Experimental evidence on removing copper and light-induced degradation from silicon by negative charge

In addition to boron and oxygen, copper is also known to cause light-induced degradation (LID) in silicon. We have demonstrated previously that LID can be prevented by depositing negative corona charge onto the wafer surfaces. Positively charged interstitial copper ions are proposed to diffuse to the negatively charged surface and consequently empty the bulk of copper. In this study, copper out-diffusion was confirmed by chemical analysis of the near surface region of negatively/positively charged silicon wafer. Furthermore, LID was permanently removed by etching the copper-rich surface layer after negative charge deposition. These results demonstrate that (i) copper can be effectively removed from the bulk by negative charge, (ii) under illumination copper forms a recombination active defect in the bulk of the wafer causing severe light induced degradation.Peer reviewe

Simulation based Development of Industrial PERC Cell Production beyond 20.5% Efficiency

AbstractIn this work we present our approach to realize an industrial process that allows cell efficiencies up to and above 21%. Based on a loss analysis we systematically investigate the feasible options to improve the efficiency with device simulations and production experiments. Subsequently we perform sensitivity analyses particularly for various silicon wafer materials to ensure stable process capability. Our best prototype process with optimized front and rear side passivation and enhanced laser contact patterning has demonstrated a maximum efficiency of 20.9% with a very high VOC of 670mV on high-lifetime mono material. We were able to assemble 60-cell based modules with more than 305Wp

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Signals of onomastic capital : From transhistorical roots to the contemporary globalized trend of sponsored names

Proposing and elaborating upon the concept of onomastic capital as a multidisciplinary lens for socio-onomastic research, this article considers some of the historical underpinnings that contribute to onomastic capital, before focusing specifically on the recent dramatic growth in the phenomenon of selling naming rights to (semi-)public spaces. This marketization of names has been especially visible in sports and entertainment venues. To examine emerging naming patterns and practices resulting from such name sponsorship activity, the article explores a database of onomastic material from a variety of European contexts: England and Wales, Finland, Germany, Italy, Norway and Scotland.Peer reviewe

Signals of onomastic capital : From transhistorical roots to the contemporary globalized trend of sponsored names

Proposing and elaborating upon the concept of onomastic capital as a multidisciplinary lens for socio-onomastic research, this article considers some of the historical underpinnings that contribute to onomastic capital, before focusing specifically on the recent dramatic growth in the phenomenon of selling naming rights to (semi-)public spaces. This marketization of names has been especially visible in sports and entertainment venues. To examine emerging naming patterns and practices resulting from such name sponsorship activity, the article explores a database of onomastic material from a variety of European contexts: England and Wales, Finland, Germany, Italy, Norway and Scotland.Peer reviewe

(oral talk) Vertically integrated modeling of light-induced defects: Process modeling, degradation kinetics and device impact

| openaire: EC/FP7/307315/EU//SOLARXPeer reviewe

Vertically integrated modeling of light-induced defects

| openaire: EC/FP7/307315/EU//SOLARXAs photovoltaic (PV) device architectures advance, they turn more sensitive to bulk minority charge carrier lifetime. The conflicting needs to develop ever advancing cell architectures on ever cheapening silicon substrates ensure that various impurity-related light-induced degradation (LID) mechanisms will remain an active research area in the silicon PV community. Here, we propose vertically integrated defect modeling as a framework to accelerate the identification and mitigation of different light induced defects. More specifically, we propose using modeled LID-kinetics to identify the dominant LID mechanism or mechanisms within complete PV devices. Coupling the LID-kinetics model into a process model allows development of process guidelines to mitigate the identified LID-mechanism within the same vertically integrated simulation tool. We use copper as an example of a well-characterized light-induced defect: we model the evolution of copper during solar cell processing and light soaking, and then map the deleterious lifetime effect of Cu-LID onto device performance. We validate our model using intentionally Cu-contaminated material processed on an industrial PERC-line and find that our model reproduces the LID-behavior of the manufactured solar cells. We further show via simulations that Cu-LID can be mitigated by reducing the contact co-firing peak temperature, or the cooling rate after the firing process.Peer reviewe