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- Chen, W. H., et al.
(författare)
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Nanophotonics-based low-temperature PECVD epitaxial crystalline silicon solar cells
- 2016
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 49:12
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Tidskriftsartikel (refereegranskat)abstract
- The enhancement of light absorption via nanopatterning in crystalline silicon solar cells is becoming extremely important with the decrease of wafer thickness for the further reduction of solar cell fabrication cost. In order to study the influence of nanopatterning on crystalline silicon thin-film solar cells, we applied two lithography techniques (laser interference lithography and nanoimprint lithography) combined with two etching techniques (dry and wet) to epitaxial crystalline silicon thin films deposited via plasma-enhanced chemical vapor deposition at 175 degrees C. The influence of nanopatterning with different etching profiles on solar cell performance is studied. We found that the etching profiles (pitch, depth and diameter) have a stronger impact on the passivation quality (open circuit voltage and fill factor) than on the optical performance (short circuit current density) of the solar cells. We also show that nanopatterns obtained via wet-etching can improve solar cell performance; and in contrast, dry-etching leads to poor passivation related to the etching profile, surface damage, and/ or contamination introduced during the etching process.
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- Daene, M, et al.
(författare)
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Outcome of Down patients with repaired versus unrepaired atrioventricular septal defect
- 2023
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Ingår i: International Journal of Cardiology Congenital Heart Disease. - : Elsevier BV. - 2666-6685. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims Patients with Down Syndrome (DS) are frequently born with an atrioventricular septal defect (AVSD). Surgical repair of the defect aims to minimize mortality and morbidity. However, a surgical intervention, specifically in DS patients, is not without risk and a subgroup of patients underwent only conservative non-surgical treatment. Outcome data of these different approaches are scarce. The aim of this retrospective study was to compare the long-term outcome of DS patients with and without surgery for AVSD. Methods DS patients registered with AVSD in the hospital's database from January 1980 till December 2020 were selected. Patient characteristics, peri-operative if appropriate, and follow-up data were obtained from the medical files. Results In total, 72 unrepaired (36 male, 50%) and 134 repaired patients (61 male, 46%) were included. After a maximum of 60 years of follow-up, the all-cause mortality was 45.8% and 17.1%, respectively. Thirty-six percent and 13%, respectively, were labeled as non-cardiovascular death. Mean survival time for unrepaired AVSD was 40.7 years (95% CI 36.1–45.2) and for repaired AVSD 38.5 years (95% CI 35.3–41.6) (Log rank p = 0.465). However, the survival rate 35 years after birth was 62.1% for unrepaired patients versus 81.7% for repaired patients. Mortality rates were the highest the first months after surgical repair. Conclusions The mean survival rate of Down patients, born with an AVSD, did not differ between repair or not. However, long-term survival rate was higher in patients who underwent surgical repair. Mortality was highest the first months after surgery.
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- Trompoukis, C., et al.
(författare)
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Photonic nanostructures for advanced light trapping in thin crystalline silicon solar cells
- 2015
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Ingår i: Physica Status Solidi (A) Applications and Materials Science. - : Wiley. - 1862-6319 .- 1862-6300. ; 212:1, s. 140-155
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Tidskriftsartikel (refereegranskat)abstract
- We report on the fabrication, integration, and simulation, both optical and optoelectrical, of two-dimensional photonic nanostructures for advanced light trapping in thin crystalline silicon (c-Si) solar cells. The photonic nanostructures are fabricated by the combination of various lithography (nanoimprint, laser interference, and hole mask colloidal) and etching (dry plasma and wet chemical) techniques. The nanopatterning possibilities thus range from periodic to random corrugations and from inverted nanopyramids to high aspect ratio profiles. Optically, the nanopatterning results in better performance than the standard pyramid texturing, showing a more robust behavior with respect to light incidence angle. Electrically, wet etching results in higher minority carrier lifetimes compared to dry etching. From the integration of the photonic nanostructures into a micron-thin c-Si solar cell certain factors limiting the efficiencies are identified. More precisely: (a) the parasitic absorption is limiting the short circuit current, (b) the conformality of thin-film coatings on the nanopatterned surface is limiting the fill factor, and (c) the material damage from dry etching is limiting the open circuit voltage. From optical simulations, the optimal pattern parameters are identified. From optoelectrical simulations, cell design considerations are discussed, suggesting to position the junction on the opposite side of the nanopattern.
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- Verheyen, Kris, et al.
(författare)
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201 Combining Biodiversity Resurveys across Regions to Advance Global Change Research
- 2017
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Ingår i: BioScience. - : Oxford University Press (OUP). - 0006-3568 .- 1525-3244. ; 67:1, s. 73-83
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Tidskriftsartikel (refereegranskat)abstract
- More and more ecologists have started to resurvey communities sampled in earlier decades to determine long-term shifts in community composition and infer the likely drivers of the ecological changes observed. However, to assess the relative importance of and interactions among multiple drivers, joint analyses of resurvey data from many regions spanning large environmental gradients are needed. In this article, we illustrate how combining resurvey data from multiple regions can increase the likelihood of driver orthogonality within the design and show that repeatedly surveying across multiple regions provides higher representativeness and comprehensiveness, allowing us to answer more completely a broader range of questions. We provide general guidelines to aid the implementation of multiregion resurvey databases. In so doing, we aim to encourage resurvey database development across other community types and biomes to advance global environmental change research.
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