Nanocrystalline n Type Silicon Front Surface Field Layers From Research to Industry Applications in Silicon Heterojunction Solar Cells

Nanocrystalline silicon and silicon oxide nc Si Ox H layers grown by plasma enhanced chemical vapor deposition PECVD have shown low parasitic absorption and excellent contact properties when implemented as n type front surface field FSF contact in rear junction silicon heterojunction SHJ solar cells [1 3]. In this contribution we present results from the successful process transfer from the lab at PVcomB at the Helmholtz Zentrum Berlin HZB , to the industrial pilot line at Meyer Burger Germany GmbH MBG . Conversion efficiencies gt; 22.5 were demonstrated on SHJ cell 4 cm2 [2, 3]. The excellent cell performance in the lab and the potential to reduce parasitic absorption in the front stack by using nc SiOx H motivated the process transfer from HZB to MBG. Initial cross processing experiments on 244 cm2 wafers showed the benefit of using nc Si H as FSF layer. We here also emphasize the role of the Si texture on a fast nc Si H nucleation. After cross processing experiments a successful transfer of the nc Si H process and fine tuning resulted in a median cell efficiency of 23.4 . This is in the same range as the MGB reference on 244 cm2 cells, noteworthy, at the same throughput. Currently work is ongoing to further improve the optical performance of the cells by adding oxygen CO

Nanocrystalline silicon oxide interlayer in monolithic perovskite silicon heterojunction tandem solar cells with total current density gt;39 mA cm2

Silicon heterojunction solar cells are implemented as bottom cells in monolithic perovskite silicon tandem solar cells. Commonly they are processed with a smooth front side to facilitate wet processing of the lead halide perovskite cell on top. The inherent drawback of this design, namely, enhanced reflection of the cell, can be significantly reduced by replacing the amorphous or nanocrystalline silicon front side n layer of the silicon cell by a nanocrystalline silicon oxide n layer. It is deposited with the same commonly used plasma enhanced chemical vapor deposition and can be tuned to feature opto electrical properties for enhanced light coupling into the Si bottom cell, namely, low parasitic absorption and an intermediate refractive index of 2.6. We demonstrate that a 80 100 nm thick layer results in 0.9 mA cm 2 current gain in the bottom cell yielding tandem cells with a top cell bottom cell total current above 39 mA cm 2 . These first nc SiO x H coupled tandem cells reach an efficiency gt;23.

What is blue growth? The semantics of “Sustainable Development” of marine environments

This Special Issue is intended to help readers gain a better understanding of the various definitions of blue growth, as well as to give a heightened awareness of the constraints of, and possibilities within, the important concept. Increased communication among those working together on these topics is of utmost importance, especially considering the diversity of the backgrounds of those who have a role to play in blue growth and sustainable development. Scientists, policy makers, business people, and the larger society need to become more precise and transparent in their language and meanings in order to effectively work together, and hopefully one day succeed in our joint goal to secure blue growth

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Ultra thin nanocrystalline n type silicon oxide front contact layers for rear emitter silicon heterojunction solar cells

Hydrogenated nanocrystalline silicon oxide nc SiOx H films have demonstrated a unique combination of low parasitic absorption and high conductivity. Here, we report on the use of n type nc SiOx H as front surface field FSF in rear emitter silicon heterojunction SHJ solar cells exhibiting excellent electrical cell parameters at a thickness down to only 5 amp; 8239;nm. Using a seed layer, we are able to maintain excellent electrical performance high fill factor FF and open circuit voltage VOC , while enhancing layer transparency for maximizing short circuit current JSC . These results, together with the short deposition time lt; 100 amp; 8239;s , make the n nc SiOx H FSF attractive for reducing production costs in industrial applications. The best device, with the optimized n nc SiOx H FSF layer, shows VOC of 731 amp; 8239;mV, FF of 80.6 , JSC of 38.3 amp; 8239;mA cm2 and a power conversion efficiency of 22.

Versatility of Nanocrystalline Silicon Films from Thin Film to Perovskite c Si Tandem Solar Cell Applications

Doped hydrogenated nanocrystalline nc Si H and silicon oxide nc SiO x H materials grown by plasma enhanced chemical vapor deposition have favourable optoelectronic properties originated from their two phase structure. This unique combination of qualities, initially, led to the development of thin film Si solar cells allowing the fabrication of multijunction devices by tailoring the material bandgap. Furthermore, nanocrystalline silicon films can offer a better carrier transport and field effect passivation than amorphous Si layers could do, and this can improve the carrier selectivity in silicon heterojunction SHJ solar cells. The reduced parasitic absorption, due to the lower absorption coefficient of nc SiO x H films in the relevant spectral range, leads to potential gain in short circuit current. In this work, we report on development and applications of hydrogenated nanocrystalline silicon oxide nc SiO x H from material to device level. We address the potential benefits and the challenges for a successful integration in SHJ solar cells. Finally, we prove that nc SiO x H demonstrated clear advantages for maximizing the infrared response of c Si bottom cells in combination with perovskite top cell

ITO Free Silicon Heterojunction Solar Cells With ZnO Al SiO2Front Electrodes Reaching a Conversion Efficiency of 23

Silicon heterojunction SHJ solar cells have been increasingly attracting attention to the photovoltaic community in the last years due to their high efficiency potential and the lean production process. We report on the development of a stable baseline process for SHJ cells with focus on the optical improvement of the solar cells front side. An amorphous silicon oxide layer a SiO 2 was used as an antireflective coating AR on the front side the finished SHJ devices. Both optical simulations and experimental results demonstrate a short circuit current density J sc improvement of 0.4 mA cm 2 when applying the a SiO 2 AR, yielding maximum conversion efficiencies of 23.0 . Full size cells with 244 cm 2 total area have been produced using three front contact stacks indium tin oxide ITO as reference, ZnO Al, and ZnO Al SiO 2 showing the J sc improvement with the double AR configuration. Damp heat tests on those samples demonstrate an enhanced stability of cells with ZnO Al front TCO when capped with SiO

Evidence for the role of interferon-alfa production by dendritic cells in the Th1 response in celiac disease

Background & Aims: Dendritic cells (DCs) play a crucial role in immune responses by controlling the extent and type of T-cell response to antigen. Celiac disease is a condition in which T-cell immunity to gluten plays an important pathogenic role, yet information on DCs is scant. We examined mucosal DCs in celiac disease in terms of phenotype, activation/maturation state, cytokine production, and function. Methods: Mucosal DCs from 48 celiacs and 30 controls were investigated by flow cytometry. In situ distribution of DCs was analyzed by confocal microscopy. Interferon (IFN)-alfa, interleukin (IL)-4, IL-5, IL-12p35, IL-12p40, IL-18, IL-23p19, IL-27, and transforming growth factor-beta transcripts were measured by real-time reverse-transcription polymerase chain reaction in sorted DCs. DC expression of IL-6, IL12p40, and IL-10 was assessed by intracellular cytokine staining. The effect of IFN-alfa and IL-18 blockade on the gluten-induced IFN-gamma response in celiac biopsy specimens grown ex vivo also was investigated. Results: Mucosal DCs were increased in untreated, but not treated, celiacs. The majority of them were plasmacytoid with higher levels of maturation (CD83) and activation (CD80/CD86) markers. Higher transcripts of Th1 relevant cytokines, such as IFN-alfa, IL-18, and IL-23p19, were produced by celiac DCs, but because IL-12p40 was undetectable, a role for IL-23 is unlikely. Intracellular cytokine staining of celiac DCs showed higher IL-6, but lower IL-10 expression, and confirmed the lack of IL-12p40. Blocking IFN-alfa inhibited IFN-gamma transcripts in ex vivo organ culture of celiac biopsy specimens challenged with gluten. Conclusions: These data suggest that IFN-alfa-producing DCs contribute to the Th1 response in celiac disease