption cooling system is explained and coefficients of performance of the system are calculated. The maximum daily total radiation data were calculated as 7173 W/m2day on July 15, 7277 W/m2 day on July 19 and 7231 W/m2day on July 19 for Mersin, Antalya and Mugla, respectively on the 23° toward to south oriented panels from horizontal surface. The generator operating temperatures are considered between 90-130°C and the best result for 110°C is found the optimum degree for maximum coefficient of performance (COP) values at the highest solar radiation occurred time during the considered days for each province. The COP values varies between 0.521 and 0.530 for the provinces. In addition, absorber and condenser capacities and thermal efficiency for the absorption cooling system were calculated. The necessary evacuated tube collector area for the different provinces were found in the range of 45 m2 to 47 m2. It is shown that although the initial investment cost is higher for the proposed absorption cooling system, it is economically feasible because of its lower annual operation costs and can successfully be operated for the considered provinces

The Missense Alteration A5T of the Thyroid Peroxidase Gene is Pathogenic and Associated with Mild Congenital Hypothyroidism

Congenital hypothyroidism (CH) occurs with a prevalence of approximately 1:4000 live births. Defects of thyroid hormone synthesis account for 15-20% of these cases. Thyroid peroxidase (TPO) gene is the most common cause for dyshormonogenesis. So far, more than 60 mutations in the TPO gene have been described, resulting in a variable decrease in TPO bioactivity. We present an 8-day-old male with mild CH who was identified to have a G to A transition in the fifth codon of the TPO gene (c.13G>A; p.Ala5Thr). The unaffected family members were heterozygous carriers of the mutation, whereas 400 healthy individuals of the same ethnic background did not have the mutation. Mutation analysis of 11 known causative CH genes and 4 of our own strong candidate genes with next-generation sequencing revealed no mutations in the patient nor in any other family members. The results of in silico functional analyses indicated partial loss-of-function (LOF) in the resulting enzyme molecule due to mutation. The patient's clinical finding s were consistent with the effect of this partial LOF of the mutation. In conclusion, we strongly believe that A5T alteration in the TPO gene is actually pathogenic and suggest that it should be classified as a mutation

The relationship between expectation, experience and perception of labour pain: an observational study.

The present study was aimed to assess the relationship between pain expectation before labour, labour pain and pain perception after the labour. Pregnant women were asked to rate their pain level on a standard continuous visual analogue scale at various time points. Pain expectancy (PE), labour pain (LP) and postpartum pain perception (PPP) scores were calculated. The final study group was composed of 230 pregnant women after exclusions. Mean age of pregnant women was 26.2 ± 5.79. The mean PE, LP, and PPP scores were 70.11 ± 18.82, 75.72 ± 19.2 and 65.84 ± 19.56, respectively. The difference among pain scores was statistically significant (p < 0.001). There was a positive correlation between PE and LP or PE and PPP scores (p = 0.27 and p = 0.21). The correlations were statistically significant (p = 0.01 or p = 0.01). In addition, there was a positive correlation between LP and PPP scores (p = 0.87) and the correlation was statistically significant (p = 0.01). This study showed that, if pregnant women had lower expectations of pain before the labour, they indeed experienced lower amount of pain during the labour